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| author | Marti Bolivar <mbolivar@mit.edu> | 2010-12-21 10:27:37 -0500 |
|---|---|---|
| committer | Marti Bolivar <mbolivar@mit.edu> | 2010-12-21 10:27:37 -0500 |
| commit | c45bccad44187da27505cf5808424e709e3f54a1 (patch) | |
| tree | 18a459a50f8d0551ba046e30462c93999d982725 /docs/source | |
| parent | 84fd2532a7f23d20354ff590790b3f892cb7e7d7 (diff) | |
| parent | d5ad2a27f4e69e6cc9324331945937c983c30366 (diff) | |
| download | librambutan-c45bccad44187da27505cf5808424e709e3f54a1.tar.gz librambutan-c45bccad44187da27505cf5808424e709e3f54a1.zip | |
Merge branch 'master' into debug-serialusb.
Chose debug-serialusb version in cases of conflict.
Conflicts:
libmaple/usb/usb_callbacks.c
Diffstat (limited to 'docs/source')
239 files changed, 9174 insertions, 7313 deletions
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Function Reference ------------------ -TODO function reference (figure out Doxygen first) +.. doxygenfunction:: analogRead + +.. doxygenfunction:: pinMode + +.. doxygenenum:: WiringPinMode .. _adc-recommended-reading: diff --git a/docs/source/arduino/abs.rst b/docs/source/arduino/abs.rst deleted file mode 100644 index 5d699ae..0000000 --- a/docs/source/arduino/abs.rst +++ /dev/null @@ -1,33 +0,0 @@ -.. _arduino-abs: - -abs(x) -====== - -Description ------------ - -(Macro) computes the absolute value of a number. - -Parameters ----------- - -**x**: the number - -Returns -------- - -**x**: if **x** is greater than or equal to 0. - -**-x**: if **x** is less than 0. - -Warning -------- - -Because of the way ``abs()`` is implemented, avoid using other -functions or causing side effects inside the brackets, as it may lead -to incorrect results :: - - abs(a++); // avoid this - yields incorrect results - - a++; // use this instead - - abs(a); // keep other math outside the function diff --git a/docs/source/arduino/analogread.rst b/docs/source/arduino/analogread.rst deleted file mode 100644 index d0fa5a1..0000000 --- a/docs/source/arduino/analogread.rst +++ /dev/null @@ -1,134 +0,0 @@ -.. highlight:: cpp - -.. _arduino-analogread: - -analogRead() -============ - - -Signature ---------- - -``int analogRead(int pin);`` - - -Description ------------ - -Reads the value from the specified analog pin. The Maple board -contains a 16-channel, 12-bit analog to digital converter. This means -that it will map input voltages between 0 and 3.3 volts into integer -values between 0 and 4095. This yields a resolution between readings -of 3.3V / 4096 units, or 0.8 millivolts. However, a number of factors -interfere with getting full accuracy and precision. For more -information, see :ref:`adc`. - -Before calling analogRead() on a pin, that pin must first be -configured for analog input, using :ref:`arduino-pinMode`. - -The input range and resolution can be changed using -:ref:`arduino-analogReference`. - -It takes about 0.8 microseconds (.0000008 seconds) to read an analog -input, so the maximum sample rate using this function is approximately -1.3 million samples per second [#fsamp]_. - - -Parameters ----------- - -**pin** - - The number of the analog input pin to read from. Header pins on the - Maple with ADC functionality (marked as "AIN" on the silkscreen) - are: - - 0, 1, 2, 3, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 27, 28 - - Note that pins 3, 27, and 28 are not marked AIN on the silkscreen - for Maple revisions through Rev 5, however, they **do work** as - analog input pins. - -Returns -------- - -Converted input voltage as an ``int``, with value 0 to 4095, inclusive. - - -Note ----- - -If the analog input pin is not connected to anything, the value -returned by analogRead() will fluctuate based on a number of factors -(e.g. the values of the other analog inputs, how close your hand is to -the board, etc.). - - -Example -------- - - :: - - - int analogPin = 3; // potentiometer wiper (middle terminal) connected to analog pin 3 - // outside leads to ground and +3.3V - int val = 0; // variable to store the value read - - void setup() { - pinMode(analogPin, INPUT_ANALOG); - SerialUSB.begin(); - } - - void loop() { - val = analogRead(analogPin); // read the input pin - SerialUSB.println(val); // debug value - } - - -Arduino Compatibility Note --------------------------- - -The Arduino board contains a 6 channel (8 channels on the Mini and -Nano, 16 on the Mega), 10-bit analog to digital converter. This means -that it will map input voltages between 0 and 5 volts into integer -values between 0 and 1023. This yields a resolution between readings -of: 5 volts / 1024 units or, .0049 volts (4.9 mV) per unit. On the -Arduino, the input range and resolution can be changed using their -implementation of `analogReference() -<http://arduino.cc/en/Reference/AnalogReference>`_\ . - -On the Arduino, it takes about 100 microseconds (0.0001 s) to read an -analog input, so the maximum reading rate is about 10,000 times a -second. - - -See also --------- - -- :ref:`ADC note <adc>` -- :ref:`analogReference <arduino-analogreference>` -- `(Arduino) Tutorial: Analog Input Pins <http://arduino.cc/en/Tutorial/AnalogInputPins>`_ - - -.. rubric:: Footnotes - -.. [#fsamp] This is based on the current configuration of a 55.5 cycle - sample time, at 72 MHz. However, the minimum sample time *possible* - is 1.5 cycles, leading to a theoretical maximum of approximately 48 - million samples per second (of course, doing anything with the - readings also consumes cycles, so this maximum can't be reached in - practice). - - See the `STM32 Reference Manual <full-manual>`_, §§11.12.4--5 - (pp. 225--226), for more information on the low-level bit twiddling - currently necessary to change the sample time. For examples of how - the ADCs are configured in libmaple, see `adc.h - <http://github.com/leaflabs/libmaple/blob/master/libmaple/adc.h>`_ - and `adc.c - <http://github.com/leaflabs/libmaple/blob/master/libmaple/adc.c>`_\ - . Be aware that changing the sample time has important - consequences related to the impedance of the device connected to - the input pin. If you want to make changes, as a minimum, you - should first read ST's application notes on `ADC modes - <stm32-adc-modes>`_ and `ADC oversampling - <stm32-adc-oversampling>`_. diff --git a/docs/source/arduino/analogreference.rst b/docs/source/arduino/analogreference.rst deleted file mode 100644 index 9a25169..0000000 --- a/docs/source/arduino/analogreference.rst +++ /dev/null @@ -1,66 +0,0 @@ -.. _arduino-analogreference: - -analogReference(type) -===================== - -Description ------------ - -Configures the reference voltage used for analog input (i.e. the -value used as the top of the input range). The options are: - - - - -- DEFAULT: the default analog reference of 5 volts (on 5V Arduino - boards) or 3.3 volts (on 3.3V Arduino boards) -- INTERNAL: an built-in reference, equal to 1.1 volts on the - ATmega168 or ATmega328 and 2.56 volts on the ATmega8. -- EXTERNAL: the voltage applied to the AREF pin is used as the - reference. - - - -Parameters ----------- - -type: which type of reference to use (DEFAULT, INTERNAL, or -EXTERNAL). - - - -Returns -------- - -None. - - - -Warning -------- - -**If you're using an external reference voltage (applied to the AREF pin), you must set the analog reference to EXTERNAL before calling analogRead().** -Otherwise, you will short together the active reference voltage -(internally generated) and the AREF pin, possibly damaging the -microcontroller on your Arduino board. - - - -Alternatively, you can connect the external reference voltage to -the AREF pin through a 5K resistor, allowing you to switch between -external and internal reference voltages. Note that the resistor -will alter the voltage that gets used as the reference because -there is an internal 32K resistor on the AREF pin. The two act as a -voltage divider, so, for example, 2.5V applied through the resistor -will yield 2.5 \* 32 / (32 + 5) = ~2.2V at the AREF pin. - - - -See also --------- - - -- `Description of the analog input pins <http://arduino.cc/en/Tutorial/AnalogInputPins>`_ -- `analogRead <http://arduino.cc/en/Reference/AnalogRead>`_\ () - - diff --git a/docs/source/arduino/analogwrite.rst b/docs/source/arduino/analogwrite.rst deleted file mode 100644 index 64ecd5b..0000000 --- a/docs/source/arduino/analogwrite.rst +++ /dev/null @@ -1,116 +0,0 @@ -.. _arduino-analogwrite: - -analogWrite() -============= - -TODO - -In libmaple, analogWrite is just a convenience alias for -:ref:`pwmWrite`. This is because PWM is not true analog output (i.e., -is not the output of a DAC), so the name was badly-chosen; however, -for the sake of compatibility, the alias was provided. - -.. doxygenfunction:: pwmWrite - -Description ------------ - -Writes an analog value -(`PWM wave <http://arduino.cc/en/Tutorial/PWM>`_) to a pin. Can be -used to light a LED at varying brightnesses or drive a motor at -various speeds. After a call to **analogWrite()**, the pin will -generate a steady square wave of the specified duty cycle until the -next call to **analogWrite()** (or a call to **digitalRead()** or -**digitalWrite()** on the same pin). The frequency of the PWM -signal is approximately 490 Hz. - - - -On most Arduino boards (those with the ATmega168 or ATmega328), -this function works on pins 3, 5, 6, 9, 10, and 11. On the Arduino -Mega, it works on pins 2 through 13. Older Arduino boards with an -ATmega8 only support analogWrite() on pins 9, 10, and 11. You do -not need to call pinMode() to set the pin as an output before -calling analogWrite(). - - - -The *analogWrite* function has nothing whatsoever to do with the -analog pins or the *analogRead* function. - - - -Syntax ------- - -analogWrite(pin, value) - - - -Parameters ----------- - -pin: the pin to write to. - - - -value: the duty cycle: between 0 (always off) and 255 (always on). - - - -Returns -------- - -nothing - - - -Notes and Known Issues ----------------------- - -The PWM outputs generated on pins 5 and 6 will have -higher-than-expected duty cycles. This is because of interactions -with the millis() and delay() functions, which share the same -internal timer used to generate those PWM outputs. This will be -noticed mostly on low duty-cycle settings (e.g 0 - 10) and may -result in a value of 0 not fully turning off the output on pins 5 -and 6. - - - -Example -------- - -Sets the output to the LED proportional to the value read from the -potentiometer. - - - -:: - - - int ledPin = 9; // LED connected to digital pin 9 - int analogPin = 3; // potentiometer connected to analog pin 3 - int val = 0; // variable to store the read value - - void setup() - { - pinMode(ledPin, OUTPUT); // sets the pin as output - } - - void loop() - { - val = analogRead(analogPin); // read the input pin - analogWrite(ledPin, val / 4); // analogRead values go from 0 to 1023, analogWrite values from 0 to 255 - } - - - -See also --------- - - -- `analogRead <http://arduino.cc/en/Reference/AnalogRead>`_\ () -- `Tutorial: PWM <http://arduino.cc/en/Tutorial/PWM>`_ - - diff --git a/docs/source/arduino/arithmetic.rst b/docs/source/arduino/arithmetic.rst deleted file mode 100644 index cbe3059..0000000 --- a/docs/source/arduino/arithmetic.rst +++ /dev/null @@ -1,104 +0,0 @@ -.. highlight:: cpp - -.. _arduino-arithmetic: - -Addition, Subtraction, Multiplication, & Division -================================================= - -Description ------------ - -These operators return the sum, difference, product, or quotient -(respectively) of the two operands. The operation is conducted using -the data type of the operands, so, for example, ``9 / 4`` gives ``2`` -since 9 and 4 are ints. - -This also means that the operation can overflow if the result is -larger than that which can be stored in the data type (e.g. adding 1 -to an :ref:`arduino-int` with the value 2147483647 gives --2147483648). If the operands are of different types, the "larger" -type is used for the calculation. - -(The specifics of these rules are beyond the scope of this -documentation; for more information, see `The C++ Programming Language -<http://www2.research.att.com/~bs/3rd.html>`_\ , by Bjarne -Stroustroup, Appendix C, especially §§C.4-C.6, or `this WikiBooks -entry on C++ type conversion -<http://en.wikibooks.org/wiki/C%2B%2B_Programming/Programming_Languages/C%2B%2B/Code/Statements/Variables/Type_Casting#Automatic_type_conversion>`_\ -. For more information on how computers represent integers, see the -Wikipedia page on `two's complement -<http://en.wikipedia.org/wiki/Two's_complement>`_\ ). - -If one of the numbers (operands) are of the type **float** or of type -**double**, floating point math will be used for the -calculation. - -Examples --------- - - :: - - y = y + 3; - x = x - 7; - i = j * 6; - r = r / 5; - - -Syntax ------- - - :: - - result = value1 + value2; - result = value1 - value2; - result = value1 * value2; - result = value1 / value2; - - -Parameters: ------------ - -**value1**: any numeric variable or constant - -**value2**: any numeric variable or constant - - -Arduino Compatibility Note --------------------------- - -Since the STM32 processor on the Maple is a 32-bit machine, the int -type overflows at a much higher value on Maple than on Arduino. In -particular, on Maple, ints do not overflow (become negative) until -they reach 2,147,483,648; on the Arduino, they overflow at 32,767. -Because of this, programs running on Maple are much less likely to run -into overflow issues. - - -Programming Tips: ------------------ - -- Know that :ref:`integer constants <arduino-integerconstants>` - default to :ref:`int <arduino-Int>`, so some constant calculations - may overflow (e.g., 200000 * 5000000 will yield a negative result). - -- Choose variable sizes that are large enough to hold the largest - results from your calculations. - -- Know at what point your variable will "roll over" and also what - happens in the other direction e.g. (0 - 1) for unsigned arithmetic, - or (0 - -2,147,483,648) for signed arithmetic. - -- For math that requires fractions, float variables may be used, but - be aware of their drawbacks: large size and slow computation speeds - (the STM32 has no floating point hardware, so all floating point - calculations have to be done in software). - -- Use the cast operator e.g. (int)myFloat to convert one variable type - to another on the fly. - - -See Also --------- - -- `libmaple_types.h <http://github.com/leaflabs/libmaple/blob/master/libmaple/libmaple_types.h>`_ - diff --git a/docs/source/arduino/bit.rst b/docs/source/arduino/bit.rst deleted file mode 100644 index f8241a5..0000000 --- a/docs/source/arduino/bit.rst +++ /dev/null @@ -1,42 +0,0 @@ -.. _arduino-bit: - -bit() -===== - -Description ------------ - -Computes the value of the specified bit (bit 0 is 1, bit 1 is 2, -bit 2 is 4, etc.). - - - -Syntax ------- - -bit(n) - - - -Parameters ----------- - -n: the bit whose value to compute - - - -Returns -------- - -the value of the bit - - - -See also --------- - - -- `bitRead <http://arduino.cc/en/Reference/BitRead>`_\ () -- `bitWrite <http://arduino.cc/en/Reference/BitWrite>`_\ () -- `bitSet <http://arduino.cc/en/Reference/BitSet>`_\ () -- `bitClear <http://arduino.cc/en/Reference/BitClear>`_\ () diff --git a/docs/source/arduino/bitclear.rst b/docs/source/arduino/bitclear.rst deleted file mode 100644 index e86dbc5..0000000 --- a/docs/source/arduino/bitclear.rst +++ /dev/null @@ -1,48 +0,0 @@ -.. _arduino-bitclear: - -bitClear() -========== - -Description ------------ - -Clears (writes a 0 to) a bit of a numeric variable. - - - -Syntax ------- - -bitClear(x, n) - - - -Parameters ----------- - -x: the numeric variable whose bit to clear - - - -n: which bit to clear, starting at 0 for the least-significant -(rightmost) bit - - - -Returns -------- - -none - - - -See also --------- - - -- `bit <http://arduino.cc/en/Reference/Bit>`_\ () -- `bitRead <http://arduino.cc/en/Reference/BitRead>`_\ () -- `bitWrite <http://arduino.cc/en/Reference/BitWrite>`_\ () -- `bitSet <http://arduino.cc/en/Reference/BitSet>`_\ () - - diff --git a/docs/source/arduino/bitread.rst b/docs/source/arduino/bitread.rst deleted file mode 100644 index 3d0b1a4..0000000 --- a/docs/source/arduino/bitread.rst +++ /dev/null @@ -1,48 +0,0 @@ -.. _arduino-bitread: - -bitRead() -========= - -Description ------------ - -Reads a bit of a number. - - - -Syntax ------- - -bitRead(x, n) - - - -Parameters ----------- - -x: the number from which to read - - - -n: which bit to read, starting at 0 for the least-significant -(rightmost) bit - - - -Returns -------- - -the value of the bit (0 or 1). - - - -See also --------- - - -- `bit <http://arduino.cc/en/Reference/Bit>`_\ () -- `bitWrite <http://arduino.cc/en/Reference/BitWrite>`_\ () -- `bitSet <http://arduino.cc/en/Reference/BitSet>`_\ () -- `bitClear <http://arduino.cc/en/Reference/BitClear>`_\ () - - diff --git a/docs/source/arduino/bitset.rst b/docs/source/arduino/bitset.rst deleted file mode 100644 index 882ec92..0000000 --- a/docs/source/arduino/bitset.rst +++ /dev/null @@ -1,47 +0,0 @@ -.. _arduino-bitset: - -bitSet() -======== - -Description ------------ - -Sets (writes a 1 to) a bit of a numeric variable. - - - -Syntax ------- - -bitSet(x, n) - - - -Parameters ----------- - -x: the numeric variable whose bit to set - - - -n: which bit to set, starting at 0 for the least-significant -(rightmost) bit - - - -Returns -------- - -none - - - -See also --------- - - -- `bit <http://arduino.cc/en/Reference/Bit>`_\ () -- `bitRead <http://arduino.cc/en/Reference/BitRead>`_\ () -- `bitWrite <http://arduino.cc/en/Reference/BitWrite>`_\ () -- `bitClear <http://arduino.cc/en/Reference/BitClear>`_\ () - diff --git a/docs/source/arduino/bitshift.rst b/docs/source/arduino/bitshift.rst deleted file mode 100644 index f59b489..0000000 --- a/docs/source/arduino/bitshift.rst +++ /dev/null @@ -1,127 +0,0 @@ -.. _arduino-bitshift: - -bitshift left (<<), bitshift right (>>) -======================================= - -Description ------------ - -From *The Bitmath Tutorial* in The Playground - - - -There are two bit shift operators in C++: the left shift operator -<< and the right shift operator >>. These operators cause the bits -in the left operand to be shifted left or right by the number of -positions specified by the right operand. -More on bitwise math may be found -`here. <http://www.arduino.cc/playground/Code/BitMath>`_ - - - -Syntax ------- - -variable << number\_of\_bits - - - -variable >> number\_of\_bits - - - -Parameters ----------- - -variable - (byte, int, long) number\_of\_bits integer <= 32 - - - -Example: --------- - -:: - - int a = 5; // binary: 0000000000000101 - int b = a << 3; // binary: 0000000000101000, or 40 in decimal - int c = b >> 3; // binary: 0000000000000101, or back to 5 like we started with - - - -When you shift a value x by y bits (x << y), the leftmost y bits in -x are lost, literally shifted out of existence: - - - -:: - - int a = 5; // binary: 0000000000000101 - int b = a << 14; // binary: 0100000000000000 - the first 1 in 101 was discarded - - - -If you are certain that none of the ones in a value are being -shifted into oblivion, a simple way to think of the left-shift -operator is that it multiplies the left operand by 2 raised to the -right operand power. For example, to generate powers of 2, the -following expressions can be employed: - - - -:: - - 1 << 0 == 1 - 1 << 1 == 2 - 1 << 2 == 4 - 1 << 3 == 8 - ... - 1 << 8 == 256 - 1 << 9 == 512 - 1 << 10 == 1024 - ... - - - -When you shift x right by y bits (x >> y), and the highest bit in x -is a 1, the behavior depends on the exact data type of x. If x is -of type int, the highest bit is the sign bit, determining whether x -is negative or not, as we have discussed above. In that case, the -sign bit is copied into lower bits, for esoteric historical -reasons: - - - -:: - - int x = -16; // binary: 1111111111110000 - int y = x >> 3; // binary: 1111111111111110 - - - -This behavior, called sign extension, is often not the behavior you -want. Instead, you may wish zeros to be shifted in from the left. -It turns out that the right shift rules are different for unsigned -int expressions, so you can use a typecast to suppress ones being -copied from the left: - - - -:: - - int x = -16; // binary: 1111111111110000 - int y = (unsigned int)x >> 3; // binary: 0001111111111110 - - - -If you are careful to avoid sign extension, you can use the -right-shift operator >> as a way to divide by powers of 2. For -example: - - - -:: - - int x = 1000; - int y = x >> 3; // integer division of 1000 by 8, causing y = 125. - - diff --git a/docs/source/arduino/bitwiseand.rst b/docs/source/arduino/bitwiseand.rst deleted file mode 100644 index 8d4eb3f..0000000 --- a/docs/source/arduino/bitwiseand.rst +++ /dev/null @@ -1,230 +0,0 @@ -.. _arduino-bitwiseand: - -Bitwise AND (&), Bitwise OR (\|), Bitwise XOR (^) -================================================= - -Bitwise AND (&) ---------------- - -The bitwise operators perform their calculations at the bit level -of variables. They help solve a wide range of common programming -problems. Much of the material below is from an excellent tutorial -on bitwise math wihch may be found -`here. <http://www.arduino.cc/playground/Code/BitMath>`_ - - - -Description and Syntax ----------------------- - -Below are descriptions and syntax for all of the operators. Further -details may be found in the referenced tutorial. - - - -Bitwise AND (&) ---------------- - -The bitwise AND operator in C++ is a single ampersand, &, used -between two other integer expressions. Bitwise AND operates on each -bit position of the surrounding expressions independently, -according to this rule: if both input bits are 1, the resulting -output is 1, otherwise the output is 0. Another way of expressing -this is: - - - -:: - - 0 0 1 1 operand1 - 0 1 0 1 operand2 - ---------- - 0 0 0 1 (operand1 & operand2) - returned result - - - -In Arduino, the type int is a 16-bit value, so using & between two -int expressions causes 16 simultaneous AND operations to occur. In -a code fragment like: - - - -:: - - int a = 92; // in binary: 0000000001011100 - int b = 101; // in binary: 0000000001100101 - int c = a & b; // result: 0000000001000100, or 68 in decimal. - - - -Each of the 16 bits in a and b are processed by using the bitwise -AND, and all 16 resulting bits are stored in c, resulting in the -value 01000100 in binary, which is 68 in decimal. - - - -One of the most common uses of bitwise AND is to select a -particular bit (or bits) from an integer value, often called -masking. See below for an example - - - -Bitwise OR (\|) ---------------- - -The bitwise OR operator in C++ is the vertical bar symbol, \|. Like -the & operator, \| operates independently each bit in its two -surrounding integer expressions, but what it does is different (of -course). The bitwise OR of two bits is 1 if either or both of the -input bits is 1, otherwise it is 0. In other words: - - - -:: - - 0 0 1 1 operand1 - 0 1 0 1 operand2 - ---------- - 0 1 1 1 (operand1 | operand2) - returned result - - - -Here is an example of the bitwise OR used in a snippet of C++ -code: - - - -:: - - int a = 92; // in binary: 0000000001011100 - int b = 101; // in binary: 0000000001100101 - int c = a | b; // result: 0000000001111101, or 125 in decimal. - - - -Example Program ---------------- - -A common job for the bitwise AND and OR operators is what -programmers call Read-Modify-Write on a port. On microcontrollers, -a port is an 8 bit number that represents something about the -condition of the pins. Writing to a port controls all of the pins -at once. - - - -PORTD is a built-in constant that refers to the output states of -digital pins 0,1,2,3,4,5,6,7. If there is 1 in an bit position, -then that pin is HIGH. (The pins already need to be set to outputs -with the pinMode() command.) So if we write ``PORTD = B00110001;`` -we have made pins 2,3 & 7 HIGH. One slight hitch here is that we -*may* also have changeed the state of Pins 0 & 1, which are used by -the Arduino for serial communications so we may have interfered -with serial communication. - - - -:: - - Our algorithm for the program is: - - -- Get PORTD and clear out only the bits corresponding to the pins - we wish to control (with bitwise AND). -- Combine the modified PORTD value with the new value for the pins - under control (with biwise OR). - - - -:: - - int i; // counter variable - int j; - - void setup(){ - DDRD = DDRD | B11111100; // set direction bits for pins 2 to 7, leave 0 and 1 untouched (xx | 00 == xx) - // same as pinMode(pin, OUTPUT) for pins 2 to 7 - Serial.begin(9600); - } - - void loop(){ - for (i=0; i<64; i++){ - - PORTD = PORTD & B00000011; // clear out bits 2 - 7, leave pins 0 and 1 untouched (xx & 11 == xx) - j = (i << 2); // shift variable up to pins 2 - 7 - to avoid pins 0 and 1 - PORTD = PORTD | j; // combine the port information with the new information for LED pins - Serial.println(PORTD, BIN); // debug to show masking - delay(100); - } - } - - - -Bitwise XOR (^) ---------------- - -There is a somewhat unusual operator in C++ called bitwise -EXCLUSIVE OR, also known as bitwise XOR. (In English this is -usually pronounced "eks-or".) The bitwise XOR operator is written -using the caret symbol ^. This operator is very similar to the -bitwise OR operator \|, only it evaluates to 0 for a given bit -position when both of the input bits for that position are 1: - - - -:: - - 0 0 1 1 operand1 - 0 1 0 1 operand2 - ---------- - 0 1 1 0 (operand1 ^ operand2) - returned result - - - -Another way to look at bitwise XOR is that each bit in the result -is a 1 if the input bits are different, or 0 if they are the same. - - - -Here is a simple code example: - - - -:: - - int x = 12; // binary: 1100 - int y = 10; // binary: 1010 - int z = x ^ y; // binary: 0110, or decimal 6 - - - -The ^ operator is often used to toggle (i.e. change from 0 to 1, or -1 to 0) some of the bits in an integer expression. In a bitwise OR -operation if there is a 1 in the mask bit, that bit is inverted; if -there is a 0, the bit is not inverted and stays the same. Below is -a program to blink digital pin 5. - - - -:: - - // Blink_Pin_5 - // demo for Exclusive OR - void setup(){ - DDRD = DDRD | B00100000; // set digital pin five as OUTPUT - Serial.begin(9600); - } - - void loop(){ - PORTD = PORTD ^ B00100000; // invert bit 5 (digital pin 5), leave others untouched - delay(100); - } - - - -See Also - - -- `&& <http://arduino.cc/en/Reference/Boolean>`_ (Boolean AND) -- `\|\| <http://arduino.cc/en/Reference/Boolean>`_ (Boolean OR) - diff --git a/docs/source/arduino/bitwisecompound.rst b/docs/source/arduino/bitwisecompound.rst deleted file mode 100644 index c3c808f..0000000 --- a/docs/source/arduino/bitwisecompound.rst +++ /dev/null @@ -1,227 +0,0 @@ -.. _arduino-bitwisecompound: - -compound bitwise AND (&=), compound bitwise OR (\|=) -==================================================== - -The compound bitwise operators perform their calculations at the -bit level of variables. They are often used to clear and set -specific bits of a variable. - - - -See the -`bitwise AND (&) <http://arduino.cc/en/Reference/BitwiseAnd>`_ and -`bitwise OR (\|) <http://arduino.cc/en/Reference/BitwiseAnd>`_ -operators for the details of their operation, and also the -`Bitmath Tutorial <http://www.arduino.cc/playground/Code/BitMath>`_ -for more information on bitwise operators. - - - -compound bitwise AND (&=) -========================= - -Description ------------ - -The compound bitwise AND operator (&=) is often used with a -variable and a constant to force particular bits in a variable to -the LOW state (to 0). This is often referred to in programming -guides as "clearing" or "resetting" bits. - - - -Syntax: -------- - -:: - - x &= y; // equivalent to x = x & y; - - - -Parameters ----------- - -x: a char, int or long variable -y: an integer constant or char, int, or long - - - -Example: --------- - -First, a review of the Bitwise AND (&) operator - -:: - - 0 0 1 1 operand1 - 0 1 0 1 operand2 - ---------- - 0 0 0 1 (operand1 & operand2) - returned result - - - -Bits that are "bitwise ANDed" with 0 are cleared to 0 so, if myByte -is a byte variable, -``myByte & B00000000 = 0;`` - - - -Bits that are "bitwise ANDed" with 1 are unchanged so, -``myByte & B11111111 = myByte;`` - - - -Note: because we are dealing with bits in a bitwise operator - it -is convenient to use the binary formatter with -`constants. <http://arduino.cc/en/Reference/IntegerConstants>`_ The -numbers are still the same value in other representations, they are -just not as easy to understand. Also, B00000000 is shown for -clarity, but zero in any number format is zero (hmmm something -philosophical there?) - - - -Consequently - to clear (set to zero) bits 0 & 1 of a variable, -while leaving the rest of the variable unchanged, use the compound -bitwise AND operator (&=) with the constant B11111100 - -:: - - 1 0 1 0 1 0 1 0 variable - 1 1 1 1 1 1 0 0 mask - ---------------------- - 1 0 1 0 1 0 0 0 - - variable unchanged - bits cleared - - -Here is the same representation with the variable's bits replaced -with the symbol x - - - -:: - - x x x x x x x x variable - 1 1 1 1 1 1 0 0 mask - ---------------------- - x x x x x x 0 0 - - variable unchanged - bits cleared - - -So if: - -:: - - myByte = 10101010; - - myByte &= B1111100 == B10101000; - - - -compound bitwise OR (\|=) -========================= - -Description ------------ - -The compound bitwise OR operator (\|=) is often used with a -variable and a constant to "set" (set to 1) particular bits in a -variable. - - - -Syntax: -------- - -:: - - x |= y; // equivalent to x = x | y; - - - -Parameters ----------- - -x: a char, int or long variable -y: an integer constant or char, int, or long - - - -Example: --------- - -First, a review of the Bitwise OR (\|) operator - -:: - - 0 0 1 1 operand1 - 0 1 0 1 operand2 - ---------- - 0 1 1 1 (operand1 | operand2) - returned result - -Bits that are "bitwise ORed" with 0 are unchanged, so if myByte is -a byte variable, -myByte \| B00000000 = myByte; - - - -Bits that are "bitwise ORed" with 1 are set to 1 so: -myByte & B11111111 = B11111111; - - - -Consequently - to set bits 0 & 1 of a variable, while leaving the -rest of the variable unchanged, use the compound bitwise AND -operator (&=) with the constant B00000011 - -:: - - 1 0 1 0 1 0 1 0 variable - 0 0 0 0 0 0 1 1 mask - ---------------------- - 1 0 1 0 1 0 1 1 - - variable unchanged - bits set - - -Here is the same representation with the variables bits replaced -with the symbol x - - - -:: - - x x x x x x x x variable - 0 0 0 0 0 0 1 1 mask - ---------------------- - x x x x x x 1 1 - - variable unchanged - bits set - -So if: - -:: - - myByte = B10101010; - - myByte |= B00000011 == B10101011; - - - -See Also - - -- `& <http://arduino.cc/en/Reference/BitwiseAnd>`_ (bitwise AND) -- `\| <http://arduino.cc/en/Reference/BitwiseAnd>`_ (bitwise OR) -- `&& <http://arduino.cc/en/Reference/Boolean>`_ (Boolean AND) -- `\|\| <http://arduino.cc/en/Reference/Boolean>`_ (Boolean OR) - - diff --git a/docs/source/arduino/bitwisexornot.rst b/docs/source/arduino/bitwisexornot.rst deleted file mode 100644 index 25389cb..0000000 --- a/docs/source/arduino/bitwisexornot.rst +++ /dev/null @@ -1,51 +0,0 @@ -.. _arduino-bitwisexornot: - -Bitwise NOT (~) -=============== - -The bitwise NOT operator in C++ is the tilde character ~. Unlike & -and \|, the bitwise NOT operator is applied to a single operand to -its right. Bitwise NOT changes each bit to its opposite: 0 becomes -1, and 1 becomes 0. For example: - - - -:: - - 0 1 operand1 - - - -:: - - ---------- - 1 0 ~ operand1 - - - -:: - - int a = 103; // binary: 0000000001100111 - int b = ~a; // binary: 1111111110011000 = -104 - - - -You might be surprised to see a negative number like -104 as the -result of this operation. This is because the highest bit in an int -variable is the so-called sign bit. If the highest bit is 1, the -number is interpreted as negative. This encoding of positive and -negative numbers is referred to as two's complement. For more -information, see the Wikipedia article on -`two's complement. <http://en.wikipedia.org/wiki/Twos_complement>`_ - - - -As an aside, it is interesting to note that for any integer x, ~x -is the same as -x-1. - - - -At times, the sign bit in a signed integer expression can cause -some unwanted surprises. - - diff --git a/docs/source/arduino/bitwrite.rst b/docs/source/arduino/bitwrite.rst deleted file mode 100644 index 5d95506..0000000 --- a/docs/source/arduino/bitwrite.rst +++ /dev/null @@ -1,52 +0,0 @@ -.. _arduino-bitwrite: - -bitWrite() -========== - -Description ------------ - -Writes a bit of a numeric variable. - - - -Syntax ------- - -bitWrite(x, n, b) - - - -Parameters ----------- - -x: the numeric variable to which to write - - - -n: which bit of the number to write, starting at 0 for the -least-significant (rightmost) bit - - - -b: the value to write to the bit (0 or 1) - - - -Returns -------- - -none - - - -See also --------- - - -- `bit <http://arduino.cc/en/Reference/Bit>`_\ () -- `bitRead <http://arduino.cc/en/Reference/BitRead>`_\ () -- `bitSet <http://arduino.cc/en/Reference/BitSet>`_\ () -- `bitClear <http://arduino.cc/en/Reference/BitClear>`_\ () - - diff --git a/docs/source/arduino/boolean.rst b/docs/source/arduino/boolean.rst deleted file mode 100644 index f109bdb..0000000 --- a/docs/source/arduino/boolean.rst +++ /dev/null @@ -1,94 +0,0 @@ -.. _arduino-boolean: - -Boolean Operators -================= - -These can be used inside the condition of an -`if <http://arduino.cc/en/Reference/If>`_ statement. - - - -&& (logical and) -~~~~~~~~~~~~~~~~ - -True only if both operands are true, e.g. - -:: - - if (digitalRead(2) == HIGH && digitalRead(3) == HIGH) { // read two switches - // ... - } - -is true only if both inputs are high. - - - -\|\| (logical or) -~~~~~~~~~~~~~~~~~ - -True if either operand is true, e.g. - -:: - - if (x > 0 || y > 0) { - // ... - } - -is true if either x or y is greater than 0. - - - -! (not) -~~~~~~~ - -True if the operand is false, e.g. - -:: - - if (!x) { - // ... - } - -is true if x is false (i.e. if x equals 0). - - - -Warning -------- - -Make sure you don't mistake the boolean AND operator, && (double -ampersand) for the bitwise AND operator & (single ampersand). They -are entirely different beasts. - - - -Similarly, do not confuse the boolean \|\| (double pipe) operator -with the bitwise OR operator \| (single pipe). - - - -The bitwise not ~ (tilde) looks much different than the boolean not -! (exclamation point or "bang" as the programmers say) but you -still have to be sure which one you want where. - - - -Examples --------- - -:: - - if (a >= 10 && a <= 20){} // true if a is between 10 and 20 - - - -See also --------- - - -- `& <http://arduino.cc/en/Reference/BitwiseAnd>`_ (bitwise AND) -- `\| <http://arduino.cc/en/Reference/BitwiseAnd>`_ (bitwise OR) -- `~ <http://arduino.cc/en/Reference/BitwiseXorNot>`_ (bitwise NOT -- `if <http://arduino.cc/en/Reference/If>`_ - - diff --git a/docs/source/arduino/booleanvariables.rst b/docs/source/arduino/booleanvariables.rst deleted file mode 100644 index 3bbe72a..0000000 --- a/docs/source/arduino/booleanvariables.rst +++ /dev/null @@ -1,53 +0,0 @@ -.. _arduino-booleanvariables: - -boolean -======= - -A **boolean** holds one of two values, -`true <http://arduino.cc/en/Reference/Constants>`_ or -`false <http://arduino.cc/en/Reference/Constants>`_. (Each boolean -variable occupies one byte of memory.) - - - -Example -------- - -:: - - int LEDpin = 5; // LED on pin 5 - int switchPin = 13; // momentary switch on 13, other side connected to ground - - boolean running = false; - - void setup() - { - pinMode(LEDpin, OUTPUT); - pinMode(switchPin, INPUT); - digitalWrite(switchPin, HIGH); // turn on pullup resistor - } - - void loop() - { - if (digitalRead(switchPin) == LOW) - { // switch is pressed - pullup keeps pin high normally - delay(100); // delay to debounce switch - running = !running; // toggle running variable - digitalWrite(LEDpin, running) // indicate via LED - } - } - - - - - - -See also --------- - - -- `constants <http://arduino.cc/en/Reference/Constants>`_ -- `boolean operators <http://arduino.cc/en/Reference/Boolean>`_ -- `Variable Declaration <http://arduino.cc/en/Reference/VariableDeclaration>`_ - - diff --git a/docs/source/arduino/braces.rst b/docs/source/arduino/braces.rst deleted file mode 100644 index c7bd148..0000000 --- a/docs/source/arduino/braces.rst +++ /dev/null @@ -1,113 +0,0 @@ -.. _arduino-braces: - -{} Curly Braces -=============== - -Curly braces (also referred to as just "braces" or as "curly -brackets") are a major part of the C programming language. They are -used in several different constructs, outlined below, and this can -sometimes be confusing for beginners. - - - -An opening curly brace "{" must always be followed by a closing -curly brace "}". This is a condition that is often referred to as -the braces being balanced. The Arduino IDE (integrated development -environment) includes a convenient feature to check the balance of -curly braces. Just select a brace, or even click the insertion -point immediately following a brace, and its logical companion will -be highlighted. - - - -At present this feature is slightly buggy as the IDE will often -find (incorrectly) a brace in text that has been "commented out." - - - -Beginning programmers, and programmers coming to C from the BASIC -language often find using braces confusing or daunting. After all, -the same curly braces replace the RETURN statement in a subroutine -(function), the ENDIF statement in a conditional and the NEXT -statement in a FOR loop. - - - -Because the use of the curly brace is so varied, it is good -programming practice to type the closing brace immediately after -typing the opening brace when inserting a construct which requires -curly braces. Then insert some carriage returns between your braces -and begin inserting statements. Your braces, and your attitude, -will never become unbalanced. - - - -Unbalanced braces can often lead to cryptic, impenetrable compiler -errors that can sometimes be hard to track down in a large program. -Because of their varied usages, braces are also incredibly -important to the syntax of a program and moving a brace one or two -lines will often dramatically affect the meaning of a program. - - - -**The main uses of curly braces** ---------------------------------- - -Functions ---------- - -:: - - void myfunction(datatype argument){ - statements(s) - } - - - -Loops ------ - -:: - - while (boolean expression) - { - statement(s) - } - - do - { - statement(s) - } while (boolean expression); - - for (initialisation; termination condition; incrementing expr) - { - statement(s) - } - - - -Conditional statements ----------------------- - - - -:: - - if (boolean expression) - { - statement(s) - } - - else if (boolean expression) - { - statement(s) - } - else - { - statement(s) - } - - - -`Reference Home <http://arduino.cc/en/Reference/HomePage>`_ - diff --git a/docs/source/arduino/break.rst b/docs/source/arduino/break.rst deleted file mode 100644 index d951c52..0000000 --- a/docs/source/arduino/break.rst +++ /dev/null @@ -1,28 +0,0 @@ -.. _arduino-break: - -break -===== - -**break** is used to exit from a **do**, **for**, or **while** -loop, bypassing the normal loop condition. It is also used to exit -from a **switch** statement. - - - -Example -------- - -:: - - for (x = 0; x < 255; x ++) - { - digitalWrite(PWMpin, x); - sens = analogRead(sensorPin); - if (sens > threshold){ // bail out on sensor detect - x = 0; - break; - } - delay(50); - } - - diff --git a/docs/source/arduino/byte.rst b/docs/source/arduino/byte.rst deleted file mode 100644 index 5e94bd4..0000000 --- a/docs/source/arduino/byte.rst +++ /dev/null @@ -1,29 +0,0 @@ -.. _arduino-byte: - -byte -==== - -Description ------------ - -A byte stores an 8-bit unsigned number, from 0 to 255. - - - -Example -------- - -:: - - byte b = B10010; // "B" is the binary formatter (B10010 = 18 decimal) - - - -See also --------- - - -- `word <http://arduino.cc/en/Reference/Word>`_ -- `byte <http://arduino.cc/en/Reference/ByteCast>`_\ () -- `Variable Declaration <http://arduino.cc/en/Reference/VariableDeclaration>`_ - diff --git a/docs/source/arduino/bytecast.rst b/docs/source/arduino/bytecast.rst deleted file mode 100644 index 71ab4aa..0000000 --- a/docs/source/arduino/bytecast.rst +++ /dev/null @@ -1,41 +0,0 @@ -.. _arduino-bytecast: - -byte() -====== - -Description ------------ - -Converts a value to the -`byte <http://arduino.cc/en/Reference/Byte>`_ data type. - - - -Syntax ------- - -byte(x) - - - -Parameters ----------- - -x: a value of any type - - - -Returns -------- - -byte - - - -See also --------- - - -- `byte <http://arduino.cc/en/Reference/Byte>`_ - - diff --git a/docs/source/arduino/changes.rst b/docs/source/arduino/changes.rst deleted file mode 100644 index 75cd65d..0000000 --- a/docs/source/arduino/changes.rst +++ /dev/null @@ -1,93 +0,0 @@ -.. _arduino-changes: - -Changes -======= - -This page lists major changes to the Arduino core, libraries, and -environment. For details, see the -`release notes <http://arduino.cc/en/Main/ReleaseNotes>`_. - - - -Changes in Arduino 0017 -~~~~~~~~~~~~~~~~~~~~~~~ - - -- **Environment**: The code base for the Arduino development - environment was largely re-written to bring it back into sync with - Processing (1.0.3). The main differences include support for - multiple sketch windows open simultaneously and a dedicated window - for the serial monitor. - - -- **Icons**: The icons and about images were updated. - - -- **Arduino.app**: The Mac OS X version of Arduino is now a .app - file packaged in a .dmg. - - -- **Libraries**: Support was added for third-party libraries in - the *SKETCHBOOK*/libraries directory. This allows user-installed - libraries to persist across upgrades of the Arduino software. - - -- **Servo**: The servo library was rewritten to allow support for - up to 12 servos (on any pins) and up to 48 on the Mega. - - -- **LiquidCrystal**: The begin(), cursor(), noCursor(), blink(), - noBlink(), display(), noDisplay(), scrollDisplayLeft(), - scrollDisplayRight(), autoscroll(), noAutoscroll(), leftToRight(), - rightToLeft(), and createChar() functions were added. - - - -Changes in Arduino 0016 -~~~~~~~~~~~~~~~~~~~~~~~ - - -- New functions for writing a string, write(str), or buffer, - write(buf, len), were added to the Print, Serial, and Ethernet - library Client and Server classes. - - - -Changes in Arduino 0015 -~~~~~~~~~~~~~~~~~~~~~~~ - - -- Support for the Arduino Mega. - - - -Changes in Arduino 0013 -~~~~~~~~~~~~~~~~~~~~~~~ - - -- Support for printing floats was added to the Print, Serial, and - Ethernet library Client and Server classes. - - -- The word type and word(), bitRead(), bitWrite(), bitSet(), - bitClear(), bit(), lowByte(), and highByte() functions were added. - - - -Changes in Arduino 0012 -~~~~~~~~~~~~~~~~~~~~~~~ - - -- Added the Firmata library, which provides a standard protocol - for serial communication. - - -- Added Ethernet library. - - -- Added Servo library. - - -- Added LiquidCrystal library. - - diff --git a/docs/source/arduino/char.rst b/docs/source/arduino/char.rst deleted file mode 100644 index e783ed6..0000000 --- a/docs/source/arduino/char.rst +++ /dev/null @@ -1,51 +0,0 @@ -.. _arduino-char: - -char -==== - -Description ------------ - -A data type that takes up 1 byte of memory that stores a character -value. Character literals are written in single quotes, like this: -'A' (for multiple characters - strings - use double quotes: -"ABC"). - - - -Characters are stored as numbers however. You can see the specific -encoding in the -`ASCII chart <http://arduino.cc/en/Reference/ASCIIchart>`_. This -means that it is possible to do arithmetic on characters, in which -the ASCII value of the character is used (e.g. 'A' + 1 has the -value 66, since the ASCII value of the capital letter A is 65). See -`Serial.println <http://arduino.cc/en/Serial/Println>`_ reference -for more on how characters are translated to numbers. - - - -The char datatype is a signed type, meaning that it encodes numbers -from -128 to 127. For an unsigned, one-byte (8 bit) data type, use -the *byte* data type. - - - -Example -------- - -:: - - char myChar = 'A'; - char myChar = 65; // both are equivalent - - - -See also --------- - - -- `byte <http://arduino.cc/en/Reference/Byte>`_ -- `int <http://arduino.cc/en/Reference/Int>`_ -- `array <http://arduino.cc/en/Reference/Array>`_ -- `Serial.println <http://arduino.cc/en/Serial/Println>`_ - diff --git a/docs/source/arduino/charcast.rst b/docs/source/arduino/charcast.rst deleted file mode 100644 index daa7c92..0000000 --- a/docs/source/arduino/charcast.rst +++ /dev/null @@ -1,41 +0,0 @@ -.. _arduino-charcast: - -char() -====== - -Description ------------ - -Converts a value to the -`char <http://arduino.cc/en/Reference/Char>`_ data type. - - - -Syntax ------- - -char(x) - - - -Parameters ----------- - -x: a value of any type - - - -Returns -------- - -char - - - -See also --------- - - -- `char <http://arduino.cc/en/Reference/Char>`_ - - diff --git a/docs/source/arduino/comments.rst b/docs/source/arduino/comments.rst deleted file mode 100644 index 189ead5..0000000 --- a/docs/source/arduino/comments.rst +++ /dev/null @@ -1,45 +0,0 @@ -.. _arduino-comments: - -Comments -======== - -Comments are lines in the program that are used to inform yourself -or others about the way the program works. They are ignored by the -compiler, and not exported to the processor, so they don't take up -any space on the Atmega chip. - - - -Comments only purpose are to help you understand (or remember) how -your program works or to inform others how your program works. -There are two different ways of marking a line as a comment: - - - -Example -------- - -:: - - x = 5; // This is a single line comment. Anything after the slashes is a comment - // to the end of the line - - /* this is multiline comment - use it to comment out whole blocks of code - - if (gwb == 0){ // single line comment is OK inside a multiline comment - x = 3; /* but not another multiline comment - this is invalid */ - } - // don't forget the "closing" comment - they have to be balanced! - */ - - - -**Tip** -When experimenting with code, "commenting out" parts of your -program is a convenient way to remove lines that may be buggy. This -leaves the lines in the code, but turns them into comments, so the -compiler just ignores them. This can be especially useful when -trying to locate a problem, or when a program refuses to compile -and the compiler error is cryptic or unhelpful. - - diff --git a/docs/source/arduino/comparison.rst b/docs/source/arduino/comparison.rst deleted file mode 100644 index b87e05b..0000000 --- a/docs/source/arduino/comparison.rst +++ /dev/null @@ -1,54 +0,0 @@ -.. _arduino-comparison: - -Arduino/Processing Language Comparison -====================================== - -The Arduino language (based on Wiring) is implemented in C/C++, and -therefore has some differences from the Processing language, which -is based on Java. - - - -Arrays -~~~~~~ - -*Arduino* -*Processing* -int bar[8]; -bar[0] = 1; -int[] bar = new int[8]; -bar[0] = 1; -int foo[] = { 0, 1, 2 }; -int foo[] = { 0, 1, 2 }; -*or* -int[] foo = { 0, 1, 2 }; - - -Loops -~~~~~ - -*Arduino* -*Processing* -int i; -for (i = 0; i < 5; i++) { ... } -for (int i = 0; i < 5; i++) { ... } - - -Printing -~~~~~~~~ - -*Arduino* -*Processing* -Serial.println("hello world"); -println("hello world"); -int i = 5; -Serial.println(i); -int i = 5; -println(i); -int i = 5; -Serial.print("i = "); -Serial.print(i); -Serial.println(); -int i = 5; -println("i = " + i); - diff --git a/docs/source/arduino/const.rst b/docs/source/arduino/const.rst deleted file mode 100644 index 295b817..0000000 --- a/docs/source/arduino/const.rst +++ /dev/null @@ -1,55 +0,0 @@ -.. _arduino-const: - -const keyword -============= - -The **const** keyword stands for constant. It is a variable -*qualifier* that modifies the behavior of the variable, making a -variable "*read-only*". This means that the variable can be used -just as any other variable of its type, but its value cannot be -changed. You will get a compiler error if you try to assign a value -to a **const** variable. - - - -Constants defined with the *const* keyword obey the rules of -*`variable scoping <http://arduino.cc/en/Reference/Scope>`_* that -govern other variables. This, and the pitfalls of using*#define*, -makes the *const* keyword a superior method for defining constants -and is preferred over using -*`#define <http://arduino.cc/en/Reference/Define>`_*. - - - -Example -------- - -:: - - const float pi = 3.14; - float x; - - // .... - - x = pi * 2; // it's fine to use const's in math - - pi = 7; // illegal - you can't write to (modify) a constant - - -**#define** or **const** ------------------------- - -You can use either **const** or **#define** for creating numeric or -string constants. For -`arrays <http://arduino.cc/en/Reference/Array>`_, you will need to -use **const**. In general *const* is preferred over *#define* for -defining constants. - - - -See also: - - -- `#define <http://arduino.cc/en/Reference/Define>`_ -- `volatile <http://arduino.cc/en/Reference/Volatile>`_ - diff --git a/docs/source/arduino/constants.rst b/docs/source/arduino/constants.rst deleted file mode 100644 index 49f3933..0000000 --- a/docs/source/arduino/constants.rst +++ /dev/null @@ -1,144 +0,0 @@ -.. _arduino-constants: - -constants -========= - -Constants are predefined variables in the Arduino language. They -are used to make the programs easier to read. We classify constants -in groups. - - - -Defining Logical Levels, true and false (Boolean Constants) -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -There are two constants used to represent truth and falsity in the -Arduino language: **true**, and **false**. - - - -false ------ - -false is the easier of the two to define. false is defined as 0 -(zero). - - - -true ----- - -true is often said to be defined as 1, which is correct, but true -has a wider definition. Any integer which is *non-zero* is TRUE, in -a Boolean sense. So -1, 2 and -200 are all defined as true, too, in -a Boolean sense. - - - -Note that the *true* and *false* constants are typed in lowercase -unlike HIGH, LOW, INPUT, & OUTPUT. - - - -Defining Pin Levels, HIGH and LOW -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -When reading or writing to a digital pin there are only two -possible values a pin can take/be-set-to: **HIGH** and **LOW**. - - - -**HIGH** - - - -The meaning of HIGH (in reference to a pin) is somewhat different -depending on whether a pin is set to an INPUT or OUTPUT. When a pin -is configured as an INPUT with pinMode, and read with digitalRead, -the microcontroller will report HIGH if a voltage of 3 volts or -more is present at the pin. - - - -A pin may also be configured as an INPUT with pinMode, and -subsequently made HIGH with digitalWrite, this will set the -internal 20K pullup resistors, which will *steer* the input pin to -a HIGH reading unless it is pulled LOW by external circuitry. - - - -When a pin is configured to OUTPUT with pinMode, and set to HIGH -with digitalWrite, the pin is at 5 volts. In this state it can -*source* current, e.g. light an LED that is connected through a -series resistor to ground, or to another pin configured as an -output, and set to LOW. - - - -**LOW** - - - -The meaning of LOW also has a different meaning depending on -whether a pin is set to INPUT or OUTPUT. When a pin is configured -as an INPUT with pinMode, and read with digitalRead, the -microcontroller will report LOW if a voltage of 2 volts or less is -present at the pin. - - - -When a pin is configured to OUTPUT with pinMode, and set to LOW -with digitalWrite, the pin is at 0 volts. In this state it can -*sink* current, e.g. light an LED that is connected through a -series resistor to, +5 volts, or to another pin configured as an -output, and set to HIGH. - - - -Defining Digital Pins, INPUT and OUTPUT -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Digital pins can be used either as **INPUT** or **OUTPUT**. -Changing a pin from INPUT TO OUTPUT with pinMode() drastically -changes the electrical behavior of the pin. - - - -Pins Configured as Inputs -------------------------- - -Arduino (Atmega) pins configured as **INPUT** with pinMode() are -said to be in a high-impedance state. One way of explaining this is -that pins configured as INPUT make extremely small demands on the -circuit that they are sampling, say equivalent to a series resistor -of 100 Megohms in front of the pin. This makes them useful for -reading a sensor, but not powering an LED. - - - -Pins Configured as Outputs --------------------------- - -Pins configured as **OUTPUT** with pinMode() are said to be in a -low-impedance state. This means that they can provide a substantial -amount of current to other circuits. Atmega pins can source -(provide positive current) or sink (provide negative current) up to -40 mA (milliamps) of current to other devices/circuits. This makes -them useful for powering LED's but useless for reading sensors. -Pins configured as outputs can also be damaged or destroyed if -short circuited to either ground or 5 volt power rails. The amount -of current provided by an Atmega pin is also not enough to power -most relays or motors, and some interface circuitry will be -required. - - - -See also --------- - - -- `pinMode() <http://arduino.cc/en/Reference/PinMode>`_ -- `Integer Constants <http://arduino.cc/en/Reference/IntegerConstants>`_ -- `boolean variables <http://arduino.cc/en/Reference/BooleanVariables>`_ - - diff --git a/docs/source/arduino/constrain.rst b/docs/source/arduino/constrain.rst deleted file mode 100644 index 2769219..0000000 --- a/docs/source/arduino/constrain.rst +++ /dev/null @@ -1,60 +0,0 @@ -.. _arduino-constrain: - -constrain(x, a, b) -================== - -Description ------------ - -Constrains a number to be within a range. - - - -Parameters ----------- - -x: the number to constrain, all data types - - - -a: the lower end of the range, all data types - - - -b: the upper end of the range, all data types - - - -Returns -------- - -**x**: if **x** is between **a** and **b** - - - -**a**: if **x** is less than **a** - - - -**b**: if **x** is greater than **b** - - - -Example -------- - -:: - - sensVal = constrain(sensVal, 10, 150); - // limits range of sensor values to between 10 and 150 - - - -See also --------- - - -- `min <http://arduino.cc/en/Reference/Min>`_\ () -- `max <http://arduino.cc/en/Reference/Max>`_\ () - - diff --git a/docs/source/arduino/continue.rst b/docs/source/arduino/continue.rst deleted file mode 100644 index 66c7e60..0000000 --- a/docs/source/arduino/continue.rst +++ /dev/null @@ -1,29 +0,0 @@ -.. _arduino-continue: - -continue -======== - -The continue statement skips the rest of the current iteration of a -loop (**do**, **for**, or **while**). It continues by checking the -conditional expression of the loop, and proceeding with any -subsequent iterations. - - - -Example -------- - -:: - - - for (x = 0; x < 255; x ++) - { - if (x > 40 && x < 120){ // create jump in values - continue; - } - - digitalWrite(PWMpin, x); - delay(50); - } - - diff --git a/docs/source/arduino/cos.rst b/docs/source/arduino/cos.rst deleted file mode 100644 index 7fed4bb..0000000 --- a/docs/source/arduino/cos.rst +++ /dev/null @@ -1,33 +0,0 @@ -.. _arduino-cos: - -cos(rad) -======== - -Description ------------ - -Calculates the cos of an angle (in radians). The result will be -between -1 and 1. - -Parameters ----------- - -rad: the angle in radians (*float*) - - - -Returns -------- - -The cos of the angle ("double") - - - -See also --------- - - -- `sin <http://arduino.cc/en/Reference/Sin>`_\ () -- `tan <http://arduino.cc/en/Reference/Tan>`_\ () -- `float <http://arduino.cc/en/Reference/Float>`_ -- `double <http://arduino.cc/en/Reference/Double>`_ diff --git a/docs/source/arduino/define.rst b/docs/source/arduino/define.rst deleted file mode 100644 index 6190cb9..0000000 --- a/docs/source/arduino/define.rst +++ /dev/null @@ -1,83 +0,0 @@ -.. _arduino-define: - -Define -====== - -``#define`` is a useful C component that allows the programmer to -give a name to a constant value before the program is compiled. -Defined constants in arduino don't take up any program memory space -on the chip. The compiler will replace references to these -constants with the defined value at compile time. - - - -This can have some unwanted side effects though, if for example, a -constant name that had been #defined is included in some other -constant or variable name. In that case the text would be replaced -by the #defined number (or text). - - - -In general, the *`const <http://arduino.cc/en/Reference/Const>`_* -keyword is preferred for defining constants and should be used -instead of #define. - - - -Arduino defines have the same syntax as C defines: - - - -Syntax ------- - -``#define constantName value`` - - - -Note that the # is necessary. - - - -Example -------- - -:: - - #define ledPin 3 - // The compiler will replace any mention of ledPin with the value 3 at compile time. - - - -Tip ---- - -There is no semicolon after the #define statement. If you include -one, the compiler will throw cryptic errors further down the page. - - - -:: - - #define ledPin 3; // this is an error - - - -Similarly, including an equal sign after the #define statement will -also generate a cryptic compiler error further down the page. - - - -:: - - #define ledPin = 3 // this is also an error - - - -See ---- - - -- `const <http://arduino.cc/en/Reference/Const>`_ -- `Constants <http://arduino.cc/en/Reference/IntegerConstants>`_ - diff --git a/docs/source/arduino/delay.rst b/docs/source/arduino/delay.rst deleted file mode 100644 index 973c75b..0000000 --- a/docs/source/arduino/delay.rst +++ /dev/null @@ -1,94 +0,0 @@ -.. _arduino-delay: - -delay() -======= - -Description ------------ - -Pauses the program for the amount of time (in miliseconds) -specified as parameter. (There are 1000 milliseconds in a second.) - - - -Syntax ------- - -delay(ms) - - - -Parameters ----------- - -ms: the number of milliseconds to pause (*unsigned long*) - - - -Returns -------- - -nothing - - - -Example -------- - -:: - - int ledPin = 13; // LED connected to digital pin 13 - - void setup() - { - pinMode(ledPin, OUTPUT); // sets the digital pin as output - } - - void loop() - { - digitalWrite(ledPin, HIGH); // sets the LED on - delay(1000); // waits for a second - digitalWrite(ledPin, LOW); // sets the LED off - delay(1000); // waits for a second - } - - - -Caveat ------- - -While it is easy to create a blinking LED with the delay() -function, and many sketches use short delays for such tasks as -switch debouncing, the use of delay() in a sketch has significant -drawbacks. No other reading of sensors, mathematical calculations, -or pin manipulation can go on during the delay function, so in -effect, it brings most other activity to a halt. For alternative -approaches to controlling timing see the -`millis() <http://arduino.cc/en/Reference/Millis>`_ function and -the sketch sited below. More knowledgeable programmers usually -avoid the use of delay() for timing of events longer than 10's of -milliseconds unless the Arduino sketch is very simple. - - - -Certain things *do* go on while the delay() function is controlling -the Atmega chip however, because the delay function does not -disable interrupts. Serial communication that appears at the RX pin -is recorded, PWM -(`analogWrite <http://arduino.cc/en/Reference/AnalogWrite>`_) -values and pin states are maintained, and -`interrupts <http://arduino.cc/en/Reference/AttachInterrupt>`_ will -work as they should. - - - -See also --------- - - -- `millis <http://arduino.cc/en/Reference/Millis>`_\ () -- `micros <http://arduino.cc/en/Reference/Micros>`_\ () -- `delayMicroseconds <http://arduino.cc/en/Reference/DelayMicroseconds>`_\ () -- `Blink Without Delay <http://arduino.cc/en/Tutorial/BlinkWithoutDelay>`_ - example - diff --git a/docs/source/arduino/delaymicroseconds.rst b/docs/source/arduino/delaymicroseconds.rst deleted file mode 100644 index 0feaba7..0000000 --- a/docs/source/arduino/delaymicroseconds.rst +++ /dev/null @@ -1,93 +0,0 @@ -.. _arduino-delaymicroseconds: - -delayMicroseconds() -=================== - -Description ------------ - -Pauses the program for the amount of time (in microseconds) -specified as parameter. There are a thousand microseconds in a -millisecond, and a million microseconds in a second. - - - -Currently, the largest value that will produce an accurate delay is -16383. This could change in future Arduino releases. For delays -longer than a few thousand microseconds, you should use delay() -instead. - - - -Syntax ------- - -delayMicroseconds(us) - - - -Parameters ----------- - -us: the number of microseconds to pause (*unsigned int*) - - - -Returns -------- - -None - - - -Example -------- - -:: - - - int outPin = 8; // digital pin 8 - - void setup() - { - pinMode(outPin, OUTPUT); // sets the digital pin as output - } - - void loop() - { - digitalWrite(outPin, HIGH); // sets the pin on - delayMicroseconds(50); // pauses for 50 microseconds - digitalWrite(outPin, LOW); // sets the pin off - delayMicroseconds(50); // pauses for 50 microseconds - } - - - -configures pin number 8 to work as an output pin. It sends a train -of pulses with 100 microseconds period. - - - -Caveats and Known Issues ------------------------- - -This function works very accurately in the range 3 microseconds and -up. We cannot assure that delayMicroseconds will perform precisely -for smaller delay-times. - - - -As of Arduino 0018, delayMicroseconds() no longer disables -interrupts. - - - -See also --------- - - -- `millis <http://arduino.cc/en/Reference/Millis>`_\ () -- `micros <http://arduino.cc/en/Reference/Micros>`_\ () -- `delay <http://arduino.cc/en/Reference/Delay>`_\ () - - diff --git a/docs/source/arduino/detachinterrupt.rst b/docs/source/arduino/detachinterrupt.rst deleted file mode 100644 index f0342df..0000000 --- a/docs/source/arduino/detachinterrupt.rst +++ /dev/null @@ -1,26 +0,0 @@ -.. _arduino-detachinterrupt: - -detachInterrupt(interrupt) -========================== - -Description ------------ - -Turns off the given interrupt. - - - -Parameters ----------- - -interrupt: the number of interrupt to disable (0 or 1). - - - -See also --------- - - -- `attachInterrupt <http://arduino.cc/en/Reference/AttachInterrupt>`_\ () - - diff --git a/docs/source/arduino/digitalread.rst b/docs/source/arduino/digitalread.rst deleted file mode 100644 index ec64fb0..0000000 --- a/docs/source/arduino/digitalread.rst +++ /dev/null @@ -1,86 +0,0 @@ -.. _arduino-digitalread: - -digitalRead() -============= - -Description ------------ - -Reads the value from a specified digital pin, either -`HIGH <http://arduino.cc/en/Reference/Constants>`_ or -`LOW <http://arduino.cc/en/Reference/Constants>`_. - - - -Syntax ------- - -digitalRead(pin) - - - -Parameters ----------- - -pin: the number of the digital pin you want to read (*int*) - - - -Returns -------- - -`HIGH <http://arduino.cc/en/Reference/Constants>`_ or -`LOW <http://arduino.cc/en/Reference/Constants>`_ - - - -Example -------- - -:: - - - int ledPin = 13; // LED connected to digital pin 13 - int inPin = 7; // pushbutton connected to digital pin 7 - int val = 0; // variable to store the read value - - void setup() - { - pinMode(ledPin, OUTPUT); // sets the digital pin 13 as output - pinMode(inPin, INPUT); // sets the digital pin 7 as input - } - - void loop() - { - val = digitalRead(inPin); // read the input pin - digitalWrite(ledPin, val); // sets the LED to the button's value - } - - - -Sets pin 13 to the same value as the pin 7, which is an input. - - - -Note ----- - -If the pin isn't connected to anything, digitalRead() can return -either HIGH or LOW (and this can change randomly). - - - -The analog input pins can be used as digital pins, referred to as -A0, A1, etc. - - - -See also --------- - - -- `pinMode <http://arduino.cc/en/Reference/PinMode>`_\ () -- `digitalWrite <http://arduino.cc/en/Reference/DigitalWrite>`_\ () -- `Tutorial: Digital Pins <http://arduino.cc/en/Tutorial/DigitalPins>`_ - - diff --git a/docs/source/arduino/digitalwrite.rst b/docs/source/arduino/digitalwrite.rst deleted file mode 100644 index 82e1813..0000000 --- a/docs/source/arduino/digitalwrite.rst +++ /dev/null @@ -1,113 +0,0 @@ -.. _arduino-digitalwrite: - -digitalWrite() -============== - -Description ------------ - -Write a `HIGH <http://arduino.cc/en/Reference/Constants>`_ or a -`LOW <http://arduino.cc/en/Reference/Constants>`_ value to a -digital pin. - - - -If the pin has been configured as an OUTPUT with -`pinMode <http://arduino.cc/en/Reference/PinMode>`_\ (), its voltage -will be set to the corresponding value: 5V (or 3.3V on 3.3V boards) -for HIGH, 0V (ground) for LOW. - - - -If the pin is configured as an INPUT, writing a HIGH value with -digitalWrite() will enable an internal 20K pullup resistor (see the -`tutorial on digital pins <http://arduino.cc/en/Tutorial/DigitalPins>`_). -Writing LOW will disable the pullup. The pullup resistor is enough -to light an LED dimly, so if LEDs appear to work, but very dimly, -this is a likely cause. The remedy is to set the pin to an output -with the pinMode() function. - - - -**NOTE:** Digital pin 13 is harder to use as a digital input than -the other digital pins because it has an LED and resistor attached -to it that's soldered to the board on most boards. If you enable -its internal 20k pull-up resistor, it will hang at around 1.7 V -instead of the expected 5V because the onboard LED and series -resistor pull the voltage level down, meaning it always returns -LOW. If you must use pin 13 as a digital input, use an external -pull down resistor. - - - -Syntax ------- - -digitalWrite(pin, value) - - - -Parameters ----------- - -pin: the pin number - - - -value: `HIGH <http://arduino.cc/en/Reference/Constants>`_ or -`LOW <http://arduino.cc/en/Reference/Constants>`_ - - - -Returns -------- - -none - - - -Example -------- - -:: - - - int ledPin = 13; // LED connected to digital pin 13 - - void setup() - { - pinMode(ledPin, OUTPUT); // sets the digital pin as output - } - - void loop() - { - digitalWrite(ledPin, HIGH); // sets the LED on - delay(1000); // waits for a second - digitalWrite(ledPin, LOW); // sets the LED off - delay(1000); // waits for a second - } - - - -Sets pin 13 to HIGH, makes a one-second-long delay, and sets the -pin back to LOW. - - - -Note ----- - -The analog input pins can be used as digital pins, referred to as -A0, A1, etc. - - - -See also --------- - - -- `pinMode <http://arduino.cc/en/Reference/PinMode>`_\ () -- `digitalRead <http://arduino.cc/en/Reference/DigitalRead>`_\ () -- `Tutorial: Digital Pins <http://arduino.cc/en/Tutorial/DigitalPins>`_ - - diff --git a/docs/source/arduino/double.rst b/docs/source/arduino/double.rst deleted file mode 100644 index 4e7f20c..0000000 --- a/docs/source/arduino/double.rst +++ /dev/null @@ -1,32 +0,0 @@ -.. _arduino-double: - -double -====== - -Desciption ----------- - -Double precision floating point number. Occupies 4 bytes. - - - -The double implementation on the Arduino is currently exactly the -same as the float, with no gain in precision. - - - -Tip ---- - -Users who borrow code from other sources that includes double -variables may wish to examine the code to see if the implied -precision is different from that actually achieved on the Arduino. - - - -See: ----- - - -- `float <http://arduino.cc/en/Reference/Float>`_ - diff --git a/docs/source/arduino/dowhile.rst b/docs/source/arduino/dowhile.rst deleted file mode 100644 index 48fe75b..0000000 --- a/docs/source/arduino/dowhile.rst +++ /dev/null @@ -1,33 +0,0 @@ -.. _arduino-dowhile: - -do - while -========== - -The **do** loop works in the same manner as the **while** loop, -with the exception that the condition is tested at the end of the -loop, so the **do** loop will *always* run at least once. - - - -:: - - do - { - // statement block - } while (test condition); - - - -Example -------- - -:: - - do - { - delay(50); // wait for sensors to stabilize - x = readSensors(); // check the sensors - - } while (x < 100); - - diff --git a/docs/source/arduino/else.rst b/docs/source/arduino/else.rst deleted file mode 100644 index f278a0d..0000000 --- a/docs/source/arduino/else.rst +++ /dev/null @@ -1,73 +0,0 @@ -.. _arduino-else: - -if / else -========= - -**if/else** allows greater control over the flow of code than the -basic **if** statement, by allowing multiple tests to be grouped -together. For example, an analog input could be tested and one -action taken if the input was less than 500, and another action -taken if the input was 500 or greater. The code would look like -this: - - - -:: - - if (pinFiveInput < 500) - { - // action A - } - else - { - // action B - } - - - -**else** can proceed another **if** test, so that multiple, -mutually exclusive tests can be run at the same time. - - - -Each test will proceed to the next one until a true test is -encountered. When a true test is found, its associated block of -code is run, and the program then skips to the line following the -entire if/else construction. If no test proves to be true, the -default **else** block is executed, if one is present, and sets the -default behavior. - - - -Note that an **else if** block may be used with or without a -terminating **else** block and vice versa. An unlimited number of -such **else if** branches is allowed. - - - -:: - - if (pinFiveInput < 500) - { - // do Thing A - } - else if (pinFiveInput >= 1000) - { - // do Thing B - } - else - { - // do Thing C - } - -Another way to express branching, mutually exclusive tests, is with -the `switch case <http://arduino.cc/en/Reference/SwitchCase>`_ -statement. - - - -See also: ---------- - -`switch case <http://arduino.cc/en/Reference/SwitchCase>`_ - diff --git a/docs/source/arduino/float.rst b/docs/source/arduino/float.rst deleted file mode 100644 index 2f83a67..0000000 --- a/docs/source/arduino/float.rst +++ /dev/null @@ -1,88 +0,0 @@ -.. _arduino-float: - -float -===== - -Description ------------ - -Datatype for floating-point numbers, a number that has a decimal -point. Floating-point numbers are often used to approximate analog -and continuous values because they have greater resolution than -integers. Floating-point numbers can be as large as 3.4028235E+38 -and as low as -3.4028235E+38. They are stored as 32 bits (4 bytes) -of information. - - - -Floats have only 6-7 decimal digits of precision. That means the -total number of digits, not the number to the right of the decimal -point. Unlike other platforms, where you can get more precision by -using a double (e.g. up to 15 digits), on the Arduino, double is -the same size as float. - - - -Floating point numbers are not exact, and may yield strange results -when compared. For example ``6.0 / 3.0`` may not equal ``2.0``. You -should instead check that the absolute value of the difference -between the numbers is less than some small number. - - - -Floating point math is also much slower than integer math in -performing calculations, so should be avoided if, for example, a -loop has to run at top speed for a critical timing function. -Programmers often go to some lengths to convert floating point -calculations to integer math to increase speed. - - - -Examples --------- - -:: - - float myfloat; - float sensorCalbrate = 1.117; - - - -Syntax ------- - -:: - - float var = val; - - - - -- var - your float variable name -- val - the value you assign to that variable - - - -Example Code ------------- - -:: - - int x; - int y; - float z; - - x = 1; - y = x / 2; // y now contains 0, ints can't hold fractions - z = (float)x / 2.0; // z now contains .5 (you have to use 2.0, not 2) - - - -See Also --------- - - -- `int <http://arduino.cc/en/Reference/Int>`_ -- `double <http://arduino.cc/en/Reference/Double>`_ -- `Variable Declaration <http://arduino.cc/en/Reference/VariableDeclaration>`_ - diff --git a/docs/source/arduino/floatcast.rst b/docs/source/arduino/floatcast.rst deleted file mode 100644 index 6b85727..0000000 --- a/docs/source/arduino/floatcast.rst +++ /dev/null @@ -1,51 +0,0 @@ -.. _arduino-floatcast: - -float() -======= - -Description ------------ - -Converts a value to the -`float <http://arduino.cc/en/Reference/Float>`_ data type. - - - -Syntax ------- - -float(x) - - - -Parameters ----------- - -x: a value of any type - - - -Returns -------- - -float - - - -Notes ------ - -See the reference for -`float <http://arduino.cc/en/Reference/Float>`_ for details about -the precision and limitations of floating point numbers on -Arduino. - - - -See also --------- - - -- `float <http://arduino.cc/en/Reference/Float>`_ - - diff --git a/docs/source/arduino/for.rst b/docs/source/arduino/for.rst deleted file mode 100644 index b7e2e95..0000000 --- a/docs/source/arduino/for.rst +++ /dev/null @@ -1,117 +0,0 @@ -.. _arduino-for: - -for statements -============== - -Desciption ----------- - -The **for** statement is used to repeat a block of statements -enclosed in curly braces. An increment counter is usually used to -increment and terminate the loop. The **for** statement is useful -for any repetitive operation, and is often used in combination with -arrays to operate on collections of data/pins. - - - -There are three parts to the **for** loop header: - - - -``<strong>for</strong> (<strong>initialization</strong>;<strong> condition</strong>;<strong> increment</strong>) {`` - - - -``//statement(s);`` - - - -``}`` - -|image0| - - -The **initialization** happens first and exactly once. Each time -through the loop, the **condition** is tested; if it's true, the -statement block, and the **increment** is executed, then the -**condition** is tested again. When the **condition** becomes -false, the loop ends. - - - -Example -------- - -:: - - // Dim an LED using a PWM pin - int PWMpin = 10; // LED in series with 470 ohm resistor on pin 10 - - void setup() - { - // no setup needed - } - - void loop() - { - for (int i=0; i <= 255; i++){ - analogWrite(PWMpin, i); - delay(10); - } - } - - - -Coding Tips ------------ - -The C **for** loop is much more flexible than **for** loops found -in some other computer languages, including BASIC. Any or all of -the three header elements may be omitted, although the semicolons -are required. Also the statements for initialization, condition, -and increment can be any valid C statements with unrelated -variables, and use any C datatypes including floats. These types of -unusual **for** statements may provide solutions to some rare -programming problems. - - - -For example, using a multiplication in the increment line will -generate a logarithmic progression: - -:: - - for(int x = 2; x < 100; x = x * 1.5){ - println(x); - } - - - -Generates: 2,3,4,6,9,13,19,28,42,63,94 - - - -Another example, fade an LED up and down with one **for** loop: - - - -:: - - void loop() - { - int x = 1; - for (int i = 0; i > -1; i = i + x){ - analogWrite(PWMpin, i); - if (i = 255) x = -1; // switch direction at peak - delay(10); - } - } - - - -See also --------- - - -- `while <http://arduino.cc/en/Reference/While>`_ - diff --git a/docs/source/arduino/fpconstants.rst b/docs/source/arduino/fpconstants.rst deleted file mode 100644 index 284342b..0000000 --- a/docs/source/arduino/fpconstants.rst +++ /dev/null @@ -1,36 +0,0 @@ -.. _arduino-fpconstants: - -floating point constants -======================== - -Similar to integer constants, floating point constants are used to -make code more readable. Floating point constants are swapped at -compile time for the value to which the expression evaluates. - - - -Examples: - - - -``n = .005;`` - - - -Floating point constants can also be expressed in a variety of -scientific notation. 'E' and 'e' are both accepted as valid -exponent indicators. - - - -:: - - - floating-point evaluates to: also evaluates to: - constant - - 10.0 10 - 2.34E5 2.34 * 10^5 234000 - 67e-12 67.0 * 10^-12 .000000000067 - - diff --git a/docs/source/arduino/goto.rst b/docs/source/arduino/goto.rst deleted file mode 100644 index 1fcceb7..0000000 --- a/docs/source/arduino/goto.rst +++ /dev/null @@ -1,55 +0,0 @@ -.. _arduino-goto: - -goto -==== - -Transfers program flow to a labeled point in the program - - - -Syntax ------- - -label: - - - -goto label; // sends program flow to the label - - - -Tip ---- - -The use of *goto* is discouraged in C programming, and some authors -of C programming books claim that the *goto* statement is never -necessary, but used judiciously, it can simplify certain programs. -The reason that many programmers frown upon the use of *goto* is -that with the unrestrained use of *goto* statements, it is easy to -create a program with undefined program flow, which can never be -debugged. - - - -With that said, there are instances where a goto statement can come -in handy, and simplify coding. One of these situations is to break -out of deeply nested *for* loops, or *if* logic blocks, on a -certain condition. - - - -Example -------- - -:: - - for(byte r = 0; r < 255; r++){ - for(byte g = 255; g > -1; g--){ - for(byte b = 0; b < 255; b++){ - if (analogRead(0) > 250){ goto bailout;} - // more statements ... - } - } - } - bailout: - diff --git a/docs/source/arduino/highbyte.rst b/docs/source/arduino/highbyte.rst deleted file mode 100644 index dc6a1d6..0000000 --- a/docs/source/arduino/highbyte.rst +++ /dev/null @@ -1,42 +0,0 @@ -.. _arduino-highbyte: - -highByte() -========== - -Description ------------ - -Extracts the high-order (leftmost) byte of a word (or the second -lowest byte of a larger data type). - - - -Syntax ------- - -highByte(x) - - - -Parameters ----------- - -x: a value of any type - - - -Returns -------- - -byte - - - -See also --------- - - -- `lowByte <http://arduino.cc/en/Reference/LowByte>`_\ () -- `word <http://arduino.cc/en/Reference/WordCast>`_\ () - - diff --git a/docs/source/arduino/if.rst b/docs/source/arduino/if.rst deleted file mode 100644 index d75f6d3..0000000 --- a/docs/source/arduino/if.rst +++ /dev/null @@ -1,95 +0,0 @@ -.. _arduino-if: - -if (conditional) and ==, !=, <, > (comparison operators) -======================================================== - -**``if``**, which is used in conjunction with a comparison -operator, tests whether a certain condition has been reached, such -as an input being above a certain number. The format for an if test -is: - - - -:: - - if (someVariable > 50) - { - // do something here - } - - - -The program tests to see if someVariable is greater than 50. If it -is, the program takes a particular action. Put another way, if the -statement in parentheses is true, the statements inside the -brackets are run. If not, the program skips over the code. - - - -The brackets may be omitted after an *if* statement. If this is -done, the next line (defined by the semicolon) becomes the only -conditional statement. - -:: - - - if (x > 120) digitalWrite(LEDpin, HIGH); - - if (x > 120) - digitalWrite(LEDpin, HIGH); - - if (x > 120){ digitalWrite(LEDpin, HIGH); } - - if (x > 120){ - digitalWrite(LEDpin1, HIGH); - digitalWrite(LEDpin2, HIGH); - } // all are correct - - - -The statements being evaluated inside the parentheses require the -use of one or more operators: - - - -Comparison Operators: -~~~~~~~~~~~~~~~~~~~~~ - -:: - - x == y (x is equal to y) - x != y (x is not equal to y) - x < y (x is less than y) - x > y (x is greater than y) - x <= y (x is less than or equal to y) - x >= y (x is greater than or equal to y) - - - -Warning: --------- - -Beware of accidentally using the single equal sign -(e.g.``if (x = 10)`` ). The single equal sign is the assignment -operator, and sets x to 10 (puts the value 10 into the variable x). -Instead use the double equal sign (e.g.``if (x == 10)``), which is -the comparison operator, and tests *whether* x is equal to 10 or -not. The latter statement is only true if x equals 10, but the -former statement will always be true. - - - -This is because C evaluates the statement ``if (x=10)`` as follows: -10 is assigned to x (remember that the single equal sign is the -`assignment operator <http://arduino.cc/en/Reference/Assignment>`_), -so x now contains 10. Then the 'if' conditional evaluates 10, which -always evaluates to TRUE, since any non-zero number evaluates to -TRUE. Consequently, ``if (x = 10)`` will always evaluate to TRUE, -which is not the desired result when using an 'if' statement. -Additionally, the variable x will be set to 10, which is also not a -desired action. - - - -**if** can also be part of a branching control structure using the -`if...else <http://arduino.cc/en/Reference/Else>`_] construction. diff --git a/docs/source/arduino/include.rst b/docs/source/arduino/include.rst deleted file mode 100644 index 6d53801..0000000 --- a/docs/source/arduino/include.rst +++ /dev/null @@ -1,42 +0,0 @@ -.. _arduino-include: - -#include -======== - -**#include** is used to include outside libraries in your sketch. -This gives the programmer access to a large group of standard C -libraries (groups of pre-made functions), and also libraries -written especially for Arduino. - - - -The main reference page for AVR C libraries (AVR is a reference to -the Atmel chips on which the Arduino is based) is -`here. <http://www.nongnu.org/avr-libc/user-manual/modules.html>`_ - - - -Note that **#include**, similar to **#define**, has no semicolon -terminator, and the compiler will yield cryptic error messages if -you add one. - - - -Example -------- - -This example includes a library that is used to put data into the -program space *flash* instead of *ram*. This saves the ram space -for dynamic memory needs and makes large lookup tables more -practical. - - - -:: - - #include <avr/pgmspace.h> - - prog_uint16_t myConstants[] PROGMEM = {0, 21140, 702 , 9128, 0, 25764, 8456, - 0,0,0,0,0,0,0,0,29810,8968,29762,29762,4500}; - - diff --git a/docs/source/arduino/increment.rst b/docs/source/arduino/increment.rst deleted file mode 100644 index f9e87c9..0000000 --- a/docs/source/arduino/increment.rst +++ /dev/null @@ -1,58 +0,0 @@ -.. _arduino-increment: - -++ (increment) / -- (decrement) -=============================== - -Description ------------ - -Increment or decrement a variable - - - -Syntax ------- - -:: - - x++; // increment x by one and returns the old value of x - ++x; // increment x by one and returns the new value of x - - x-- ; // decrement x by one and returns the old value of x - --x ; // decrement x by one and returns the new value of x - - - -Parameters ----------- - -x: an integer or long (possibly unsigned) - - - -Returns -------- - -The original or newly incremented / decremented value of the -variable. - - - -Examples --------- - -:: - - x = 2; - y = ++x; // x now contains 3, y contains 3 - y = x--; // x contains 2 again, y still contains 3 - - - -See also --------- - -`+= <http://arduino.cc/en/Reference/Arithmetic>`_ -`-= <http://arduino.cc/en/Reference/Arithmetic>`_ - - diff --git a/docs/source/arduino/incrementcompound.rst b/docs/source/arduino/incrementcompound.rst deleted file mode 100644 index 0005fbc..0000000 --- a/docs/source/arduino/incrementcompound.rst +++ /dev/null @@ -1,49 +0,0 @@ -.. _arduino-incrementcompound: - -+= , -= , \*= , /= -================== - -Description ------------ - -Perform a mathematical operation on a variable with another -constant or variable. The += (et al) operators are just a -convenient shorthand for the expanded syntax, listed below. - - - -Syntax ------- - -:: - - x += y; // equivalent to the expression x = x + y; - x -= y; // equivalent to the expression x = x - y; - x *= y; // equivalent to the expression x = x * y; - x /= y; // equivalent to the expression x = x / y; - - - -Parameters ----------- - -x: any variable type - - - -y: any variable type or constant - - - -Examples --------- - -:: - - x = 2; - x += 4; // x now contains 6 - x -= 3; // x now contains 3 - x *= 10; // x now contains 30 - x /= 2; // x now contains 15 - - diff --git a/docs/source/arduino/int.rst b/docs/source/arduino/int.rst deleted file mode 100644 index 2bb3bef..0000000 --- a/docs/source/arduino/int.rst +++ /dev/null @@ -1,84 +0,0 @@ -.. _arduino-int: - -int -=== - -Description ------------ - -Integers are your primary datatype for number storage, and store a -2 byte value. This yields a range of -32,768 to 32,767 (minimum -value of -2^15 and a maximum value of (2^15) - 1). - - - -Int's store negative numbers with a technique called -`2's complement math. <http://en.wikipedia.org/wiki/2's_complement>`_ -The highest bit, sometimes refered to as the "sign" bit, flags the -number as a negative number. The rest of the bits are inverted and -1 is added. - - - -The Arduino takes care of dealing with negative numbers for you, so -that arithmetic operations work transparently in the expected -manner. There can be an unexpected complication in dealing with the -`bitshift right operator (>>) <http://arduino.cc/en/Reference/Bitshift>`_ -however. - - - -Example -------- - -:: - - int ledPin = 13; - - - -Syntax ------- - -:: - - int var = val; - - - - -- var - your int variable name -- val - the value you assign to that variable - - - -Coding Tip ----------- - -When variables are made to exceed their maximum capacity they "roll -over" back to their minimum capacitiy, note that this happens in -both directions. - - - -:: - - int x - x = -32,768; - x = x - 1; // x now contains 32,767 - rolls over in neg. direction - - x = 32,767; - x = x + 1; // x now contains -32,768 - rolls over - - - -See Also --------- - - -- `byte <http://arduino.cc/en/Reference/Byte>`_ -- `unsigned int <http://arduino.cc/en/Reference/UnsignedInt>`_ -- `long <http://arduino.cc/en/Reference/Long>`_ -- `unsigned long <http://arduino.cc/en/Reference/UnsignedLong>`_ -- `Integer Constants <http://arduino.cc/en/Reference/IntegerConstants>`_ -- `Variable Declaration <http://arduino.cc/en/Reference/VariableDeclaration>`_ diff --git a/docs/source/arduino/intcast.rst b/docs/source/arduino/intcast.rst deleted file mode 100644 index d6bcca4..0000000 --- a/docs/source/arduino/intcast.rst +++ /dev/null @@ -1,41 +0,0 @@ -.. _arduino-intcast: - -int() -===== - -Description ------------ - -Converts a value to the `int <http://arduino.cc/en/Reference/Int>`_ -data type. - - - -Syntax ------- - -int(x) - - - -Parameters ----------- - -x: a value of any type - - - -Returns -------- - -int - - - -See also --------- - - -- `int <http://arduino.cc/en/Reference/Int>`_ - - diff --git a/docs/source/arduino/integerconstants.rst b/docs/source/arduino/integerconstants.rst deleted file mode 100644 index d60ed24..0000000 --- a/docs/source/arduino/integerconstants.rst +++ /dev/null @@ -1,130 +0,0 @@ -.. _arduino-integerconstants: - -Integer Constants -================= - -Integer constants are numbers used directly in a sketch, like -``123``. By default, these numbers are treated as -`int <http://arduino.cc/en/Reference/Int>`_'s but you can change -this with the U and L modifiers (see below). - - - -Normally, integer constants are treated as base 10 (decimal) -integers, but special notation (formatters) may be used to enter -numbers in other bases. - - - -:: - - Base Example Formatter Comment - - 10 (decimal) 123 none - - 2 (binary) B1111011 leading 'B' only works with 8 bit values (0 to 255) - characters 0-1 valid - - 8 (octal) 0173 leading "0" characters 0-7 valid - - 16 (hexadecimal) 0x7B leading "0x" characters 0-9, A-F, a-f valid - - - -**Decimal** is base 10. This is the common-sense math with which -you are acquainted. Constants without other prefixes are assumed to -be in decimal format. - - - -Example: -:: - - 101 // same as 101 decimal ((1 * 10^2) + (0 * 10^1) + 1) - -**Binary** is base two. Only characters 0 and 1 are valid. - - - -Example: -:: - - B101 // same as 5 decimal ((1 * 2^2) + (0 * 2^1) + 1) - -The binary formatter only works on bytes (8 bits) between 0 (B0) -and 255 (B11111111). If it is convenient to input an int (16 bits) -in binary form you can do it a two-step procedure such as: - - - -:: - - myInt = (B11001100 * 256) + B10101010; // B11001100 is the high byte - - - -**Octal** is base eight. Only characters 0 through 7 are valid. -Octal values are indicated by the prefix "0" - - - -Example: - -:: - - 0101 // same as 65 decimal ((1 * 8^2) + (0 * 8^1) + 1) - -Warning -It is possible to generate a hard-to-find bug by (unintentionally) -including a leading zero before a constant and having the compiler -unintentionally interpret your constant as octal. -**Hexadecimal (or hex)** is base sixteen. Valid characters are 0 -through 9 and letters A through F; A has the value 10, B is 11, up -to F, which is 15. Hex values are indicated by the prefix "0x". -Note that A-F may be syted in upper or lower case (a-f). - - - -Example: - -:: - - 0x101 // same as 257 decimal ((1 * 16^2) + (0 * 16^1) + 1) - - - -U & L formatters ----------------- - -By default, an integer constant is treated as an -`int <http://arduino.cc/en/Reference/Int>`_ with the attendant -limitations in values. To specify an integer constant with another -data type, follow it with: - - - - -- a 'u' or 'U' to force the constant into an unsigned data format. - Example: ``33u`` -- a 'l' or 'L' to force the constant into a long data format. - Example: ``100000L`` -- a 'ul' or 'UL' to force the constant into an unsigned long - constant. Example: ``32767ul`` - - - - - -See also --------- - - -- `constants <http://arduino.cc/en/Reference/Constants>`_ -- `#define <http://arduino.cc/en/Reference/Define>`_ -- `byte <http://arduino.cc/en/Reference/Byte>`_ -- `int <http://arduino.cc/en/Reference/Int>`_ -- `unsigned int <http://arduino.cc/en/Reference/UnsignedInt>`_ -- `long <http://arduino.cc/en/Reference/Long>`_ -- `unsigned long <http://arduino.cc/en/Reference/UnsignedLong>`_ - - diff --git a/docs/source/arduino/interrupts.rst b/docs/source/arduino/interrupts.rst deleted file mode 100644 index 282362b..0000000 --- a/docs/source/arduino/interrupts.rst +++ /dev/null @@ -1,59 +0,0 @@ -.. _arduino-interrupts: - -interrupts() -============ - -Description ------------ - -Re-enables interrupts (after they've been disabled by -`noInterrupts <http://arduino.cc/en/Reference/NoInterrupts>`_\ ()). -Interrupts allow certain important tasks to happen in the -background and are enabled by default. Some functions will not work -while interrupts are disabled, and incoming communication may be -ignored. Interrupts can slightly disrupt the timing of code, -however, and may be disabled for particularly critical sections of -code. - - - -Parameters ----------- - -None - - - -Returns -------- - -None - - - -Example -------- - -:: - - void setup() {} - - void loop() - { - noInterrupts(); - // critical, time-sensitive code here - interrupts(); - // other code here - } - - - -See Also --------- - - -- `noInterrupts <http://arduino.cc/en/Reference/NoInterrupts>`_\ () -- `attachInterrupt <http://arduino.cc/en/Reference/AttachInterrupt>`_\ () -- `detachInterrupt <http://arduino.cc/en/Reference/DetachInterrupt>`_\ () - - diff --git a/docs/source/arduino/long.rst b/docs/source/arduino/long.rst deleted file mode 100644 index 3d59896..0000000 --- a/docs/source/arduino/long.rst +++ /dev/null @@ -1,50 +0,0 @@ -.. _arduino-long: - -long -==== - -Description ------------ - -Long variables are extended size variables for number storage, and -store 32 bits (4 bytes), from -2,147,483,648 to 2,147,483,647. - - - -Example -------- - - - -:: - - long speedOfLight = 186000L; // see Integer Constants for explanation of the 'L' - - - -Syntax ------- - -:: - - long var = val; - - - - -- var - the long variable name -- val - the value assigned to the variable - - - -See Also --------- - - -- `byte <http://arduino.cc/en/Reference/Byte>`_ -- `int <http://arduino.cc/en/Reference/Int>`_ -- `unsigned int <http://arduino.cc/en/Reference/UnsignedInt>`_ -- `unsigned long <http://arduino.cc/en/Reference/UnsignedLong>`_ -- `Integer Constants <http://arduino.cc/en/Reference/IntegerConstants>`_ -- `Variable Declaration <http://arduino.cc/en/Reference/VariableDeclaration>`_ - diff --git a/docs/source/arduino/longcast.rst b/docs/source/arduino/longcast.rst deleted file mode 100644 index 9f31443..0000000 --- a/docs/source/arduino/longcast.rst +++ /dev/null @@ -1,41 +0,0 @@ -.. _arduino-longcast: - -long() -====== - -Description ------------ - -Converts a value to the -`long <http://arduino.cc/en/Reference/Long>`_ data type. - - - -Syntax ------- - -long(x) - - - -Parameters ----------- - -x: a value of any type - - - -Returns -------- - -long - - - -See also --------- - - -- `long <http://arduino.cc/en/Reference/Long>`_ - - diff --git a/docs/source/arduino/loop.rst b/docs/source/arduino/loop.rst deleted file mode 100644 index 165b7b0..0000000 --- a/docs/source/arduino/loop.rst +++ /dev/null @@ -1,39 +0,0 @@ -.. _arduino-loop: - -loop() -====== - -After creating a setup() function, which initializes and sets the -initial values, the loop() function does precisely what its name -suggests, and loops consecutively, allowing your program to change -and respond. Use it to actively control the Arduino board. - - - -Example -~~~~~~~ - -:: - - - int buttonPin = 3; - - // setup initializes serial and the button pin - void setup() - { - beginSerial(9600); - pinMode(buttonPin, INPUT); - } - - // loop checks the button pin each time, - // and will send serial if it is pressed - void loop() - { - if (digitalRead(buttonPin) == HIGH) - serialWrite('H'); - else - serialWrite('L'); - - delay(1000); - } - diff --git a/docs/source/arduino/lowbyte.rst b/docs/source/arduino/lowbyte.rst deleted file mode 100644 index d69f66a..0000000 --- a/docs/source/arduino/lowbyte.rst +++ /dev/null @@ -1,42 +0,0 @@ -.. _arduino-lowbyte: - -lowByte() -========= - -Description ------------ - -Extracts the low-order (rightmost) byte of a variable (e.g. a -word). - - - -Syntax ------- - -lowByte(x) - - - -Parameters ----------- - -x: a value of any type - - - -Returns -------- - -byte - - - -See also --------- - - -- `highByte <http://arduino.cc/en/Reference/HighByte>`_\ () -- `word <http://arduino.cc/en/Reference/WordCast>`_\ () - - diff --git a/docs/source/arduino/map.rst b/docs/source/arduino/map.rst deleted file mode 100644 index 65647fa..0000000 --- a/docs/source/arduino/map.rst +++ /dev/null @@ -1,119 +0,0 @@ -.. _arduino-map: - -map(value, fromLow, fromHigh, toLow, toHigh) -============================================ - -Description ------------ - -Re-maps a number from one range to another. That is, a **value** of -**fromLow** would get mapped to **toLow**, a value of **fromHigh** -to **toHigh**, values in-between to values in-between, etc. - - - -Does not constrain values to within the range, because out-of-range -values are sometimes intended and useful. The constrain() function -may be used either before or after this function, if limits to the -ranges are desired. - - - -Note that the "lower bounds" of either range may be larger or -smaller than the "upper bounds" so the map() function may be used -to reverse a range of numbers, for example - - - -``y = map(x, 1, 50, 50, 1);`` - - - -The function also handles negative numbers well, so that this -example - - - -``y = map(x, 1, 50, 50, -100);`` - - - -is also valid and works well. - - - -The map() function uses integer math so will not generate -fractions, when the math might indicate that it should do so. -Fractional remainders are truncated, and are not rounded or -averaged. - - - -Parameters ----------- - -value: the number to map - - - -fromLow: the lower bound of the value's current range - - - -fromHigh: the upper bound of the value's current range - - - -toLow: the lower bound of the value's target range - - - -toHigh: the upper bound of the value's target range - - - -Returns -------- - -The mapped value. - - - -Example -------- - -:: - - /* Map an analog value to 8 bits (0 to 255) */ - void setup() {} - - void loop() - { - int val = analogRead(0); - val = map(val, 0, 1023, 0, 255); - analogWrite(9, val); - } - - - -Appendix -~~~~~~~~ - -For the mathematically inclined, here's the whole function - - - -:: - - long map(long x, long in_min, long in_max, long out_min, long out_max) - { - return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min; - } - - - -See Also --------- - - -- `constrain <http://arduino.cc/en/Reference/Constrain>`_\ () diff --git a/docs/source/arduino/max.rst b/docs/source/arduino/max.rst deleted file mode 100644 index 375625c..0000000 --- a/docs/source/arduino/max.rst +++ /dev/null @@ -1,71 +0,0 @@ -.. _arduino-max: - -max(x, y) -========= - -Description ------------ - -Calculates the maximum of two numbers. - - - -Parameters ----------- - -x: the first number, any data type - - - -y: the second number, any data type - - - -Returns -------- - -The larger of the two parameter values. - - - -Example -------- - -:: - - sensVal = max(senVal, 20); // assigns sensVal to the larger of sensVal or 20 - // (effectively ensuring that it is at least 20) - -Note ----- - -Perhaps counter-intuitively, max() is often used to constrain the -lower end of a variable's range, while min() is used to constrain -the upper end of the range. - - - -Warning -------- - -Because of the way the max() function is implemented, avoid using -other functions inside the brackets, it may lead to incorrect -results - - - -:: - - max(a--, 0); // avoid this - yields incorrect results - - a--; // use this instead - - max(a, 0); // keep other math outside the function - - - -See also --------- - - -- `min <http://arduino.cc/en/Reference/Min>`_\ () -- `constrain <http://arduino.cc/en/Reference/Constrain>`_\ () diff --git a/docs/source/arduino/micros.rst b/docs/source/arduino/micros.rst deleted file mode 100644 index cdee497..0000000 --- a/docs/source/arduino/micros.rst +++ /dev/null @@ -1,66 +0,0 @@ -.. _arduino-micros: - -micros() -======== - -Description ------------ - -Returns the number of microseconds since the Arduino board began -running the current program. This number will overflow (go back to -zero), after approximately 70 minutes. On 16 MHz Arduino boards -(e.g. Duemilanove and Nano), this function has a resolution of four -microseconds (i.e. the value returned is always a multiple of -four). On 8 MHz Arduino boards (e.g. the LilyPad), this function -has a resolution of eight microseconds. - - - -*Note*: there are 1,000 microseconds in a millisecond and 1,000,000 -microseconds in a second. - - - -Parameters ----------- - -None - - - -Returns -------- - -Number of microseconds since the program started (*unsigned long*) - - - -Example -------- - -:: - - unsigned long time; - - void setup(){ - Serial.begin(9600); - } - void loop(){ - Serial.print("Time: "); - time = micros(); - //prints time since program started - Serial.println(time); - // wait a second so as not to send massive amounts of data - delay(1000); - } - - - -See also --------- - - -- `millis <http://arduino.cc/en/Reference/Millis>`_\ () -- `delay <http://arduino.cc/en/Reference/Delay>`_\ () -- `delayMicroseconds <http://arduino.cc/en/Reference/DelayMicroseconds>`_\ () - diff --git a/docs/source/arduino/millis.rst b/docs/source/arduino/millis.rst deleted file mode 100644 index 009517d..0000000 --- a/docs/source/arduino/millis.rst +++ /dev/null @@ -1,67 +0,0 @@ -.. _arduino-millis: - -millis() -======== - -Description ------------ - -Returns the number of milliseconds since the Arduino board began -running the current program. This number will overflow (go back to -zero), after approximately 50 days. - - - -Parameters ----------- - -None - - - -Returns -------- - -Number of milliseconds since the program started (*unsigned long*) - - - -Example -------- - -:: - - unsigned long time; - - void setup(){ - Serial.begin(9600); - } - void loop(){ - Serial.print("Time: "); - time = millis(); - //prints time since program started - Serial.println(time); - // wait a second so as not to send massive amounts of data - delay(1000); - } - - - -Tip: ----- - -Note that the parameter for millis is an unsigned long, errors may -be generated if a programmer tries to do math with other datatypes -such as ints. - - - -See also --------- - - -- `micros <http://arduino.cc/en/Reference/Micros>`_\ () -- `delay <http://arduino.cc/en/Reference/Delay>`_\ () -- `delayMicroseconds <http://arduino.cc/en/Reference/DelayMicroseconds>`_\ () -- `Tutorial: Blink Without Delay <http://arduino.cc/en/Tutorial/BlinkWithoutDelay>`_ - diff --git a/docs/source/arduino/min.rst b/docs/source/arduino/min.rst deleted file mode 100644 index fdd7a5f..0000000 --- a/docs/source/arduino/min.rst +++ /dev/null @@ -1,71 +0,0 @@ -.. _arduino-min: - -min(x, y) -========= - -Description ------------ - -Calculates the minimum of two numbers. - - - -Parameters ----------- - -x: the first number, any data type - - - -y: the second number, any data type - - - -Returns -------- - -The smaller of the two numbers. - - - -Examples --------- - -:: - - sensVal = min(sensVal, 100); // assigns sensVal to the smaller of sensVal or 100 - // ensuring that it never gets above 100. - -Note ----- - -Perhaps counter-intuitively, max() is often used to constrain the -lower end of a variable's range, while min() is used to constrain -the upper end of the range. - - - -Warning -------- - -Because of the way the min() function is implemented, avoid using -other functions inside the brackets, it may lead to incorrect -results - - - -:: - - min(a++, 100); // avoid this - yields incorrect results - - a++; - min(a, 100); // use this instead - keep other math outside the function - - - -See also --------- - - -- `max <http://arduino.cc/en/Reference/Max>`_\ () -- `constrain <http://arduino.cc/en/Reference/Constrain>`_\ () diff --git a/docs/source/arduino/modulo.rst b/docs/source/arduino/modulo.rst deleted file mode 100644 index 195d15b..0000000 --- a/docs/source/arduino/modulo.rst +++ /dev/null @@ -1,84 +0,0 @@ -.. _arduino-modulo: - -% (modulo) -========== - -Description ------------ - -Calculates the remainder when one integer is divided by another. It -is useful for keeping a variable within a particular range (e.g. -the size of an array). - - - -Syntax ------- - -result = dividend % divisor - - - -Parameters ----------- - -dividend: the number to be divided - - - -divisor: the number to divide by - - - -Returns -------- - -the remainder - - - -Examples --------- - -:: - - x = 7 % 5; // x now contains 2 - x = 9 % 5; // x now contains 4 - x = 5 % 5; // x now contains 0 - x = 4 % 5; // x now contains 4 - - - -Example Code ------------- - -:: - - /* update one value in an array each time through a loop */ - - int values[10]; - int i = 0; - - void setup() {} - - void loop() - { - values[i] = analogRead(0); - i = (i + 1) % 10; // modulo operator rolls over variable - } - - - -Tip ---- - -The modulo operator does not work on floats. - - - -See also --------- - - -- `division <http://arduino.cc/en/Reference/Arithmetic>`_ - diff --git a/docs/source/arduino/nointerrupts.rst b/docs/source/arduino/nointerrupts.rst deleted file mode 100644 index 10d504d..0000000 --- a/docs/source/arduino/nointerrupts.rst +++ /dev/null @@ -1,56 +0,0 @@ -.. _arduino-nointerrupts: - -noInterrupts() -============== - -Description ------------ - -Disables interrupts (you can re-enable them with interrupts()). -Interrupts allow certain important tasks to happen in the -background and are enabled by default. Some functions will not work -while interrupts are disabled, and incoming communication may be -ignored. Interrupts can slightly disrupt the timing of code, -however, and may be disabled for particularly critical sections of -code. - - - -Parameters ----------- - -None. - - - -Returns -------- - -None. - - - -Example -------- - -:: - - void setup() {} - - void loop() - { - noInterrupts(); - // critical, time-sensitive code here - interrupts(); - // other code here - } - - - -See Also --------- - - -- `interrupts <http://arduino.cc/en/Reference/Interrupts>`_\ () - - diff --git a/docs/source/arduino/pinmode.rst b/docs/source/arduino/pinmode.rst deleted file mode 100644 index 34c7998..0000000 --- a/docs/source/arduino/pinmode.rst +++ /dev/null @@ -1,67 +0,0 @@ -.. highlight:: cpp - -.. _arduino-pinmode: - -pinMode() -========= - -.. doxygenfunction:: pinMode - -.. doxygenenum:: WiringPinMode - -Discussion ----------- - -pinMode() is usually called within :ref:`arduino-setup` in order to -configure a pin for a certain usage (although it may be called from -anywhere). - - -Example -------- - - :: - - - int ledPin = 13; // LED connected to digital pin 13 - - void setup() - { - pinMode(ledPin, OUTPUT); // sets the digital pin as output - } - - void loop() - { - digitalWrite(ledPin, HIGH); // sets the LED on - delay(1000); // waits for a second - digitalWrite(ledPin, LOW); // sets the LED off - delay(1000); // waits for a second - } - - - -Arduino Compatibility Note --------------------------- - -The libmaple implementation of pinMode() supports OUTPUT and INPUT -modes with a meaning identical to that of the Arduino function. - -INPUT_ANALOG and PWM modes were added because the Maple does not -distinguish between analog and digital pins the same way the Arduino -does. Unlike the Arduino, you **must call pinMode**\ () to set up a pin -for these purposes before a call to, e.g., :ref:`arduino-analogRead`. -In practice, this should only add a few lines of pinMode() calls to -your :ref:`arduino-setup` function. - -OUTPUT_OPEN_DRAIN, INPUT_PULLUP, INPUT_PULLDOWN, and PWM_OPEN_DRAIN -modes represent functionality not currently available on Arduino -boards. - -See also --------- - -- :ref:`arduino-constants` -- :ref:`arduino-digitalwrite` -- :ref:`arduino-digitalread` -- Maple :ref:`GPIO <gpio>` reference page -- Arduino `pinMode() <http://www.arduino.cc/en/Reference/PinMode>`_ reference diff --git a/docs/source/arduino/pointer.rst b/docs/source/arduino/pointer.rst deleted file mode 100644 index 4e4b9e5..0000000 --- a/docs/source/arduino/pointer.rst +++ /dev/null @@ -1,16 +0,0 @@ -.. _arduino-pointer: - -The pointer operators -===================== - -& (reference) and \* (dereference) -================================== - -Pointers are one of the more complicated subjects for beginners in -learning C, and it is possible to write the vast majority of -Arduino sketches without ever encountering pointers. However for -manipulating certain data structures, the use of pointers can -simplify the code, and and knowledge of manipulating pointers is -handy to have in one's toolkit. - - diff --git a/docs/source/arduino/pow.rst b/docs/source/arduino/pow.rst deleted file mode 100644 index 3a09481..0000000 --- a/docs/source/arduino/pow.rst +++ /dev/null @@ -1,47 +0,0 @@ -.. _arduino-pow: - -pow(base, exponent) -=================== - -Description ------------ - -Calculates the value of a number raised to a power. Pow() can be -used to raise a number to a fractional power. This is useful for -generating exponential mapping of values or curves. - - - -Parameters ----------- - -base: the number (*float*) - - - -exponent: the power to which the base is raised (*float*) - - - -Returns -------- - -The result of the exponentiation (*double*) - - - -Example -------- - -See the `fscale <http://arduino.cc/playground/Main/Fscale>`_ -function in the code library. - - - -See also --------- - - -- `sqrt <http://arduino.cc/en/Reference/Sqrt>`_\ () -- `float <http://arduino.cc/en/Reference/Float>`_ -- `double <http://arduino.cc/en/Reference/Double>`_ diff --git a/docs/source/arduino/random.rst b/docs/source/arduino/random.rst deleted file mode 100644 index 44f122a..0000000 --- a/docs/source/arduino/random.rst +++ /dev/null @@ -1,92 +0,0 @@ -.. _arduino-random: - -random() -======== - -Description ------------ - -The random function generates pseudo-random numbers. - - - -Syntax ------- - -random(max) -random(min, max) - - - -Parameters ----------- - -min - lower bound of the random value, inclusive *(optional)* - - - -max - upper bound of the random value, exclusive - - - -Returns -------- - -a random number between min and max-1 (*long*) - - - -Note: ------ - -If it is important for a sequence of values generated by random() -to differ, on subsequent executions of a sketch, use randomSeed() -to initialize the random number generator with a fairly random -input, such as analogRead() on an unconnected pin. - - - -Conversely, it can occasionally be useful to use pseudo-random -sequences that repeat exactly. This can be accomplished by calling -randomSeed() with a fixed number, before starting the random -sequence. - - - -Example -------- - -:: - - long randNumber; - - void setup(){ - Serial.begin(9600); - - // if analog input pin 0 is unconnected, random analog - // noise will cause the call to randomSeed() to generate - // different seed numbers each time the sketch runs. - // randomSeed() will then shuffle the random function. - randomSeed(analogRead(0)); - } - - void loop() { - // print a random number from 0 to 299 - randNumber = random(300); - Serial.println(randNumber); - - // print a random number from 10 to 19 - randNumber = random(10, 20); - Serial.println(randNumber); - - delay(50); - } - - - -See also --------- - - -- `randomSeed <http://arduino.cc/en/Reference/RandomSeed>`_\ () - diff --git a/docs/source/arduino/randomseed.rst b/docs/source/arduino/randomseed.rst deleted file mode 100644 index b0b5d71..0000000 --- a/docs/source/arduino/randomseed.rst +++ /dev/null @@ -1,70 +0,0 @@ -.. _arduino-randomseed: - -randomSeed(seed) -================ - -Description ------------ - -randomSeed() initializes the pseudo-random number generator, -causing it to start at an arbitrary point in its random sequence. -This sequence, while very long, and random, is always the same. - - - -If it is important for a sequence of values generated by random() -to differ, on subsequent executions of a sketch, use randomSeed() -to initialize the random number generator with a fairly random -input, such as analogRead() on an unconnected pin. - - - -Conversely, it can occasionally be useful to use pseudo-random -sequences that repeat exactly. This can be accomplished by calling -randomSeed() with a fixed number, before starting the random -sequence. - - - -Parameters ----------- - -long, int - pass a number to generate the seed. - - - -Returns -------- - -no returns - - - -Example -------- - -:: - - long randNumber; - - void setup(){ - Serial.begin(9600); - randomSeed(analogRead(0)); - } - - void loop(){ - randNumber = random(300); - Serial.println(randNumber); - - delay(50); - } - - - -See also --------- - - -- `random <http://arduino.cc/en/Reference/Random>`_ - - diff --git a/docs/source/arduino/return.rst b/docs/source/arduino/return.rst deleted file mode 100644 index ae3b37d..0000000 --- a/docs/source/arduino/return.rst +++ /dev/null @@ -1,69 +0,0 @@ -.. _arduino-return: - -return -====== - -Terminate a function and return a value from a function to the -calling function, if desired. - - - -Syntax: -------- - -return; - - - -return value; // both forms are valid - - - -Parameters ----------- - -value: any variable or constant type - - - -Examples: ---------- - -A function to compare a sensor input to a threshold - -:: - - int checkSensor(){ - if (analogRead(0) > 400) { - return 1; - else{ - return 0; - } - } - - - -The return keyword is handy to test a section of code without -having to "comment out" large sections of possibly buggy code. - - - -:: - - void loop(){ - - // brilliant code idea to test here - - return; - - // the rest of a dysfunctional sketch here - // this code will never be executed - } - - - -See also --------- - -`comments <http://arduino.cc/en/Reference/Comments>`_ - diff --git a/docs/source/arduino/scope.rst b/docs/source/arduino/scope.rst deleted file mode 100644 index bb56246..0000000 --- a/docs/source/arduino/scope.rst +++ /dev/null @@ -1,56 +0,0 @@ -.. _arduino-scope: - -Variable Scope -============== - -Variables in the C programming language, which Arduino uses, have a -property called *scope*. This is in contrast to languages such as -BASIC where every variable is a *global* variable. - - - -A global variable is one that can be *seen* by every function in a -program. Local variables are only visible to the function in which -they are declared. In the Arduino environment, any variable -declared outside of a function (e.g. setup(), loop(), etc. ), is a -global variable. - - - -When programs start to get larger and more complex, local variables -are a useful way to insure that only one function has access to its -own variables. This prevents programming errors when one function -inadvertently modifies variables used by another function. - - - -It is also sometimes handy to declare and initialize a variable -inside a *for* loop. This creates a variable that can only be -accessed from inside the for-loop brackets. - - - -Example: --------- - -:: - - int gPWMval; // any function will see this variable - - void setup() - { - // ... - } - - void loop() - { - int i; // "i" is only "visible" inside of "loop" - float f; // "f" is only "visible" inside of "loop" - // ... - - for (int j = 0; j <100; j++){ - // variable j can only be accessed inside the for-loop brackets - } - - } - diff --git a/docs/source/arduino/serial.rst b/docs/source/arduino/serial.rst deleted file mode 100644 index 31ce06c..0000000 --- a/docs/source/arduino/serial.rst +++ /dev/null @@ -1,62 +0,0 @@ -.. _arduino-serial: - -Serial -====== - -Used for communication between the Arduino board and a computer or -other devices. All Arduino boards have at least one serial port -(also known as a UART or USART): **Serial**. It communicates on -digital pins 0 (RX) and 1 (TX) as well as with the computer via -USB. Thus, if you use these functions, you cannot also use pins 0 -and 1 for digital input or output. - - - -You can use the Arduino environment's built-in serial monitor to -communicate with an Arduino board. Click the serial monitor button -in the toolbar and select the same baud rate used in the call to -begin(). - - - -The Arduino Mega has three additional serial ports: **Serial1** on -pins 19 (RX) and 18 (TX), **Serial2** on pins 17 (RX) and 16 (TX), -**Serial3** on pins 15 (RX) and 14 (TX). To use these pins to -communicate with your personal computer, you will need an -additional USB-to-serial adaptor, as they are not connected to the -Mega's USB-to-serial adaptor. To use them to communicate with an -external TTL serial device, connect the TX pin to your device's RX -pin, the RX to your device's TX pin, and the ground of your Mega to -your device's ground. (Don't connect these pins directly to an -RS232 serial port; they operate at +/- 12V and can damage your -Arduino board.) - - - -Functions ---------- - - -- `begin <http://arduino.cc/en/Serial/Begin>`_\ () -- `end <http://arduino.cc/en/Serial/End>`_\ () -- `available <http://arduino.cc/en/Serial/Available>`_\ () -- `read <http://arduino.cc/en/Serial/Read>`_\ () -- `flush <http://arduino.cc/en/Serial/Flush>`_\ () -- `print <http://arduino.cc/en/Serial/Print>`_\ () -- `println <http://arduino.cc/en/Serial/Println>`_\ () -- `write <http://arduino.cc/en/Serial/Write>`_\ () - - - -Examples --------- - - -- `ASCII Table <http://arduino.cc/en/Tutorial/ASCIITable>`_ -- `Dimmer <http://arduino.cc/en/Tutorial/Dimmer>`_ -- `Graph <http://arduino.cc/en/Tutorial/Graph>`_ -- `Physical Pixel <http://arduino.cc/en/Tutorial/PhysicalPixel>`_ -- `Virtual Color Mixer <http://arduino.cc/en/Tutorial/VirtualColorMixer>`_ -- `Serial Call Response <http://arduino.cc/en/Tutorial/SerialCallResponse>`_ -- `Serial Call Response ASCII <http://arduino.cc/en/Tutorial/SerialCallResponseASCII>`_ - diff --git a/docs/source/arduino/setup.rst b/docs/source/arduino/setup.rst deleted file mode 100644 index 05911ed..0000000 --- a/docs/source/arduino/setup.rst +++ /dev/null @@ -1,31 +0,0 @@ -.. _arduino-setup: - -setup() -======= - -The setup() function is called when a sketch starts. Use it to -initialize variables, pin modes, start using libraries, etc. The -setup function will only run once, after each powerup or reset of -the Arduino board. - - - -Example -~~~~~~~ - -:: - - - int buttonPin = 3; - - void setup() - { - Serial.begin(9600); - pinMode(buttonPin, INPUT); - } - - void loop() - { - // ... - } - diff --git a/docs/source/arduino/sin.rst b/docs/source/arduino/sin.rst deleted file mode 100644 index 3a06a8f..0000000 --- a/docs/source/arduino/sin.rst +++ /dev/null @@ -1,35 +0,0 @@ -.. _arduino-sin: - -sin(rad) -======== - -Description ------------ - -Calculates the sine of an angle (in radians). The result will be -between -1 and 1. - - - -Parameters ----------- - -rad: the angle in radians (*float*) - - - -Returns -------- - -the sine of the angle (*double*) - - - -See also --------- - - -- `cos <http://arduino.cc/en/Reference/Cos>`_\ () -- `tan <http://arduino.cc/en/Reference/Tan>`_\ () -- `float <http://arduino.cc/en/Reference/Float>`_ -- `double <http://arduino.cc/en/Reference/Double>`_ diff --git a/docs/source/arduino/sizeof.rst b/docs/source/arduino/sizeof.rst deleted file mode 100644 index a95dfbf..0000000 --- a/docs/source/arduino/sizeof.rst +++ /dev/null @@ -1,71 +0,0 @@ -.. _arduino-sizeof: - -sizeof -====== - -Description ------------ - -The sizeof operator returns the number of bytes in a variable type, -or the number of bytes occupied by an array. - - - -Syntax ------- - -sizeof(variable) - - - -Parameters ----------- - -variable: any variable type or array (e.g. int, float, byte) - - - -Example code ------------- - -The sizeof operator is useful for dealing with arrays (such as -strings) where it is convenient to be able to change the size of -the array without breaking other parts of the program. - - - -This program prints out a text string one character at a time. Try -changing the text phrase. - - - -:: - - char myStr[] = "this is a test"; - int i; - - void setup(){ - Serial.begin(9600); - } - - void loop() { - for (i = 0; i < sizeof(myStr) - 1; i++){ - Serial.print(i, DEC); - Serial.print(" = "); - Serial.println(myStr[i], BYTE); - } - } - - -Note that sizeof returns the total number of bytes. So for larger -variable types such as ints, the for loop would look something like -this. - - - -:: - - for (i = 0; i < (sizeof(myInts)/sizeof(int)) - 1; i++) { - // do something with myInts[i] - } - diff --git a/docs/source/arduino/sqrt.rst b/docs/source/arduino/sqrt.rst deleted file mode 100644 index 5b8a73e..0000000 --- a/docs/source/arduino/sqrt.rst +++ /dev/null @@ -1,33 +0,0 @@ -.. _arduino-sqrt: - -sqrt(x) -======= - -Description ------------ - -Calculates the square root of a number. - - - -Parameters ----------- - -x: the number, any data type - - - -Returns -------- - -double, the number's square root. - - - -See also --------- - - -- `pow <http://arduino.cc/en/Reference/Pow>`_\ () -- `sq <http://arduino.cc/en/Reference/Sq>`_\ () - diff --git a/docs/source/arduino/static.rst b/docs/source/arduino/static.rst deleted file mode 100644 index 1c0340e..0000000 --- a/docs/source/arduino/static.rst +++ /dev/null @@ -1,71 +0,0 @@ -.. _arduino-static: - -Static -====== - -The static keyword is used to create variables that are visible to -only one function. However unlike local variables that get created -and destroyed every time a function is called, static variables -persist beyond the function call, preserving their data between -function calls. - - - -Variables declared as static will only be created and initialized -the first time a function is called. - - - -Example -------- - -:: - - - - /* RandomWalk - * Paul Badger 2007 - * RandomWalk wanders up and down randomly between two - * endpoints. The maximum move in one loop is governed by - * the parameter "stepsize". - * A static variable is moved up and down a random amount. - * This technique is also known as "pink noise" and "drunken walk". - */ - - #define randomWalkLowRange -20 - #define randomWalkHighRange 20 - int stepsize; - - int thisTime; - int total; - - void setup() - { - Serial.begin(9600); - } - - void loop() - { // tetst randomWalk function - stepsize = 5; - thisTime = randomWalk(stepsize); - Serial.println(thisTime); - delay(10); - } - - int randomWalk(int moveSize){ - static int place; // variable to store value in random walk - declared static so that it stores - // values in between function calls, but no other functions can change its value - - place = place + (random(-moveSize, moveSize + 1)); - - if (place < randomWalkLowRange){ // check lower and upper limits - place = place + (randomWalkLowRange - place); // reflect number back in positive direction - } - else if(place > randomWalkHighRange){ - place = place - (place - randomWalkHighRange); // reflect number back in negative direction - } - - return place; - } - - diff --git a/docs/source/arduino/string.rst b/docs/source/arduino/string.rst deleted file mode 100644 index b841728..0000000 --- a/docs/source/arduino/string.rst +++ /dev/null @@ -1,158 +0,0 @@ -.. _arduino-string: - -string -====== - -Description ------------ - -Text strings can be represented in two ways. you can use the String -data type, which is part of the core as of version 0019, or you can -make a string out of an array of type char and null-terminate it. -This page described the latter method. For more details on the -String object, which gives you more functionality at the cost of -more memory, see the -`String object <http://arduino.cc/en/Reference/StringObject>`_ -page. - - - -Examples --------- - -All of the following are valid declarations for strings. - -:: - - char Str1[15]; - char Str2[8] = {'a', 'r', 'd', 'u', 'i', 'n', 'o'}; - char Str3[8] = {'a', 'r', 'd', 'u', 'i', 'n', 'o', '\0'}; - char Str4[ ] = "arduino"; - char Str5[8] = "arduino"; - char Str6[15] = "arduino"; - - - -**Possibilities for declaring strings** - - - - -- Declare an array of chars without initializing it as in Str1 -- Declare an array of chars (with one extra char) and the compiler - will add the required null character, as in Str2 -- Explicitly add the null character, Str3 -- Initialize with a string constant in quotation marks; the - compiler will size the array to fit the string constant and a - terminating null character, Str4 -- Initialize the array with an explicit size and string constant, - Str5 -- Initialize the array, leaving extra space for a larger string, - Str6 - - - -**Null termination** - - - -Generally, strings are terminated with a null character (ASCII code -0). This allows functions (like Serial.print()) to tell where the -end of a string is. Otherwise, they would continue reading -subsequent bytes of memory that aren't actually part of the -string. - - - -This means that your string needs to have space for one more -character than the text you want it to contain. That is why Str2 -and Str5 need to be eight characters, even though "arduino" is only -seven - the last position is automatically filled with a null -character. Str4 will be automatically sized to eight characters, -one for the extra null. In Str3, we've explicitly included the null -character (written '\\0') ourselves. - - - -Note that it's possible to have a string without a final null -character (e.g. if you had specified the length of Str2 as seven -instead of eight). This will break most functions that use strings, -so you shouldn't do it intentionally. If you notice something -behaving strangely (operating on characters not in the string), -however, this could be the problem. - - - -**Single quotes or double quotes?** - - - -Strings are always defined inside double quotes ("Abc") and -characters are always defined inside single quotes('A'). - - - -**Wrapping long strings** - - - -You can wrap long strings like this: - -:: - - char myString[] = "This is the first line" - " this is the second line" - " etcetera"; - - - -**Arrays of strings** - - - -It is often convenient, when working with large amounts of text, -such as a project with an LCD display, to setup an array of -strings. Because strings themselves are arrays, this is in actually -an example of a two-dimensional array. - - - -In the code below, the asterisk after the datatype char "char\*" -indicates that this is an array of "pointers". All array names are -actually pointers, so this is required to make an array of arrays. -Pointers are one of the more esoteric parts of C for beginners to -understand, but it isn't necessary to understand pointers in detail -to use them effectively here. - - - -Example -------- - -:: - - - char* myStrings[]={"This is string 1", "This is string 2", "This is string 3", - "This is string 4", "This is string 5","This is string 6"}; - - void setup(){ - Serial.begin(9600); - } - - void loop(){ - for (int i = 0; i < 6; i++){ - Serial.println(myStrings[i]); - delay(500); - } - } - - - -See Also --------- - - -- `array <http://arduino.cc/en/Reference/Array>`_ -- `PROGMEM <http://arduino.cc/en/Reference/PROGMEM>`_ -- `Variable Declaration <http://arduino.cc/en/Reference/VariableDeclaration>`_ - diff --git a/docs/source/arduino/switchcase.rst b/docs/source/arduino/switchcase.rst deleted file mode 100644 index 28791eb..0000000 --- a/docs/source/arduino/switchcase.rst +++ /dev/null @@ -1,77 +0,0 @@ -.. _arduino-switchcase: - -switch / case statements -======================== - -Like **if** statements, **switch...case** controls the flow of -programs by allowing programmers to specify different code that -should be executed in various conditions. In particular, a switch -statement compares the value of a variable to the values specified -in case statements. When a case statement is found whose value -matches that of the variable, the code in that case statement is -run. - - - -The **break** keyword exits the switch statement, and is typically -used at the end of each case. Without a break statement, the switch -statement will continue executing the following expressions -("falling-through") until a break, or the end of the switch -statement is reached. - - - -Example -~~~~~~~ - -:: - - switch (var) { - case 1: - //do something when var equals 1 - break; - case 2: - //do something when var equals 2 - break; - default: - // if nothing else matches, do the default - // default is optional - } - - - -Syntax -~~~~~~ - -:: - - switch (var) { - case label: - // statements - break; - case label: - // statements - break; - default: - // statements - } - - - -Parameters -~~~~~~~~~~ - -var: the variable whose value to compare to the various cases - - - -label: a value to compare the variable to - - - -See also: ---------- - -`if...else <http://arduino.cc/en/Reference/Else>`_ - - diff --git a/docs/source/arduino/tan.rst b/docs/source/arduino/tan.rst deleted file mode 100644 index f31b357..0000000 --- a/docs/source/arduino/tan.rst +++ /dev/null @@ -1,35 +0,0 @@ -.. _arduino-tan: - -tan(rad) -======== - -Description ------------ - -Calculates the tangent of an angle (in radians). The result will be -between negative infinity and infinity. - - - -Parameters ----------- - -rad: the angle in radians (*float*) - - - -Returns -------- - -The tangent of the angle (*double*) - - - -See also --------- - - -- `sin <http://arduino.cc/en/Reference/Sin>`_\ () -- `cos <http://arduino.cc/en/Reference/Cos>`_\ () -- `float <http://arduino.cc/en/Reference/Float>`_ -- `double <http://arduino.cc/en/Reference/Double>`_ diff --git a/docs/source/arduino/unsignedchar.rst b/docs/source/arduino/unsignedchar.rst deleted file mode 100644 index f846105..0000000 --- a/docs/source/arduino/unsignedchar.rst +++ /dev/null @@ -1,41 +0,0 @@ -.. _arduino-unsignedchar: - -unsigned char -============= - -Description ------------ - -An unsigned data type that occupies 1 byte of memory. Same as the -`byte <http://arduino.cc/en/Reference/Byte>`_ datatype. - - - -The unsigned char datatype encodes numbers from 0 to 255. - - - -For consistency of Arduino programming style, the *byte* data type -is to be preferred. - - - -Example -------- - -:: - - unsigned char myChar = 240; - - - -See also --------- - - -- `byte <http://arduino.cc/en/Reference/Byte>`_ -- `int <http://arduino.cc/en/Reference/Int>`_ -- `array <http://arduino.cc/en/Reference/Array>`_ -- `Serial.println <http://arduino.cc/en/Serial/Println>`_ - - diff --git a/docs/source/arduino/unsignedint.rst b/docs/source/arduino/unsignedint.rst deleted file mode 100644 index 10835fe..0000000 --- a/docs/source/arduino/unsignedint.rst +++ /dev/null @@ -1,77 +0,0 @@ -.. _arduino-unsignedint: - -unsigned int -============ - -Description ------------ - -Unsigned ints (unsigned integers) are the same as ints in that they -store a 2 byte value. Instead of storing negative numbers however -they only store positive values, yielding a useful range of 0 to -65,535 (2^16) - 1). - - - -The difference between unsigned ints and (signed) ints, lies in the -way the highest bit, sometimes refered to as the "sign" bit, is -interpreted. In the Arduino int type (which is signed), if the high -bit is a "1", the number is interpreted as a negative number, and -the other 15 bits are interpreted with -`2's complement math. <http://en.wikipedia.org/wiki/2's_complement>`_ - - - -Example -------- - -:: - - unsigned int ledPin = 13; - - - -Syntax ------- - -:: - - unsigned int var = val; - - - - -- var - your unsigned int variable name -- val - the value you assign to that variable - - - -Coding Tip ----------- - -When variables are made to exceed their maximum capacity they "roll -over" back to their minimum capacitiy, note that this happens in -both directions - - - -:: - - unsigned int x - x = 0; - x = x - 1; // x now contains 65535 - rolls over in neg direction - x = x + 1; // x now contains 0 - rolls over - - - -See Also --------- - - -- `byte <http://arduino.cc/en/Reference/Byte>`_ -- `int <http://arduino.cc/en/Reference/Int>`_ -- `long <http://arduino.cc/en/Reference/Long>`_ -- `unsigned long <http://arduino.cc/en/Reference/UnsignedLong>`_ -- `Variable Declaration <http://arduino.cc/en/Reference/VariableDeclaration>`_ - - diff --git a/docs/source/arduino/unsignedlong.rst b/docs/source/arduino/unsignedlong.rst deleted file mode 100644 index 1bdb434..0000000 --- a/docs/source/arduino/unsignedlong.rst +++ /dev/null @@ -1,63 +0,0 @@ -.. _arduino-unsignedlong: - -unsigned long -============= - -Description ------------ - -Unsigned long variables are extended size variables for number -storage, and store 32 bits (4 bytes). Unlike standard longs -unsigned longs won't store negative numbers, making their range -from 0 to 4,294,967,295 (2^32 - 1). - - - -Example -------- - -:: - - unsigned long time; - - void setup() - { - Serial.begin(9600); - } - - void loop() - { - Serial.print("Time: "); - time = millis(); - //prints time since program started - Serial.println(time); - // wait a second so as not to send massive amounts of data - delay(1000); - } - -Syntax ------- - -:: - - unsigned long var = val; - - - - -- var - your long variable name -- val - the value you assign to that variable - - - -See Also --------- - - -- `byte <http://arduino.cc/en/Reference/Byte>`_ -- `int <http://arduino.cc/en/Reference/Int>`_ -- `unsigned int <http://arduino.cc/en/Reference/UnsignedInt>`_ -- `long <http://arduino.cc/en/Reference/Long>`_ -- `Variable Declaration <http://arduino.cc/en/Reference/VariableDeclaration>`_ - - diff --git a/docs/source/arduino/void.rst b/docs/source/arduino/void.rst deleted file mode 100644 index 00166b6..0000000 --- a/docs/source/arduino/void.rst +++ /dev/null @@ -1,37 +0,0 @@ -.. _arduino-void: - -void -==== - -The void keyword is used only in function declarations. It -indicates that the function is expected to return no information to -the function from which it was called. - - - -Example: --------- - -:: - - // actions are performed in the functions "setup" and "loop" - // but no information is reported to the larger program - - void setup() - { - // ... - } - - void loop() - { - // ... - } - - - - -See also --------- - -`function declaration <http://arduino.cc/en/Reference/FunctionDeclaration>`_ - diff --git a/docs/source/arduino/volatile.rst b/docs/source/arduino/volatile.rst deleted file mode 100644 index 4212ac5..0000000 --- a/docs/source/arduino/volatile.rst +++ /dev/null @@ -1,70 +0,0 @@ -.. _arduino-volatile: - -volatile keyword -================ - -volatile is a keyword known as a variable *qualifier*, it is -usually used before the datatype of a variable, to modify the way -in which the compiler and subsequent program treats the variable. - - - -Declaring a variable volatile is a directive to the compiler. The -compiler is software which translates your C/C++ code into the -machine code, which are the real instructions for the Atmega chip -in the Arduino. - - - -Specifically, it directs the compiler to load the variable from RAM -and not from a storage register, which is a temporary memory -location where program variables are stored and manipulated. Under -certain conditions, the value for a variable stored in registers -can be inaccurate. - - - -A variable should be declared volatile whenever its value can be -changed by something beyond the control of the code section in -which it appears, such as a concurrently executing thread. In the -Arduino, the only place that this is likely to occur is in sections -of code associated with interrupts, called an interrupt service -routine. - - - -Example -------- - -:: - - // toggles LED when interrupt pin changes state - - int pin = 13; - volatile int state = LOW; - - void setup() - { - pinMode(pin, OUTPUT); - attachInterrupt(0, blink, CHANGE); - } - - void loop() - { - digitalWrite(pin, state); - } - - void blink() - { - state = !state; - } - - - -See also --------- - - -- `AttachInterrupt <http://arduino.cc/en/Reference/AttachInterrupt>`_ - - diff --git a/docs/source/arduino/while.rst b/docs/source/arduino/while.rst deleted file mode 100644 index 5155f09..0000000 --- a/docs/source/arduino/while.rst +++ /dev/null @@ -1,46 +0,0 @@ -.. _arduino-while: - -while loops -=========== - -Description ------------ - -**while** loops will loop continuously, and infinitely, until the -expression inside the parenthesis, () becomes false. Something must -change the tested variable, or the **while** loop will never exit. -This could be in your code, such as an incremented variable, or an -external condition, such as testing a sensor. - - - -Syntax ------- - -:: - - while(expression){ - // statement(s) - } - - - -Parameters ----------- - -expression - a (boolean) C statement that evaluates to true or -false - - - -Example -------- - -:: - - var = 0; - while(var < 200){ - // do something repetitive 200 times - var++; - } - diff --git a/docs/source/arduino/word.rst b/docs/source/arduino/word.rst deleted file mode 100644 index 39b3a0d..0000000 --- a/docs/source/arduino/word.rst +++ /dev/null @@ -1,29 +0,0 @@ -.. _arduino-word: - -word -==== - -Description ------------ - -A word stores a 16-bit unsigned number, from 0 to 65535. Same as an -unsigned int. - - - -Example -------- - -:: - - word w = 10000; - - - -See also --------- - - -- `byte <http://arduino.cc/en/Reference/Byte>`_ -- `word <http://arduino.cc/en/Reference/WordCast>`_\ () - diff --git a/docs/source/arduino/wordcast.rst b/docs/source/arduino/wordcast.rst deleted file mode 100644 index 5ef821c..0000000 --- a/docs/source/arduino/wordcast.rst +++ /dev/null @@ -1,51 +0,0 @@ -.. _arduino-wordcast: - -word() -====== - -Description ------------ - -Convert a value to the -`word <http://arduino.cc/en/Reference/Word>`_ data type or create a -word from two bytes. - - - -Syntax ------- - -word(x) -word(h, l) - - - -Parameters ----------- - -x: a value of any type - - - -h: the high-order (leftmost) byte of the word - - - -l: the low-order (rightmost) byte of the word - - - -Returns -------- - -word - - - -See also --------- - - -- `word <http://arduino.cc/en/Reference/Word>`_ - - diff --git a/docs/source/arm-gcc.rst b/docs/source/arm-gcc.rst index 21379db..ef745f5 100644 --- a/docs/source/arm-gcc.rst +++ b/docs/source/arm-gcc.rst @@ -1,13 +1,70 @@ .. _arm-gcc: -.. _arm-gcc-attribute-flash: -============ - GCC on ARM -============ +GCC for Maple +============= + +This document provides notes on the current usage of +``arm-none-eabi-gcc``, the `CodeSourcery <http://codesourcery.com>`_ +version of the GNU `GCC <http://gcc.gnu.org/>`_ compilers used to +compile programs for the Maple. It is not intended as a reference +manual for GCC; such manuals are available `elsewhere +<http://gcc.gnu.org/>`_. + +Obtaining ``arm-none-eabi-gcc`` +------------------------------- + +Recent versions of ``arm-none-eabi-gcc`` and associated tools are +included with the :ref:`Maple IDE <ide>`. + +Users who wish to use ``arm-none-eabi-gcc`` in concert with a standard +Unix toolchain are referred to our :ref:`unix-toolchain` reference, +which describes how to set up such an environment. + +LeafLabs mirrors some of the more recent versions of the compiler +under http://static.leaflabs.com/pub/codesourcery/\ , including +versions for OS X, win32, and 32-bit Linux. + +Compiler Flags Used by libmaple +------------------------------- + +This section documents the flags passed to ``arm-none-eabi-gcc`` by +the :ref:`Maple IDE <ide>` and the default Makefile provided with +:ref:`libmaple <unix-toolchain>`. The information in this section is +subject to change without notice. + +.. highlight:: sh + +The following flags are among those passed to the C compiler:: + + -Os -g -mcpu=cortex-m3 -mthumb -march=armv7-m -nostdlib + -ffunction-sections -fdata-sections -Wl,--gc-sections + +The following flags are among those passed to the C++ compiler:: + + -fno-rtti -fno-exceptions -Wall + +The following flags are among those passed to the assembler:: + + -mcpu=cortex-m3 -march=armv7-m -mthumb + +.. highlight:: cpp + +.. _arm-gcc-avr-gcc: + +Switching from AVR-GCC +---------------------- + +This section, which is expected to grow over time, describes +techniques for porting code which uses AVR-GCC features (AVR-GCC is +the compiler used by many Atmel AVR-based microcontroller boards, +including Arduino) for use on the Maple. + +.. _arm-gcc-attribute-flash: -Stub. +- Replacing ``PROGMEM``: You can direct the linker script provided + with libmaple to store a variable in flash by using + ``__attribute__((section (".USER_FLASH")))``, like so:: -Include special things, differences with AVR-GCC, using -``__attribute__`` to stick things in flash, etc. + uint32 arr[] __attribute__((section (".USER_FLASH"))) = {...}; diff --git a/docs/source/bootloader.rst b/docs/source/bootloader.rst index fea1f35..57833ed 100644 --- a/docs/source/bootloader.rst +++ b/docs/source/bootloader.rst @@ -1,8 +1,10 @@ .. highlight:: sh -================== - Maple Bootloader -================== +===================== + Maple Bootloader(s) +===================== + +.. TODO: add a section on flashing your own bootloader The firmware which allows the Maple to be reprogrammed via a USB connection. Every Maple board comes programmed with this by default, @@ -18,43 +20,46 @@ Flash memory and only runs when the chip is reset). .. contents:: Contents :local: -Bootloader Schemes Explained! ------------------------------ - -Maple Rev 3 (the version currently shipping) represents a drastic -remake of the core library as well as the upload process. Some of -these changes are aesthetic, refactoring and reorganization. Some are -performance minded. The changes to the bootloader, however, were -implemented to solve some really gritty cross platform issues. Before -delving in to how the Rev 1 bootloader worked and how the Rev 3 -bootloader works now, lets look at the features common to both of them -and touch a bit on the Arduino setup. This is a fairly involved -explanation, with a lot of details that are likely only interesting to -a few. If you just want to get the rough idea, skim this article. If -you want to start hacking on the bootloader, get in touch with us to -get even more info on how this all works. Of course, you can always -`check out the code at github <http://github.com/leaflabs/libmaple>`_! +Bootloader Schemes Explained +---------------------------- + +Maple Rev 3 and Rev 5 (Rev 5 is the version currently shipping) +represents a drastic remake of the core library as well as the upload +process. Thes changes to the bootloader, were implemented to resolve +platform-specific issues on Windows. Before delving into how the Rev +1 bootloader worked and how the Rev 5 bootloader works now, we'll +discuss the features common to each and touch a bit on the Arduino +setup. + +This is a fairly involved explanation, with a lot of details that are +likely only interesting to a few. If you just want to get the rough +idea, skim this article. If you want to start hacking on the +bootloader, get in touch with us to get even more info on how this all +works. And finally, you can always `check out the code at github +<http://github.com/leaflabs/libmaple>`_! Arduino ------- -Arduino is based off of AVR series micro controllers, most of which +Arduino is based off of AVR series microcontrollers, most of which lack USB support. Thus, boards like the Duemilanove add USB capability -via an FTDI USB to Serial converter chip. This chip interfaces with -the AVR over…serial. When you plug an Arduino into a computer, only an -FTDI driver is needed. Since the FTDI chip is separate from the AVR, -you can reset the Arduino without closing this USB connection with the -FTDI chip. To program an Arduino, the host machine sends a command -over the USB pipe (reset DTR) which in turn resets the AVR. The AVR -will boot into a bootloader, which waits for a second for any upload -commands over serial. The host machine can either send those commands, -or do nothing. In which case the AVR will quickly jump to user code +via an FTDI USB-to-Serial converter chip. This chip interfaces with +the AVR over an RS-232 serial interface. When you plug an Arduino into +a computer, only an FTDI driver is needed. Since the FTDI chip is +separate from the AVR, you can reset the Arduino without closing this +USB connection with the FTDI chip. + +To program an Arduino, the host machine sends a command over the USB +pipe (reset DTR) which in turn resets the AVR. The AVR will boot into +a bootloader, which waits for a second for any upload commands over +serial. The host machine can either send those commands, or do +nothing. If it does nothing, the AVR will quickly jump to user code and off you go. The whole process is quick, the bootloader doesn’t live for very long, and will exit almost immediately if no upload commands are received. -Maple Rev 1: The Horror... ---------------------------- +Maple Rev 1 +----------- Maple is based off the STM32 (ARM cortex M3) series chips, which do have embedded USB support. Thus, Maple doesn’t need the extra FTDI @@ -90,8 +95,8 @@ platforms to make everything work this way. .. _bootloader-rev3: -Maple Rev3 ----------- +Maple Rev3/Rev5 - DFU +--------------------- Maple Rev 3 takes a completely different tack, more along the lines of Arduino. In Rev 3, the device resets into bootloader mode, which @@ -132,3 +137,546 @@ alternate setting 0 or 1, respectively) and resets the board again. This time, however, no DFU transaction is initiated, and the bootloader gives way to user code, closing down the DFU pipe and bringing up the USB serial. + +.. .. _bootloader-rev6: + +.. Maple Rev6 - The Serial Bootloader (Tentative) +.. ---------------------------------------------- + +.. .. note:: This section documents an in-progress version of the Maple +.. bootloader. **No Maples yet sold use this bootloader protocol**. +.. It has not been yet been publicly released, and its interface is +.. not stable. + +.. The bootloader in Rev3/Rev5 works well on Linux, acceptably on Mac, +.. but was unsatisfactory on Windows. Unlike the other operating systems, +.. Windows needed to be manually pointed to both the driver to use for +.. programming (DFU, via `libusb <http://www.libusb.org/>`_) and the +.. driver to use for serial communication (usbser.sys, built in to +.. Windows). Since Maple operates in only one of these modes at a time, +.. driver installation was unnecessarily complicated. It was necessary to +.. bring Maple into the correct mode before installing each of the +.. drivers. Furthermore, because libusb is not bundled with Windows, and +.. its driver is not signed, Windows 7 users have been forced to +.. laboriously disable driver signing checks. Finally, Windows hates the +.. constant switching of the device between Serial and DFU modes (during +.. programming), and often prompts users to install drivers that are +.. already installed. We have therefore decided to abandon DFU. + +.. In our new bootloader scheme, Maple is simply a serial device. +.. Windows comes bundled with usbser.sys, so no driver signing is +.. required. The IDE installation process is greatly simplified, there +.. is no more switching back and forth between "modes", and we can build +.. in new functionality outside the DFU spec. + +.. The first incarnation of this serial-only bootloader leaves libmaple +.. and user code untouched. However, during programming, instead of +.. calling :command:`dfu-util` to upload code we will now call a newly +.. written utility script similar to `avr-dude +.. <http://savannah.nongnu.org/projects/avrdude/>`_. The high level +.. operation of the bootloader will remain the same - come on at startup, +.. wait for an upload operation or timeout, and jump to user code. + +.. The second version of this bootloader will eliminate this dependence +.. on resetting and timing out by having the bootloader run in the +.. background. It will additionally own the serial port. In this scheme, +.. sending data over the COM port while DTR is pulled low results in that +.. packet being captured by the bootloader and interpreted as a +.. bootloader command. When the user uploads a new program, the +.. bootloader will overwrite the old one, reset the various peripheral +.. registers, and jump to user code. All of this will occur without +.. resetting the chip and thus causing Maple to connect and disconnect +.. from your computer (which seems to cause many problems). + +.. The final version of this bootloader scheme will involve a separate +.. microcontroller, whose responsibilities are to drive the USB port, +.. program the main processor, and offer some amount of debugging +.. capability. This will allow user sketches to run on the bare metal of +.. the main processor, without any bootloader hiding underneath. This +.. approach is similar to the approaches taken by mbed and the Arduino +.. Uno. + +.. Regardless of which generation of the new serial bootloader you are +.. working with, the command interface is the same. The low level +.. communication protocol is inspired by STK-500, the protocol used to +.. program many AVR-based development boards. The protocol is a +.. packetized query-response scheme. The host PC initiates every +.. transaction, and for every query sent to the bootloader, a single +.. response will be returned (or the system times out). Data is +.. transmitted over 115.2kbps, 8 data bits, 1 stop bit, no parity +.. bit. Every query or response follows the same packet format that looks +.. like this: + +.. .. _bootloader-packet-structure: + +.. Packet Structure +.. ^^^^^^^^^^^^^^^^ + +.. A bootloader packet is composed of a sequence of fields, as follows. + +.. .. list-table:: +.. :header-rows: 1 + +.. * - Field +.. - Length (bytes) +.. - Value +.. - Description + +.. * - START +.. - 1 +.. - 0x1B +.. - Magic constant, indicates bootloader packet + +.. * - SEQUENCE_NUM +.. - 1 +.. - 0--0xFF +.. - Queries and responses must have the same sequence number; rolls +.. over to 0 after 0xFF + +.. * - MESSAGE_SIZE +.. - 2 +.. - 0--0xFFFF +.. - Size of message body, currently limited to a 1024B=1KB maximum + +.. * - TOKEN +.. - 1 +.. - 0x7F +.. - Differs from STK500 value of 0x0E + +.. * - MESSAGE_BODY +.. - Variable, determined by MESSAGE_SIZE field +.. - Command query or response +.. - See :ref:`next section <bootloader-commands>` + +.. * - CHECKSUM +.. - 4 +.. - XOR of all other 32-bit words in packet +.. - See :ref:`below <bootloader-checksum>` + +.. .. _bootloader-checksum: + +.. .. highlight:: cpp + +.. .. note:: When computing the checksum, the words in a packet are +.. interpreted big-endian (as if the packet were a sequence of 32-bit, +.. big-endian unsigned integers). If the end of the MESSAGE_BODY is +.. not aligned with a four-byte boundary, then the checksum will treat +.. it as if it was padded with zero bytes to a four-byte boundary. + +.. As a concrete example, an entire GET_INFO query (see :ref:`below +.. <bootloader-get-info>`), including the packet structure, is +.. comprised of the byte sequence :: + +.. {0x1B, 0x7F, 0x00, 0x01, 0x7F, 0x00, 0x64, 0x7F, 0x00, 0x01} + +.. The SEQUENCE_NUM of this query is 0x7F. + +.. .. highlight:: sh + +.. .. _bootloader-commands: + +.. Commands +.. ^^^^^^^^ + +.. The packet structure overhead is for reliability. The actual queries +.. and responses are transacted inside of the message body. Following +.. the STK-500 protocol, each query or response begins with the single +.. byte command field. For each query, the resultant response must begin +.. with the same CMD byte. For each type of command, the structure of +.. queries and responses is of fixed size. + +.. Also following STK-500, fields longer than 1 byte are transmitted MSB +.. first (big-endian). However, READ and WRITE commands operate byte-wise +.. (not word-wise); it is up to the host PC to ensure that alignment and +.. ordering issues are handled appropriately. + +.. .. _bootloader-get-info: + +.. GET_INFO +.. """""""" + +.. Used to query device characteristics. + +.. GET_INFO Query: + +.. .. list-table:: +.. :header-rows: 1 + +.. * - Field +.. - Bytes +.. - Comments + +.. * - GET_INFO +.. - 1 +.. - Value 0 + +.. GET_INFO Response: + +.. .. list-table:: +.. :header-rows: 1 +.. :widths: 4 2 10 + +.. * - Field +.. - Bytes +.. - Comments + +.. * - GET_INFO +.. - 1 +.. - Value 0 + +.. * - Endianness +.. - 1 +.. - 0 indicates little-endian, 1 indicates big-endian. +.. (Currently returns 0; this field allows for future +.. expansion). + +.. * - Available Ram +.. - 4 +.. - In bytes + +.. * - Available Flash +.. - 4 +.. - In bytes + +.. * - Flash Page Size +.. - 2 +.. - In bytes + +.. * - Starting Address (FLASH) +.. - 4 +.. - Usually 0x08005000 + +.. * - Starting Address (RAM) +.. - 4 +.. - Usually 0x200000C0 + +.. * - Bootloader Version +.. - 4 +.. - Current version 0x00060000 (MAJ,MIN) + +.. .. _bootloader-erase-page: + +.. ERASE_PAGE +.. """""""""" + +.. Used to erase flash pages. + +.. ERASE_PAGE query: + +.. .. list-table:: +.. :header-rows: 1 +.. :widths: 4 2 10 + +.. * - Field +.. - Bytes +.. - Comments + +.. * - ERASE_PAGE +.. - 1 +.. - Value 1 + +.. * - ADDRESS +.. - 4 +.. - Will erase whichever page contains ADDRESS + +.. ERASE_PAGE response: + +.. .. list-table:: +.. :header-rows: 1 +.. :widths: 3 2 10 + +.. * - Field +.. - Bytes +.. - Comments + +.. * - ERASE_PAGE +.. - 1 +.. - Value 1 + +.. * - SUCCESS +.. - 1 +.. - Either 0 (failure) or 1 (success) + +.. WRITE_BYTES +.. """"""""""" + +.. Used to write to RAM or flash. + +.. WRITE_BYTES query: + +.. .. list-table:: +.. :header-rows: 1 +.. :widths: 4 4 10 + +.. * - Field +.. - Bytes +.. - Comments + +.. * - WRITE_BYTES +.. - 1 +.. - Value 2 + +.. * - Starting Address +.. - 4 +.. - Can address arbitrary RAM, or :ref:`cleared +.. <bootloader-erase-page>` flash pages. + +.. * - DATA +.. - MESSAGE_SIZE - 5 +.. - See :ref:`Packet Structure <bootloader-packet-structure>` + +.. WRITE_BYTES response: + +.. .. list-table:: +.. :header-rows: 1 +.. :widths: 2 2 10 + +.. * - Field +.. - Bytes +.. - Comments + +.. * - WRITE_BYTES +.. - 1 +.. - Value 2 + +.. * - SUCCESS +.. - 1 +.. - Either 0 (failure) or 1 (success). Will fail if writes were +.. made to uncleared pages. Does not clean up failed writes +.. (memory will be left in an undefined state). + +.. READ_BYTES +.. """""""""" + +.. Used to read from RAM or flash. + +.. READ_BYTES query: + +.. .. list-table:: +.. :header-rows: 1 +.. :widths: 2 2 10 + +.. * - Field +.. - Bytes +.. - Comments + +.. * - READ_BYTES +.. - 1 +.. - Value 3 + +.. * - ADDRESS +.. - 4 +.. - Start of block to read. Must be a multiple of 4. + +.. * - LENGTH +.. - 2 +.. - Maximum number of bytes to read (currently, this may be at most +.. 1024 = 1KB). Must be a multiple of 4. + +.. READ_BYTES response: + +.. .. list-table:: +.. :header-rows: 1 +.. :widths: 2 2 10 + +.. * - Field +.. - Bytes +.. - Comments + +.. * - READ_BYTES +.. - 1 +.. - Value 3 + +.. * - DATA +.. - MESSAGE_SIZE - 1 +.. - Contains read bytes. The actual number of bytes read may be +.. less than the LENGTH field of the corresponding READ_BYTES +.. query. If this section is of length 0, this should be +.. interpreted as a read failure. See +.. :ref:`bootloader-packet-structure`. + +.. JUMP_TO_USER +.. """""""""""" + +.. Causes the bootloader to jump to user code's starting address. + +.. JUMP_TO_USER query: + +.. .. list-table:: +.. :header-rows: 1 +.. :widths: 2 1 10 + +.. * - Field +.. - Bytes +.. - Comments + +.. * - JUMP_TO_USER +.. - 1 +.. - Value 4 + +.. * - Location +.. - 1 +.. - 0 means jump to flash starting address, 1 means jump to RAM +.. starting address. See the :ref:`bootloader-get-info` command +.. for more information. + +.. JUMP_TO_USER response: + +.. .. list-table:: +.. :header-rows: 1 +.. :widths: 2 1 10 + +.. * - Field +.. - Bytes +.. - Comments + +.. * - JUMP_TO_USER +.. - 1 +.. - Value 4 + +.. * - SUCCESS +.. - 1 +.. - Either 0 (failure) or 1 (success). If successful, after the +.. response is sent, the bootloader ends this session and jumps to +.. the user code in flash or RAM as specified in the query's +.. Location field. + + +.. SOFT_RESET +.. """""""""" + +.. Engages a full software reset. + +.. SOFT_RESET query: + +.. .. list-table:: +.. :header-rows: 1 +.. :widths: 2 1 10 + +.. * - Field +.. - Bytes +.. - Comments + +.. * - SOFT_RESET +.. - 1 +.. - Value 5 + +.. SOFT_RESET response: + +.. .. list-table:: +.. :header-rows: 1 +.. :widths: 2 1 10 + +.. * - Field +.. - Bytes +.. - Comments + +.. * - SOFT_RESET +.. - 1 +.. - Value 5 + +.. * - SUCCESS +.. - 1 +.. - Either 0 or 1 (FAILED and OK, respectively). Will end this +.. bootloader session and reset the processor. + +.. _bootloader-reflashing: + +Flashing A Custom Bootloader +---------------------------- + +The STM32 microprocessor on the Maple comes with a built-in hardware +bootloader that can be used to flash a new (software) bootloader onto +the chip. This section describes how to go about this, using a Maple +Rev 3 or higher (if you have a Maple Rev 1; you don't have a BUT +button, and won't be able to follow these directions. A workaround is +detailed in `this forum posting +<http://forums.leaflabs.com/topic.php?id=32#post-126>`_). + +.. warning:: This section is directed at users wishing to write a + custom bootloader for the Maple, or update their bootloader to a + more recent version. It's generally not necessary to do so, and it + is possible to make a mistake and e.g. render your Maple unable to + communicate with the IDE. Know what you're doing, and proceed with + caution. + +.. highlight:: sh + +Setup +^^^^^ + +In order to follow these instructions, you will need: + +- A binary of the bootloader you want to upload +- Hardware for communicating between the Maple and your computer over + serial. +- `Python <http://python.org>`_ version 2.5 or higher, with the + `PySerial <http://pyserial.sourceforge.net/>`_ library installed. + +**Step 1: Obtain a bootloader binary**. The first thing you'll need to +do is to compile your bootloader binary. Note that an ASCII +representation of the binary, such as the Intel .hex format, will not +suffice. For example, you can run (on a :ref:`suitably configured +system <unix-toolchain>`) the following to obtain a binary of the +bootloader currently used on the Maple:: + + $ git checkout git://github.com/leaflabs/maple-bootloader.git + $ cd maple-bootloader + $ make + $ ls -lh build/maple-boot.bin # this is the compiled bootloader binary + +**Step 2: Connect Maple Serial1 to your computer**. +There are a variety of ways of doing this. We use Sparkfun's `FTDI +breakout boards <http://www.sparkfun.com/products/718>`_, but you +could use another Maple, an Arduino, etc. -- anything that allows your +computer to communicate with the Maple you want to reprogram over a +serial interface. + +If you do use an FTDI breakout board, first make sure your Maple is +disconnected from an external power source, be it battery, USB, or +barrel jack. Then, connect the FTDI board's TX pin to ``Serial1``\ 's +RX pin (pin 8), FTDI RX to ``Serial1`` TX (pin 7), FTDI ground to +Maple's GND, and its 3.3V pin to Maple's Vin (use the Maple's +silkscreen for help locating these pins). At this point, you're ready +to plug the FTDI board into your computer (via USB). + +The ``Serial1`` pins are documented :ref:`here <lang-serial>`. + +**Step 3: Put your Maple into serial bootloader mode**. Do this by +pressing the RESET button, then *while RESET is held down*, pressing +and holding the BUT button. Next, *making sure to keep BUT held +down*, release the RESET button and wait for a few seconds before +releasing BUT. + +**Step 4: Obtain stm32loader.py**. The +script ``stm32loader.py`` is provided with libmaple. If you have set +up the :ref:`Unix toolchain <unix-toolchain>`, it is available in +libmaple/support/stm32loader.py. Otherwise, you can download it +directly from `github +<https://github.com/leaflabs/libmaple/raw/master/support/stm32loader.py>`_ +(click the link, then save the file somewhere on your system). + +Flashing the new Bootloader +^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +We'll use ``new-boot.bin``, ``ser-port``, and ``stm32loader.py`` to +respectively refer to the absolute paths to the bootloader binary +(from Step 1), the serial port device file or COMM port (from Steps 2 +and 3), and the stm32loader.py script. + +.. highlight:: sh + +You can run :: + + $ python stm32loader.py -h + +to obtain usage information. The incantation for uploading a +bootloader binary ``new-bootloader.bin`` is :: + + $ python stm32loader.py -p ser-port -evw new-boot.bin + +If all goes well, you'll see a bunch of output, then "Verification +OK". If something goes wrong, the `forum`_ is probably your best bet +for obtaining help, with IRC (irc.freenode.net, #leafblowers) being +another option. If all else fails, you can always `contact us +directly`_! diff --git a/docs/source/compatibility.rst b/docs/source/compatibility.rst index 8872a1b..848a3d3 100644 --- a/docs/source/compatibility.rst +++ b/docs/source/compatibility.rst @@ -17,10 +17,13 @@ that the Maple uses a 32-bit ARM Cortex-M3 architecture chip while the Arduinos have 8-bit Atmel AVR chips. The different instruction set means that machine code (executable binary programs) is incompatible between the two, and a different compiler (actually just a different -version of `gcc <http://gcc.gnu.org/>`_) is required. The compiler for -the regular Arduino IDE is the popular :command:`avr-gcc` package; the -compiler for the Maple version of the IDE is CodeSourcery's edition of -gcc for the ARM EABI target (:command:`arm-non-eabi-gcc`). +version of `gcc <http://gcc.gnu.org/>`_) is required. + +The compiler for the regular Arduino IDE is the popular +:command:`avr-gcc` package; the compiler for the Maple version of the +IDE is CodeSourcery's edition of gcc for the ARM EABI target +(:command:`arm-non-eabi-gcc`). A (preliminary) reference on +:ref:`using arm-none-eabi-gcc <arm-gcc>` is available. The bitwidth of the processor means that the Maple can process 32-bit operations (like adding two 32-bit integers) in a single instruction, @@ -45,8 +48,8 @@ numbered separately (A0-A5) from the digital pins (D0\ -D13). The incompatible hardware differences are: -* |i2c| port: on most Arduinos, the |i2c| port is Analog Input - 4 (SDA) and Analog Input 5 (SCL); on the Maple, |i2c| port 1 is D5 +* **I2C port**: on most Arduinos, the |i2c| port is Analog Input 4 + (SDA) and Analog Input 5 (SCL); on the Maple, |i2c| port 1 is D5 (SCL) and D9 (SDA), and |i2c| port 2 is D29 (SCL) and D30 (SDA). It should be possible to skywire, sacrificing signal quality (due to @@ -54,81 +57,210 @@ The incompatible hardware differences are: reasonably well in software. This peripheral could potentially be rerouted internally, but we haven't looked into it. -* :ref:`PWM <pwm>` on D10: all the other standard Arduino PWM headers have PWM - functionality on the Maple (D2,D3,D6,D9,D11), but not D10. We did - our best! It may be possible to reroute this peripheral internally - using low level configuration, but we haven't looked in to it. +* :ref:`PWM <pwm>` **on D10**: all the other standard Arduino PWM + headers have PWM functionality on the Maple (D2,D3,D6,D9,D11), but + not D10. We did our best! It may be possible to reroute this + peripheral internally using low level configuration, but we haven't + looked in to it. -* No External Voltage Reference: The Arduino has an Aref pin which +* **No External Voltage Reference**: The Arduino has an Aref pin which allows the use of an external ADC voltage reference; the Maple has an extra GPIO pin (14) with PWM capability in this spot, and does not allow an external voltage reference to be configured. -* EEPROM: the Maple does not have any internal EEPROM. This +* **EEPROM**: the Maple does not have any internal EEPROM. This functionality can be emulated with regular persistent flash memory, or with an external EEPROM chip. -* ISP Programming: the Maple does not use an ISP/ICSP bus for +* **ISP Programming**: the Maple does not use an ISP/ICSP bus for debugging; it uses :ref:`JTAG <jtag>`. Software Language/Library Changes --------------------------------- -With :ref:`one notable exception <language-no-word>`, the entire -Arduino language is supported. However, there are some subtle +With :ref:`a few exceptions <language-missing-features>`, the entire +Wiring/Arduino language is supported. However, there are some subtle differences, most of which are improvements: -* 32-bit integers: many standard functions either expect or return +* **32-bit integers**: many standard functions either expect or return full 32-bit (4 byte) integer values instead of the regular 16-bit (2 byte) Arduino values. -* `pinMode()`_ types: any :ref:`GPIO <gpio>` (including analog pins) - can be configured into one of the following modes with a single call - to `pinMode()`_: ``OUTPUT``, ``OUTPUT_OPEN_DRAIN``, - ``INPUT_FLOATING``, ``INPUT_PULLUP``, +* **64-bit doubles**: The :ref:`double <lang-double>` type is a full + double-precision floating point type on the Maple; it is a + single-precision floating point value on the Arduino. + +* :ref:`pinMode() <lang-pinmode>` **types**: any :ref:`GPIO <gpio>` + (including analog pins) can be configured into one of the following + modes with a single call to ```pinMode()``: ``OUTPUT``, + ``OUTPUT_OPEN_DRAIN``, ``INPUT_FLOATING``, ``INPUT_PULLUP``, ``INPUT_PULLDOWN``. Additionally, the PWM and Analog Input pins can be configured as ``INPUT_ANALOG`` and ``PWM`` respectively. See the :ref:`GPIO documentation <gpio>` for more information. - .. TODO: reference libmaple docs above when they're done - -* Serial1 syntax: like the `Arduino Mega +* :ref:`Serial port <lang-serial>` **syntax**: like the `Arduino Mega <http://arduino.cc/en/Main/ArduinoBoardMega>`_, the Maple has - multiple USART ports. By default, Serial is not mapped to any of - them, use ``Serial1`` through ``Serial3`` instead. - - .. TODO: reference libmaple docs for Serial[n] above when they're done - -* 16-bit :ref:`PWM <pwm>`: Arduino boards support 8-bit PWM, which - means that calls to `analogWrite()`_ take values between 0 (always - off) and 255 (always on). The Maple supports 16-bit PWM, so the - corresponding values should be between 0 (always off) and 65535 - (always on). - -* 12-bit :ref:`ADC <adc>`: Arduino boards support 10-bit ADC, which - means that calls to `analogRead()`_ will return values between 0 and - 1023. The Maple supports 12-bit ADC, so the same call will instead - return values between 0 and 4095. - - -.. class:: ported-feature + multiple :ref:`USART ports <lang-serial>`. By default, ``Serial`` + is not mapped to any of them, use ``Serial1`` through ``Serial3`` + instead. -I am supported! +* **16-bit** :ref:`PWM <pwm>`: Arduino boards support 8-bit PWM, which + means that calls to :ref:`analogWrite() <lang-analogwrite>` take + values between 0 (always off) and 255 (always on). The Maple + supports 16-bit PWM, so the corresponding values should be between 0 + (always off) and 65535 (always on). -This should be ordinary +* **12-bit** :ref:`ADC <adc>`: Arduino boards support 10-bit ADC, which + means that calls to :ref:`analogRead() <lang-analogread>` will + return values between 0 and 1023. The Maple supports 12-bit ADC, so + the same call will instead return values between 0 and 4095. -.. class:: non-ported-feature +Shield and Device Compatibility +------------------------------- -I can't do it :( +.. list-table:: + :header-rows: 1 -Also ordinary + * - Shield/Device + - Compatible? + - Notes -.. class:: partly-ported-feature + * - Ethernet shield + - Yes! + - Tested; no library yet -I sorta work + * - WiFi Shield + - Yes! + - Tested; preliminary library support -And I am also ordinary + * - MIDI shield + - Yes! + - Tested; no library yet + + * - XBee shield + - Unknown + - + + * - Bluetooth shield + - Unknown + - Some Bluetooth <-> UART boards have been tested and are known + to work. + + * - Cellular shield + - Unknown + - + +Library Porting Status +---------------------- + +The state of currently ported Arduino libraries is the +:ref:`libraries`. + +.. TODO Update as libraries are ported. + +.. list-table:: + :header-rows: 1 + + + * - Library + - Ported? + - Notes + + * - Wire + - Preliminary + - In progress; see :ref:`library reference <libraries-wire>`. + + * - LiquidCrystal + - **Yes** + - :ref:`Included since IDE 0.0.7 <libraries-liquid-crystal>` + + * - Ethernet + - Not yet + - Planned + + * - EEPROM + - (Unsupported) third-party emulation + - The Maple doesn't have EEPROM; it uses flash instead. There is + an `EEPROM emulation library + <http://akb77.com/g/mcu/maple-eeprom-emulation-library/>`_ by + `x893 <http://akb77.com/g/>`_, but we haven't tested it. + + * - Firmata + - Not yet + - Planned + + * - Matrix + - Not yet + - Planned + + * - Servo + - **Yes** + - :ref:`Included since IDE 0.0.9 <libraries-servo>` + + * - SoftwareSerial + - Not yet + - Planned + + * - Sprite + - Not yet + - Planned + + * - Stepper + - Not yet + - Planned -Stub (unfinished) +Sketch and Library Porting HOWTO +-------------------------------- + +In addition to the suggestions in this section, you may find many of +the individual :ref:`language reference <language>` pages useful. As +appropriate, these have "Arduino Compatibility" sections; one good +example is the :ref:`analogWrite() <lang-analogwrite-compatibility>` +function. +- Check the hardware and header differences above, and see if your + project or shield needs to be modified (eg, add 3.3V level + converters or reroute PWM to header D10). + +- Check for ported library functionality. We intend to port all of the + core and popular libraries (like Wire, Ethernet, and the LCD screen + driver), but this task is not yet finished. (Patches are welcome!) + +- Check for peripheral conflicts; changing the configuration of timers + and bus speeds for a feature on one header may impact all the + features on that hardware "port". For example, changing the timer + prescaler to do long PWM pulses could impact |i2c| communications on + nearby headers. + +- Rewrite any low-level code. This could potentially be very + difficult, but hopefully you've used the Arduino libraries to + abstract away the registers and other hardware-specific + details. Your sketch probably doesn't have any low-level code; a + library which wraps a particular peripheral very well may. Some + help is available in the :ref:`arm-gcc` reference. + +- Redeclare variable sizes if necessary: generics like ``int`` will + probably work unless you depend on side-effects like rollover. + +- Check every ``pinMode()``: the Maple has more modes for GPIO + pins. For example, make sure to set analog pins to ``INPUT_ANALOG`` + before reading and PWM pins to ``PWM`` before writing. The full set + of pin modes is documented in the :ref:`lang-pinmode` reference. + +- Modify PWM writes: ``pinMode()`` must be set to ``PWM``, the + frequency of the PWM pulse configured, and the duty cycle written + with up to 16-bit resolution. + +- Modify ADC reads: :ref:`lang-analogread` takes the full pin number + (not 0-5) and returns a full 12-bit reading. The ADC pin must have + its ``pinMode()`` set to ``INPUT_ANALOG``. + +- Possibly convert all Serial-over-USB communications to use + :ref:`lang-serialusb` instead of a USART :ref:`serial port + <lang-serial>`. The Maple has a dedicated USB port which is not + connected to the USART TX/RX pins in any way. + +- Check timing: Maple clock cycles are just 13.9 nanoseconds, though + the peripheral bus speeds (which limit GPIO output) are clocked + slower. diff --git a/docs/source/conf.py b/docs/source/conf.py index e1aa3a4..1ad4e57 100644 --- a/docs/source/conf.py +++ b/docs/source/conf.py @@ -37,7 +37,7 @@ extensions = ['sphinx.ext.autodoc', 'sphinx.ext.doctest', 'sphinx.ext.coverage', 'breathe'] # Add any paths that contain templates here, relative to this directory. -templates_path = ['_templates'] +templates_path = ['_templates', '_static'] # The suffix of source filenames. source_suffix = '.rst' @@ -59,7 +59,7 @@ copyright = u'2010, LeafLabs, LLC' # The short X.Y version. version = '0.0' # The full version, including alpha/beta/rc tags. -release = '0.0.7' +release = '0.0.9' # The language for content autogenerated by Sphinx. Refer to documentation # for a list of supported languages. @@ -69,7 +69,7 @@ release = '0.0.7' # non-false value, then it is used: #today = '' # Else, today_fmt is used as the format for a strftime call. -#today_fmt = '%B %d, %Y' +today_fmt = '%B %d, %Y' # List of patterns, relative to source directory, that match files and # directories to ignore when looking for source files. @@ -88,7 +88,7 @@ with open('prolog.rst', 'r') as pr: #default_role = None # If true, '()' will be appended to :func: etc. cross-reference text. -#add_function_parentheses = True +add_function_parentheses = True # If true, the current module name will be prepended to all description # unit titles (such as .. function::). @@ -105,7 +105,7 @@ pygments_style = 'sphinx' #modindex_common_prefix = [] # Warn about all references where the target cannot be found. -#nitpicky = True +nitpicky = True # -- Options for HTML output -------------------------------------------------- @@ -116,26 +116,46 @@ html_theme = 'default' # Theme options are theme-specific and customize the look and feel of a theme # further. For a list of options available for each theme, see the # documentation. -#html_theme_options = {} +html_theme_options = { + ## Sidebar placement options + #'stickysidebar' : 'true', + 'rightsidebar' : 'true', + #'collapsiblesidebar' : 'true', + + ## Color + 'sidebarbgcolor' : '#C8C8C8', + 'sidebarlinkcolor' : 'green', + 'sidebartextcolor' : 'black', + #'sidebarbtncolor' : 'black', + 'footerbgcolor' : 'green', + 'relbarbgcolor' : 'green', + 'headlinkcolor' : '#000000', + 'linkcolor' : 'green', + 'visitedlinkcolor' : 'green', + + ## Font + 'headfont' : 'Georgia', + 'bodyfont' : 'Lucidia' +} # Add any paths that contain custom themes here, relative to this directory. -#html_theme_path = [] +#html_theme_path = ['_static'] # The name for this set of Sphinx documents. If None, it defaults to # "<project> v<release> documentation". -#html_title = None +html_title = project + ' v' + release + ' Documentation' # A shorter title for the navigation bar. Default is the same as html_title. -#html_short_title = None +html_short_title = 'Index' # The name of an image file (relative to this directory) to place at the top # of the sidebar. -#html_logo = None +html_logo = '_static/img/round_logo_60x60.png' # The name of an image file (within the static path) to use as favicon of the # docs. This file should be a Windows icon file (.ico) being 16x16 or 32x32 # pixels large. -#html_favicon = None +html_favicon = '_static/img/round_logo_32x32.ico' # Add any paths that contain custom static files (such as style sheets) here, # relative to this directory. They are copied after the builtin static files, @@ -144,14 +164,19 @@ html_static_path = ['_static'] # If not '', a 'Last updated on:' timestamp is inserted at every page bottom, # using the given strftime format. -#html_last_updated_fmt = '%b %d, %Y' +html_last_updated_fmt = '%b %d, %Y' # If true, SmartyPants will be used to convert quotes and dashes to # typographically correct entities. #html_use_smartypants = True # Custom sidebar templates, maps document names to template names. -#html_sidebars = {} +# re-add commented line when custom template for api finished +html_sidebars = { + '**': ['globaltoc.html', 'searchbox.html'], + #'lang/api**':['searchbox.html', 'apilist.html'], +} + # Additional templates that should be rendered to pages, maps page names to # template names. @@ -161,7 +186,7 @@ html_static_path = ['_static'] #html_domain_indices = True # If false, no index is generated. -#html_use_index = True +html_use_index = False # If true, the index is split into individual pages for each letter. #html_split_index = False diff --git a/docs/source/epilog.rst b/docs/source/epilog.rst index 4234dd9..e64103c 100644 --- a/docs/source/epilog.rst +++ b/docs/source/epilog.rst @@ -6,56 +6,3 @@ .. _forum: http://forums.leaflabs.com .. _contact: http://leaflabs.com/contact/ .. _contact us directly: http://leaflabs.com/contact/ - -.. Arduino built-in functions - -.. _setup(): http://arduino.cc/en/Reference/Setup -.. _loop(): http://arduino.cc/en/Reference/Loop - -.. _pinMode(): http://arduino.cc/en/Reference/PinMode -.. _digitalWrite(): http://arduino.cc/en/Reference/DigitalWrite -.. _digitalRead(): http://arduino.cc/en/Reference/DigitalRead - -.. _analogReference(): http://arduino.cc/en/Reference/AnalogReference -.. _analogRead(): http://arduino.cc/en/Reference/AnalogRead -.. _analogWrite(): http://arduino.cc/en/Reference/AnalogWrite - -.. _tone(): http://arduino.cc/en/Reference/Tone -.. _noTone(): http://arduino.cc/en/Reference/NoTone -.. _shiftOut(): http://arduino.cc/en/Reference/ShiftOut -.. _pulseIn(): http://arduino.cc/en/Reference/PulseIn - -.. _millis(): http://arduino.cc/en/Reference/Millis -.. _micros(): http://arduino.cc/en/Reference/Micros -.. _delay(): http://arduino.cc/en/Reference/Delay -.. _delayMicroseconds(): http://arduino.cc/en/Reference/DelayMicroseconds - -.. _min(): http://arduino.cc/en/Reference/Min -.. _max(): http://arduino.cc/en/Reference/Max -.. _abs(): http://arduino.cc/en/Reference/Abs -.. _constrain(): http://arduino.cc/en/Reference/Constrain - -.. _map(): http://arduino.cc/en/Reference/Map -.. _pow(): http://arduino.cc/en/Reference/Pow -.. _sqrt(): http://arduino.cc/en/Reference/Sqrt - -.. _sin(): http://arduino.cc/en/Reference/Sin -.. _cos(): http://arduino.cc/en/Reference/Cos -.. _tan(): http://arduino.cc/en/Reference/Tan - -.. _randomSeed(): http://arduino.cc/en/Reference/RandomSeed -.. _random(): http://arduino.cc/en/Reference/Random - -.. _lowByte(): http://arduino.cc/en/Reference/LowByte -.. _highByte(): http://arduino.cc/en/Reference/HighByte -.. _bitRead(): http://arduino.cc/en/Reference/BitRead -.. _bitWrite(): http://arduino.cc/en/Reference/BitWrite -.. _bitSet(): http://arduino.cc/en/Reference/BitSet -.. _bitClear(): http://arduino.cc/en/Reference/BitClear -.. _bit(): http://arduino.cc/en/Reference/Bit - -.. _attachInterrupt(): http://arduino.cc/en/Reference/AttachInterrupt -.. _detachInterrupt(): http://arduino.cc/en/Reference/DetachInterrupt - -.. _interrupts(): http://arduino.cc/en/Reference/Interrupts -.. _noInterrupts(): http://arduino.cc/en/Reference/NoInterrupts diff --git a/docs/source/errata.rst b/docs/source/errata.rst index 4b03513..a3bb66a 100644 --- a/docs/source/errata.rst +++ b/docs/source/errata.rst @@ -7,10 +7,148 @@ This page is a collection of known issues and warnings for each revision of the Maple board. The failure modes aren't design errors, but are easy ways to break or damage your board permanently. For a -list of differences between the Maple and Arduinos, see the page on -:ref:`compatibility <compatibility>`. +list of differences between the Maple and Arduinos, see the +:ref:`compatibility reference <compatibility>`. .. contents:: Contents :local: -Stub. +Maple Rev 5 +----------- + +These boards went on sale in November 2010. They have white buttons, +and "r5" in small print near the "LeafLabs Maple" text next to the +"infinity-leaf" logo, among other changes: + +.. figure:: /_static/img/maple_rev5.png + :align: center + :alt: Maple Rev 5 + +Known issues: + +* **GPIO 39-43 not configured**: this is really more of a software + "TODO" item. Some of the JTAG header pins are numbered 39-43. These + STM32 pins are indeed fully functional :ref:`GPIO <gpio>` when the a + :ref:`JTAG <jtag>` device is not connected, but we have not enabled + them in software and thus they can not be accessed with the regular + :ref:`lang-pinmode` or :ref:`lang-digitalwrite` functions. + +Potential failure modes: + +* **TTL voltage on non-tolerant pins**: not all header pins are 5V + compatible; connecting certain serial devices in the wrong way could + over voltage the pins. The :ref:`Pin-Mapping Mega Table + <pin-mapping-mega-table>` details which pins are 5V-tolerant. + +Maple Rev 3 +----------- + +This batch of boards went on sale beginning in May 2010. They have a +darker red silkscreen and the "infinity-leaf" logo: + +.. figure:: /_static/img/maple_rev3.png + :align: center + :alt: Maple Rev 3 + +Known issues: + +* **Bad/Sticky Buttons**: a number of Rev 3 boards sold in May-June 2010 + have questionable RESET and BUT buttons. + + What seems to have happened is that the flux remover we used to + clean the boards before shipping eroded the plastic internals, which + resulted in intermittent functionality. All buttons on all shipped + boards did function in testing, but some may have been unreliable in + regular use. + + If you have this problem, we will be happy to ship you new buttons + if you think you can re-solder them yourself, or you can ship us + your board and we will swap out that part. + + For reference, the button part number is KMR211GLFS and the flux + remover we used is "Precision Electronics Cleaner" from RadioShack, + which is "Safe on most plastics" and contains Dipropylene glycol + monomethyl ether, hydrotreated heavy naphtha, dipropylene glycol + methyl ether acetate (really?), and carbon dioxide. + +* **Resistors on pins 0 and 1**: these header pins, which are RX/TX on + USART2 (:ref:`Serial2 <lang-serial>`), have resistors in-line + between the STM32 and the headers. These resistors increase the + impedance of the lines for ADC reads and affect the open drain GPIO + functionality of the pins. + + These resistors were accidentally copied over from older Arduino USB + designs, where they appear to protect the USB-Serial converter from + TTL voltage on the headers. + +* **GPIO 39-43 not configured**: this is really more of a software + "TODO" item. Some of the JTAG header pins are numbered 39-43. These + STM32 pins are indeed fully functional :ref:`GPIO <gpio>` when the a + :ref:`JTAG <jtag>` device is not connected, but we have not enabled + them in software and thus they can not be accessed with the regular + :ref:`lang-pinmode` or :ref:`lang-digitalwrite` functions. + +* **Silkscreen Errors**: the silkscreen on the bottom indicated PWM + functionality on pin 25 and listen the external header GND pin as + number 38 (actually 38 is connected to the BUT button). We manually + sharpied over both of these mistakes. + +* **PWM Marketing Mistake**: We originally sold the Maple advertising + 22 channels of 16-bit hardware PWM; actually the Maple only has 15. + +Potential failure modes: + +* **TTL voltage on non-tolerant pins**: not all header pins are 5V + compatible; connecting certain serial devices in the wrong way could + over voltage the pins. The :ref:`Pin-Mapping Mega Table + <pin-mapping-mega-table>` details which pins are 5V-tolerant. + +Maple Rev 1 +----------- + +This batch of 100 boards shipped in later 2009. They have a red +silkscreen and the logo is a single pixelated leaf: + +.. figure:: /_static/img/maple_rev1.png + :align: center + :alt: Maple Rev 1 + +Known issues: + +* **ADC noise**: generally very high, in particular when the USB port + is being used for communications (including keep-alive pings when + connected to a computer). + + This issue was resolved in Rev 3 with a 4-layer design and a + geometrically isolated ADC V\ :sub:`ref` plane. + +* **Resistors on pins 0 and 1**: these header pins, which are RX/TX on + USART2 (:ref:`Serial2 <lang-serial>`), have resistors in-line + between the STM32 and the headers. These resistors increase the + impedance of the lines for ADC reads and affect the open drain GPIO + functionality of the pins. + + These resistors were accidentally copied over from older Arduino USB + designs, where they appear to protect the USB-Serial converter from + TTL voltage on the headers. + +* **Silkscreen Differences**: the pin numbering scheme on Rev 1 is + different from Rev 3, and thus Rev 3 software is difficult to use + with Rev 1 boards. Notably, the analog input bank is labeled A0-A4 + on Rev 1 but 15-20 on Rev 3, and the extra header bank does not have + a pinout table on the bottom. + +* **No BUT Button**: the BUT button, useful for serial bootloading, + was only added in Rev 3. As a workaround, you can directly short the + appropriate MCU pin to Vcc; see `this forum posting + <http://forums.leaflabs.com/topic.php?id=32#post-126>`_. + +* **PWM Marketing Mistake**: We originally sold the Maple advertising + 22 channels of 16-bit hardware PWM; actually the Maple only has 15. + +Potential failure modes: + +* **TTL voltage on non-tolerant pins**: not all header pins are 5v + compatible; connecting certain serial devices in the wrong way could + over voltage the pins. The :ref:`Pin-Mapping Mega Table + <pin-mapping-mega-table>` details which pins are 5V-tolerant. diff --git a/docs/source/external-interrupts.rst b/docs/source/external-interrupts.rst index bc9d6cd..5187ca4 100644 --- a/docs/source/external-interrupts.rst +++ b/docs/source/external-interrupts.rst @@ -76,7 +76,7 @@ The following table shows which pins can be used on which lines. .. note:: - You should set the :ref:`pin mode <arduino-pinmode>` of your + You should set the :ref:`pin mode <lang-pinmode>` of your desired pin to an input mode (e.g ``INPUT`` or ``INPUT_FLOATING``, ``INPUT_PULLUP``, ``INPUT_PULLDOWN``). @@ -121,6 +121,5 @@ Recommended Reading * STMicro documentation for STM32F103RB microcontroller: - * `All <http://www.st.com/mcu/devicedocs-STM32F103RB-110.html>`_ * `Datasheet <http://www.st.com/stonline/products/literature/ds/13587.pdf>`_ (pdf) - * `Reference Manual <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (pdf) + * `Reference Manual <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (pdf) diff --git a/docs/source/foo.rst b/docs/source/foo.rst deleted file mode 100644 index 769e666..0000000 --- a/docs/source/foo.rst +++ /dev/null @@ -1,114 +0,0 @@ -.. _foo: - -================================== -[temporary] Converted Arduino docs -================================== - -This is the index of the imported Arduino docs. - -.. toctree:: - :maxdepth: 2 - - abs() <arduino/abs> - analogRead() <arduino/analogread> - pinMode() <arduino/pinmode> - Arithmetic <arduino/arithmetic> - Arrays <arduino/array> - Assignment <arduino/assignment> - attachInterrupt() <arduino/attachinterrupt> - bit <arduino/bit> - -.. bitclear <arduino-bitclear> -.. bitread <arduino-bitread> -.. bitset <arduino-bitset> -.. bitshift <arduino-bitshift> -.. bitwiseand <arduino-bitwiseand> -.. bitwisecompound <arduino-bitwisecompound> -.. bitwisexornot <arduino-bitwisexornot> -.. bitwrite <arduino-bitwrite> -.. boolean <arduino-boolean> -.. booleanvariables <arduino-booleanvariables> -.. braces <arduino-braces> -.. break <arduino-break> -.. byte <arduino-byte> -.. bytecast <arduino-bytecast> -.. changes <arduino-changes> -.. char <arduino-char> -.. charcast <arduino-charcast> -.. comments <arduino-comments> -.. comparison <arduino-comparison> -.. const <arduino-const> -.. constants <arduino-constants> -.. constrain <arduino-constrain> -.. continue <arduino-continue> -.. cos <arduino-cos> -.. define <arduino-define> -.. delay <arduino-delay> -.. delaymicroseconds <arduino-delaymicroseconds> -.. detachinterrupt <arduino-detachinterrupt> -.. digitalread <arduino-digitalread> -.. digitalwrite <arduino-digitalwrite> -.. double <arduino-double> -.. dowhile <arduino-dowhile> -.. else <arduino-else> -.. float <arduino-float> -.. floatcast <arduino-floatcast> -.. for <arduino-for> -.. fpconstants <arduino-fpconstants> -.. goto <arduino-goto> -.. highbyte <arduino-highbyte> -.. homepage <arduino-homepage> -.. if <arduino-if> -.. include <arduino-include> -.. increment <arduino-increment> -.. incrementcompound <arduino-incrementcompound> -.. int <arduino-int> -.. intcast <arduino-intcast> -.. integerconstants <arduino-integerconstants> -.. interrupts <arduino-interrupts> -.. libraries <arduino-libraries> -.. long <arduino-long> -.. longcast <arduino-longcast> -.. loop <arduino-loop> -.. lowbyte <arduino-lowbyte> -.. map <arduino-map> -.. max <arduino-max> -.. micros <arduino-micros> -.. millis <arduino-millis> -.. min <arduino-min> -.. modulo <arduino-modulo> -.. nointerrupts <arduino-nointerrupts> -.. notone <arduino-notone> -.. pointer <arduino-pointer> -.. pow <arduino-pow> -.. pulsein <arduino-pulsein> -.. random <arduino-random> -.. randomseed <arduino-randomseed> -.. return <arduino-return> -.. scope <arduino-scope> -.. semicolon <arduino-semicolon> -.. serial <arduino-serial> -.. setup <arduino-setup> -.. shiftout <arduino-shiftout> -.. sin <arduino-sin> -.. sizeof <arduino-sizeof> -.. sqrt <arduino-sqrt> -.. static <arduino-static> -.. string <arduino-string> -.. stringobject <arduino-stringobject> -.. switchcase <arduino-switchcase> -.. tan <arduino-tan> -.. tone <arduino-tone> -.. unsignedchar <arduino-unsignedchar> -.. unsignedint <arduino-unsignedint> -.. unsignedlong <arduino-unsignedlong> -.. void <arduino-void> -.. volatile <arduino-volatile> -.. while <arduino-while> -.. word <arduino-word> -.. wordcast <arduino-wordcast> - -.. TODO later - -.. analogreference() <arduino/analogreference> -.. analogWrite() <arduino/analogwrite> diff --git a/docs/source/gpio.rst b/docs/source/gpio.rst index 7a9031a..4017862 100644 --- a/docs/source/gpio.rst +++ b/docs/source/gpio.rst @@ -1,8 +1,7 @@ .. _gpio: -====== - GPIO -====== +GPIO +==== The Maple features 38 ready-to-use general purpose input/output (GPIO) pins for digital input/output, numbered D0 through D37. These numbers @@ -15,9 +14,9 @@ peripheral functions. This page documents those capabilities, by pin. The current and voltage limitations have not been copied over from the STM32 datasheet (see the :ref:`Recommended Reading <gpio-recommended-reading>` for a link). In particular, a number of -GPIO pins are 5v tolerant (which means that applying 5v to a pin and -reading it as input or allowing it to drain to ground will not damage -that pin), while some are not. +GPIO pins are 5V tolerant (which means that applying 5 volts to a pin +and reading it as input or allowing it to drain to ground will not +damage that pin), while some are not. .. contents:: Contents :local: @@ -27,11 +26,10 @@ that pin), while some are not. Pin Mapping Mega Table ---------------------- -This huge reference table shows the available functionality on every -GPIO pin, by peripheral type. The "STM32" column refers to the port -and number that the header is connected to on the microcontroller. -The "5v?" column documents whether or not the pin is 5v tolerant (see -above). +This table shows the available functionality on every GPIO pin, by +peripheral type. The "STM32" column refers to the port and number that +the header is connected to on the microcontroller. The "5V?" column +documents whether or not the pin is 5 volt tolerant (see above). .. csv-table:: :header: "Pin", "STM32", ":ref:`ADC <adc>`", ":ref:`Timer <timers>`", ":ref:`I2C <i2c>`", ":ref:`UART <usart>`", ":ref:`SPI <spi>`", "5v?" @@ -80,7 +78,7 @@ above). GPIO Modes ---------- -.. doxygenenum:: WiringMode +.. doxygenenum:: WiringPinMode Function Reference ------------------ @@ -100,6 +98,5 @@ Recommended Reading STMicro documentation for STM32F103RB microcontroller: - * `All <http://www.st.com/mcu/devicedocs-STM32F103RB-110.html>`_ * `Datasheet <http://www.st.com/stonline/products/literature/ds/13587.pdf>`_ (pdf) * `Reference Manual <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (pdf) diff --git a/docs/source/hardware.rst b/docs/source/hardware.rst deleted file mode 100644 index 1fa3554..0000000 --- a/docs/source/hardware.rst +++ /dev/null @@ -1,24 +0,0 @@ -.. _hardware: - -================================= - Hardware-Specific Documentation -================================= - -This page indexes the Maple's capabilities for interacting with -external hardware peripherals. For information about a particular -device or protocol, see its individual reference page. - -Individual reference pages: - -.. toctree:: - :maxdepth: 2 - - i2c - pwm - gpio - usb - jtag - adc - spi - usart - timers diff --git a/docs/source/i2c.rst b/docs/source/i2c.rst index ddb2ac9..b4a996b 100644 --- a/docs/source/i2c.rst +++ b/docs/source/i2c.rst @@ -6,7 +6,7 @@ .. note:: - The i2c interface is currently only available from the 'i2c' branch + The |i2c| interface is currently only available from the 'i2c' branch of the github `libmaple <http://github.com/leaflabs/libmaple>`_ repository. @@ -80,7 +80,6 @@ Recommended Reading * `Arduino i2c/TWI reference <http://www.arduino.cc/playground/Learning/I2C>`_ * STMicro documentation for STM32F103RB microcontroller: - * `All <http://www.st.com/mcu/devicedocs-STM32F103RB-110.html>`_ * `Datasheet <http://www.st.com/stonline/products/literature/ds/13587.pdf>`_ (pdf) * `Reference Manual <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (pdf) * `Application Note on Advanced I2C Usage diff --git a/docs/source/ide.rst b/docs/source/ide.rst new file mode 100644 index 0000000..b3ef653 --- /dev/null +++ b/docs/source/ide.rst @@ -0,0 +1,136 @@ +.. _ide: + +Maple IDE +========= + +This page documents the basic functionality of the Maple IDE. +Specifically, it describes the operation of the buttons on the main +toolbar. It is expected to become more comprehensive over time. + +The :ref:`Maple Quickstart <maple-quickstart>` is another good source of +information on the IDE; it is especially useful for setting up a +computer for the first time. + +.. figure:: /_static/img/ide-blinky.png + :align: center + :alt: Maple IDE + +.. _ide-verify: + +Verify +------ + +.. image:: /_static/img/button-verify.png + :align: left + +Click Verify to compile the current sketch. + +.. _ide-stop: + +Stop +---- + +.. image:: /_static/img/button-stop.png + :align: left + +Click Stop to cancel a compilation. + +.. _ide-new: + +New +--- + +.. image:: /_static/img/button-new.png + :align: left + +Click New to begin a fresh sketch. + +.. _ide-open: + +Open +---- + +.. image:: /_static/img/button-open.png + :align: left + +Click Open to open a new sketch. By default, this will look in you +*sketchbook*, which is a directory on your system which contains all +of your sketches. The default directory of your sketchbook varies by +operating system; you can change it in the IDE preferences. + +.. _ide-save: + +Save +---- + +.. image:: /_static/img/button-save.png + :align: left + +Click Save to save the currently opened sketch. + +.. _ide-upload: + +Upload +------ + +.. image:: /_static/img/button-upload.png + :align: left + +Click Upload to send the compiled sketch to your Maple to run. Before +you click Upload, you must have a memory location and serial port +selected. The memory location, either Flash or RAM, determines +whether the compiled sketch binary will be stored on the Maple. You +can choose this using the Tools > Board menu. The serial port +corresponds to the Serial-over-USB connection the Maple has +established with your computer. This looks like "COM1", "COM2", +etc. on Windows, "/dev/tty.usbmodemXXX" on Mac (where "XXX" is some +sequence of letters and numbers), or "/dev/ttyACMXXX" on Linux (again, +where "XXX" is some sequence of letters and numbers). You can choose +a serial port using the Tools > Serial Port menu. + +If you click Upload without having made these choices; The IDE +*should* prompt you to do so. However, if you're trying to upload and +are unsuccessful, make sure you've made choices for both board and +serial port. + +For more help, the upload process is documented in more detail (with +screenshots) in the :ref:`quickstart <maple-quickstart-upload>`. + +If all else fails, try putting your Maple in :ref:`perpetual +bootloader mode <troubleshooting-perpetual-bootloader>` before +uploading. + +In any case, you can always find us on the `forum`_ or `contact us +directly`_. + +.. _ide-serial-monitor: + +Serial Monitor +-------------- + +.. image:: /_static/img/button-serial-monitor.png + :align: left + +Click Serial Monitor to open up a communications channel between your +PC and the Maple's :ref:`Serial-over-USB <lang-serialusb>` +(``SerialUSB``) virtual serial port. + +If the serial monitor is open, any information sent to the computer +(e.g. using :ref:`SerialUSB.println() <lang-serialusb-println>` will +be displayed in the large text area. You can send data to the Maple +(to be read with e.g. :ref:`SerialUSB.read() <lang-serialusb-read>`) +by typing into the small text box and either hitting the Enter key or +pressing the Send button. + +Here is an example serial monitor session with the InteractiveTest +sketch (which you can load in the IDE by choosing menu item File > +Examples > Maple > InteractiveTest): + +.. image:: /_static/img/serial-monitor.png + +This is the result of typing "?" in the text box and clicking Send. + +.. note:: You cannot upload a sketch while the serial monitor is open. + If you click :ref:`Upload <ide-upload>` while the serial monitor is + open, the IDE will close it for you before proceeding with the + upload. diff --git a/docs/source/index.rst b/docs/source/index.rst index ac92d4b..825ec81 100644 --- a/docs/source/index.rst +++ b/docs/source/index.rst @@ -1,43 +1,70 @@ -.. libmaple documentation master file, created by - sphinx-quickstart on Thu Oct 7 06:42:30 2010. - You can adapt this file completely to your liking, but it should at least - contain the root `toctree` directive. - .. _index: -Maple Documentation Index -========================= +Maple Documentation Contents +============================ + +Welcome! This is the Maple documentation index. If you just bought a +Maple, you probably want to head to the :ref:`quickstart +<maple-quickstart>`. If you're having problems, check out the +:ref:`troubleshooting <troubleshooting>` and :ref:`known problems +<errata>` pages. -Welcome! This is the documentation index for programming your Maple. -It contains tutorials, quickstarts, and technical documentation. +Have fun! -If you just got a new Maple, you probably want to begin with the -:ref:`quickstart <maple-quickstart>`. You can then move on to reading -about the programming language you use with the Maple at the -:ref:`language reference <language>`. Good luck, and have fun! +.. _index-usage: -Table of contents: +**Usage Guides:** -.. TODO: be more Pythonic with a "parts of the documentation" thing .. toctree:: :maxdepth: 2 - Maple Quickstart Guide <maple-quickstart> - Maple IDE Installation Guide <maple-ide-install> - Maple/Arduino Compatibility Reference <compatibility> - Maple Language Reference <language> - Maple Library Reference <libraries> - libmaple Command-Line Tools and APIs <libmaple> - Troubleshooting <troubleshooting> - Hardware-Specific Documentation <hardware> + Quickstart <maple-quickstart> + IDE Installation <maple-ide-install> + IDE Anatomy <ide> + +.. _index-maple-programming: + +**Maple Programming:** + +.. toctree:: + :maxdepth: 2 + + Maple Language<language> + Maple Libraries <libraries> + Arduino Compatibility <compatibility> External Interrupts <external-interrupts> - Maple bootloader <bootloader> + Command-Line Tools & APIs <libmaple> + Bootloader <bootloader> + + + Troubleshooting <troubleshooting> Known Problems <errata> - [Temporary] Arduino docs TOC <foo> -Indices and tables -================== +.. _index-hardware: + +**Hardware Peripherals:** + +.. toctree:: + :maxdepth: 1 + + i2c + pwm + gpio + usb + jtag + adc + spi + usart + timers + +.. _index-reference: + +**Reference:** + +.. toctree:: + :maxdepth: 1 + + Technical Specifications <specs> + Complete Language Index <language-index> -* :ref:`genindex` -* :ref:`search` diff --git a/docs/source/jtag.rst b/docs/source/jtag.rst index 9b8ee14..e3c8111 100644 --- a/docs/source/jtag.rst +++ b/docs/source/jtag.rst @@ -15,24 +15,24 @@ and hardware peripherals (we use it when working on :ref:`libmaple Note that the STM32 on the Maple has a built-in low level serial debugger which could also be used to flash bootloaders, and that the :ref:`ASSERT <language-assert>` framework allows basic debugging over -a USART serial channel. We expect only advanced users to use this -feature. +a USART serial channel. We expect only fairly advanced users to use +this feature. .. contents:: Contents :local: - Wiring Diagram -------------- .. figure:: /_static/img/jtag-wiring.png :align: center :alt: JTAG wiring diagram + :width: 7.4in - JTAG wiring diagram to connect a standard 20-pin ARM JTAG device to - the 8-pin JTAG port on the Maple. - -.. TODO jtag wiring diagram (above) looks terrible; replace it + JTAG wiring diagram (`large version + <http://leaflabs.com/wp-content/uploads/2010/11/maple-jtagadapter.png>`_) + to connect a standard 20-pin ARM JTAG device to the 8-pin JTAG port + on the Maple. The Maple has holes for a 8-pin JTAG header but that header is not soldered on by default. If you know ahead of time that you'll be @@ -42,22 +42,14 @@ probably solder one on for no charge. Otherwise, you can simply attach standard 0.1" pitch male header pins (either the exact 4x2 block or two 4-pin pieces of breakaway straight header). For a one-off usage hack, the header can be jammed in the holes and twisted to -ensure electrical contact; this is what we do to flash our bootloader. - -The above schematic assumes that the header has been soldered on to -the *bottom* of the board, not the top; most ribbon cable connectors -will interfere with the power header. If you don't want a header -coming off the bottom, you can use a slim connector and invert this -diagram appropriately. - +ensure electrical contact. Compatible Devices ------------------ We have had good experience with the `Olimex ARM-USB-OCD <http://www.olimex.com/dev/arm-usb-ocd.html>`_ device, which costs -about 55 euro plus shipping (as of October 2010). - +about 55 euro plus shipping (as of November 2010). Recommended Reading ------------------- @@ -66,6 +58,8 @@ Recommended Reading * `STM32/gdb/OpenOCD HOWTO <http://fun-tech.se/stm32/OpenOCD/gdb.php>`_ * STMicro documentation for STM32F103RB microcontroller: - * `All <http://www.st.com/mcu/devicedocs-STM32F103RB-110.html>`_ * `Datasheet <http://www.st.com/stonline/products/literature/ds/13587.pdf>`_ (pdf) * `Reference Manual <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (pdf) +* There's a `thread on JTAG + <http://forums.leaflabs.com/topic.php?id=536>`_ in our `forum`_ + which you may find useful. diff --git a/docs/source/lang/api/abs.rst b/docs/source/lang/api/abs.rst new file mode 100644 index 0000000..0cc6c23 --- /dev/null +++ b/docs/source/lang/api/abs.rst @@ -0,0 +1,49 @@ +.. highlight:: cpp + +.. _lang-abs: + + +abs() +====== + +(Macro) computes the absolute value of a number. + +Syntax +------ + +:: + + abs(x) + +Parameters +---------- + +**x**: the number. + +Returns +------- + +**x**: if **x** is greater than or equal to 0. + +**-x**: if **x** is less than 0. + +Warning +------- + +Because of the way ``abs()`` is implemented, avoid using other +functions or causing side effects inside the parentheses, as it may +lead to incorrect results:: + + abs(a++); // avoid this - yields incorrect results + + abs(a); // use this instead - + a++; // keep other operations outside abs() + + +Arduino Compatibility +--------------------- + +Maple's implementation of ``abs()`` is compatible with Arduino. + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/analogread.rst b/docs/source/lang/api/analogread.rst new file mode 100644 index 0000000..35c6fbc --- /dev/null +++ b/docs/source/lang/api/analogread.rst @@ -0,0 +1,119 @@ +.. highlight:: cpp + +.. _lang-analogread: + +.. _lang-api-analogread: + +analogRead() +============ + +Used to perform ADC conversion. + +.. contents:: Contents + :local: + +Library Documentation +--------------------- + +.. doxygenfunction:: analogRead + +Discussion +---------- + +Reads the value from the specified analog pin. The Maple board +contains a 16-channel, 12-bit analog to digital converter. This means +that it will map input voltages between 0 and 3.3 volts into integer +values between 0 and 4095. This yields a resolution between readings +of 3.3V / 4096 units, or 0.8 millivolts. However, a number of factors +interfere with getting full accuracy and precision. For more +information, see :ref:`adc`. + +Before calling analogRead() on a pin, that pin must first be +configured for analog input, using :ref:`lang-pinMode` (you only +have to do this once, so it's usually done in :ref:`lang-setup`\ ). + +Parameter Discussion +-------------------- + +The pin parameter is the number of the analog input pin to read from. +Header pins on the Maple with ADC functionality (marked as "AIN" on +the silkscreen) are: + + 0, 1, 2, 3, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 27, 28 + +Note that pins 3, 27, and 28 are not marked AIN on the silkscreen +for Maple revisions through Rev 5, however, they **do work** as +analog input pins. + +Note +---- + +If the analog input pin is not connected to anything, the value +returned by analogRead() will fluctuate based on a number of factors +(e.g. the values of the other analog inputs, how close your hand is to +the board, etc.) in a seemingly random way. + + +Example +------- + + :: + + + int analogPin = 3; // potentiometer wiper (middle terminal) connected + // to analog pin 3. outside leads to ground and +3.3V + int val = 0; // variable to store the value read + + void setup() { + pinMode(analogPin, INPUT_ANALOG); // set up pin for analog input + SerialUSB.begin(); // set up usb virtual COM port + } + + void loop() { + val = analogRead(analogPin); // read the input pin + SerialUSB.println(val); // print the value, for debugging with + // a serial monitor + } + + +Arduino Compatibility +--------------------- + +The Arduino board contains a 6 channel (8 channels on the Mini and +Nano, 16 on the Mega), 10-bit analog to digital converter with an +input voltage range of 0V--5V. This means that it will map input +voltages between 0 and 5 volts (which is **larger** than Maple's range +of 0V-3.3V) into integer values between 0 and 1023 (which is +**smaller** than the Maple's range of 0--4095). + +This yields a theoretical resolution between readings of: 5 volts / +1024 units or .0049 volts (4.9 mV) per unit on Arduino boards, which +is larger, and thus less precise, than Maple's 0.0008 volts (0.8 mV). + +If your program expects Arduino-style 10-bit ADC, you can :ref:`right +shift <lang-bitshift>` the value of a Maple readout by 2, like so:: + + // right shift means that the result will be between 0 and 1023; + // be aware that you're losing a lot of precision if you do this + int adc_reading = analogRead(pin) >> 2; + +On the Arduino, the input range and resolution can be changed using +their implementation of `analogReference() +<http://arduino.cc/en/Reference/AnalogReference>`_\ . Because of the +way its hardware (as of Rev 5) was designed, it's not possible to +implement analogReference on the Maple, so this function doesn't +exist. If your inputs lie in a different voltage range than 0V--3.3V, +you'll need to bring them into that range before using analogRead. +Some basic tools to accomplish this are `resistor dividers +<http://en.wikipedia.org/wiki/Voltage_divider>`_ and `Zener diodes +<http://en.wikipedia.org/wiki/Voltage_source#Zener_voltage_source>`_\ +. However, opamps and other powered components can also be used if +greater precision is required. + +See also +-------- + +- :ref:`ADC note <adc>` +- `(Arduino) Tutorial: Analog Input Pins <http://arduino.cc/en/Tutorial/AnalogInputPins>`_ + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/analogwrite.rst b/docs/source/lang/api/analogwrite.rst new file mode 100644 index 0000000..9147b96 --- /dev/null +++ b/docs/source/lang/api/analogwrite.rst @@ -0,0 +1,173 @@ +.. highlight:: cpp + +.. _lang-analogwrite: + +.. _lang-api-analogwrite: + + +analogWrite() +============= + +.. note:: + + On the Maple, calling analogWrite() is the same as calling + :ref:`lang-pwmwrite`\ ; we recommend using that function directly + instead. + + This is because PWM is not true analog output (i.e., is not the + output of a `DAC + <http://en.wikipedia.org/wiki/Digital-to-analog_converter>`_\ ), so + the function is badly named. For instance, analogWrite() **has + absolutely nothing to do with** :ref:`lang-analogread`\ , which is + potentially confusing. + + The alias of analogWrite() to pwmWrite() is provided for the sake + of compatibility with Arduino only. + +.. contents:: Contents + :local: + +.. _lang-analogwrite-compatibility: + +Arduino Compatibility +--------------------- + +There are a few important differences between Arduino's `analogWrite() +<http://arduino.cc/en/Reference/AnalogWrite>`_ and Maple's +:ref:`lang-pwmwrite` that you should keep in mind. In each case, we +have some recommendations you can use to help converting from Arduino +to Maple. + +Difference 1: Duty cycle range is different +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The first and most important difference is that the largest possible +value for the duty cycle is much bigger on the Maple. Using Arduino's +analogWrite(), the duty cycle ranges between 0--255 (always off -- +always on)\ [#fbytemax]_\ . Using Maple's pwmWrite(), the duty cycle +ranges from 0--65,535 by default\ [#fuint16max]_\ . + +This is a good thing! The greater range of values on the Maple gives +you much more precise control over the duty cycle of your PWM output. + +If you're porting code from the Arduino and want a quick-and-dirty +fix, one solution is to :ref:`map <lang-map>` the argument to +analogWrite into the right range:: + + // Arduino code: + analogWrite(pin, duty); + + // Becomes Maple code: + analogWrite(pin, map(duty, 0, 255, 0, 65535)); + +This will convert values in the range 0-255 to values in the range +0--65,635, which is the correct default range for all of the timers +which control PWM output. See the :ref:`timers reference <timers>` +for more information. + +Another fix is to consult the :ref:`pin mapping mega table +<pin-mapping-mega-table>` to find the timer which controls PWM on the +pin you're using, then set that Timer's overflow to 255. Subsequent +calls to analogWrite() should work as on the Arduino (with the same +loss of precision). Note, however, that that affects the overflow for +the **entire timer**, so other code relying on that timer (such as any +:ref:`interrupts <lang-attachinterrupt>` the timer controls) will +likely need to be modified as well. + +Difference 2: You must use pinMode() to set up PWM +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The second difference is that on the Maple, you **must** set up the pin +for PWM output using :ref:`lang-pinmode`\ , with argument ``PWM``. +This should just be one extra line of code in your +:ref:`lang-setup` function. Example:: + + void setup() { + // set up pin 9 for PWM + pinMode(9, PWM); + } + +This also means that you can't later call :ref:`lang-digitalread` +or :ref:`lang-digitalwrite` on that pin (unless some time in +between, you use pinMode() to reconfigure that pin for ``INPUT`` or +``OUTPUT``; see the :ref:`lang-pinmode` page for more information). + +Difference 3: No PWM on pin 10 +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +On the Maple, the pins which support PWM are: 0, 1, 2, 3, 5, 6, 7, 8, +9, 11, 12, 14, 24, 27, and 28 or fifteen pins in total. That's *more* +PWM-capable pins as any Arduino board, but there are differences in +*which* pins support PWM. + +* On **most Arduino boards** (those with the ATmega168 or ATmega328; + this includes the **Arduino Uno**), this function works on pins 3, + 5, 6, 9, 10, and 11, or six pins total. Note that these boards + support PWM on pin 10, while Maple does not. + +* On the **Arduino Mega**, PWM works on pins 2 through 13, or twelve + pins total. Note that this board supports PWM on pins 4, 10, and + 13, while the Maple does not. + +* **Older Arduino boards** with an ATmega8 only support analogWrite() + on pins 9, 10, and 11. Maple does not support PWM on pin 10. + +In all cases, Arduino boards support PWM on pin 10, unlike Maple. We +did our best to make PWM as pin-compatible as possible; however, +circuit layout constraints prevented us from achieving perfect +compatibility. + +The "safest" pins to use for PWM output are pins 9 and 11. These pins +work on any Arduino board and on Maple. The "safe" pins, which work +on most recent Arduino boards, the Arduino Mega and the Maple, are +pins 3, 5, 6, 9, and 11. Thus, if you want your project to be as +portable as possible between Maple and Arduino, we recommend using the +"safest" pins first, then the "safe" pins, then any other pins, as +necessary. + +Difference 4: PWM frequency +^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The frequency of the PWM signal (i.e., the frequency of a complete +on/off cycle) on the Arduino is approximately 490 Hz. + +On the Maple, the frequency is configurable, defaulting to about 1100 +Hz, or 1.1 KHz. This is because the PWM frequency is the frequency of +the timer which controls PWM output on the particular pin (\ +:ref:`the PWM tutorial has the details <pwm>`\ ). + +If your application definitely requires Arduino's PWM frequency, then +the steps are: + +1. Figure out which :ref:`timer <lang-hardwaretimer>` controls PWM + output on your pin (\ :ref:`this table <pwm-timer-table>` is your + friend here). Let's say it's ``Timern``\ , where ``n`` is some + number 1, 2, 3, or 4. + +2. Call ``Timern.setPeriod(2041)``\ . This will set the timer's + period to approximately 2041 microseconds, which is a frequency of + approximately 490 Hz. + +Be aware that this will change the period for the **entire timer**\ , +and will affect anything else in your program that depends on that +timer. The important examples are :ref:`timer interrupts +<lang-hardwaretimer-attachinterrupt>` and :ref:`PWM +<timers-pwm-conflicts>`\ . + +See also +-------- + +- :ref:`Maple PWM tutorial <pwm>` + +.. rubric:: Footnotes + +.. [#fbytemax] This is because the value for the duty cycle on Arduino + must fit in 1 byte of memory, and an unsigned (i.e., nonnegative) + integer with size 1 byte can hold the values between 0 and 255. + +.. [#fuint16max] This is because the value for the duty cycle on the + Maple uses 2 bytes of memory, and an unsigned (i.e., nonnegative) + integer with size 2 bytes can hold the values between 0 and 65,535. + + +.. include:: cc-attribution.txt diff --git a/docs/source/arduino/attachinterrupt.rst b/docs/source/lang/api/attachinterrupt.rst index 189141b..0b8907f 100644 --- a/docs/source/arduino/attachinterrupt.rst +++ b/docs/source/lang/api/attachinterrupt.rst @@ -1,9 +1,19 @@ .. highlight:: cpp -.. _arduino-attachinterrupt: +.. _lang-attachinterrupt: -attachInterrupt(interrupt, function, mode) -========================================== +attachInterrupt() +================= + +Used to specify a function to call when an external interrupt (like an +GPIO changing from LOW to HIGH, a button getting pressed, etc.) +occurs. + +.. contents:: Contents + :local: + +Library Documentation +--------------------- .. doxygenfunction:: attachInterrupt @@ -14,17 +24,15 @@ attachInterrupt(interrupt, function, mode) Discussion ---------- -Specifies a function to call when an external interrupt occurs. -Replaces any previous function that was attached to the interrupt. -For more information on external interrupts on the Maple +Because the function will run in interrupt context, inside of it, +:ref:`lang-delay` won't work, and the value returned by +:ref:`lang-millis` will not increment. Serial data received while +in the function may be lost. You should declare as ``volatile`` any +global variables that you modify within the attached function. -Note ----- - -Inside the attached function, delay() won't work, and the value -returned by millis() will not increment. Serial data received while in -the function may be lost. You should declare as volatile any variables -that you modify within the attached function. +There are a few constraints you should be aware of if you're using +more than one interrupt at a time; the :ref:`external-interrupts` page +has the details. Using Interrupts @@ -33,8 +41,7 @@ Using Interrupts Interrupts are useful for making things happen automatically in microcontroller programs, and can help solve timing problems. A good task for using an interrupt might be reading a rotary encoder, -monitoring user input. - +or monitoring user input. If you wanted to insure that a program always caught the pulses @@ -49,45 +56,47 @@ situations, using an interrupt can free the microcontroller to get some other work done while not missing the doorbell. - Example ------- :: int maple_led_pin = 13; - volatile int state = LOW; - - void setup() - { + volatile int state = LOW; // must declare volatile, since it's + // modified within the blink handler + + void setup() { pinMode(maple_led_pin, OUTPUT); attachInterrupt(0, blink, CHANGE); } - - void loop() - { + + void loop() { digitalWrite(maple_led_pin, state); } - - void blink() - { + + void blink() { state = !state; } -Arduino Compatibility Note --------------------------- +Arduino Compatibility +--------------------- Most Arduino boards have two external interrupts: numbers 0 (on digital pin 2) and 1 (on digital pin 3). The Arduino Mega has an additional four: numbers 2 (pin 21), 3 (pin 20), 4 (pin 19), and 5 -(pin 18). +(pin 18). On the Maple, you don't have to remember which interrupt +number goes with which pin -- just tell ``attachInterrupt()`` the pin +you want. See also -------- -- `detachInterrupt <http://arduino.cc/en/Reference/DetachInterrupt>`_ +- :ref:`detachInterrupt <lang-detachinterrupt>` +- :ref:`external-interrupts` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/bit.rst b/docs/source/lang/api/bit.rst new file mode 100644 index 0000000..dd5c050 --- /dev/null +++ b/docs/source/lang/api/bit.rst @@ -0,0 +1,44 @@ +.. _lang-bit: + +bit() +===== + +(Macro) Computes the value of an (unsigned) integer with the specified +bit set (``bit(0)`` is 1, ``bit(1)`` is 2, ``bit(2)`` is 4, then 8, +16, 32, etc.). + +Syntax +------ + +``bit(n)`` + + +Parameters +---------- + +* **n** the bit to set. + + +Value +----- + +The value of an integer with the given bit set. + + +Arduino Compatibility +--------------------- + +The Maple implementation of bit is compatible with Arduino. + + +See also +-------- + + +- :ref:`lang-bitread` +- :ref:`lang-bitwrite` +- :ref:`lang-bitset` +- :ref:`lang-bitclear` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/bitclear.rst b/docs/source/lang/api/bitclear.rst new file mode 100644 index 0000000..941f912 --- /dev/null +++ b/docs/source/lang/api/bitclear.rst @@ -0,0 +1,44 @@ +.. _lang-bitclear: + +bitClear() +========== + +(Macro) Clears (writes a 0 to) a bit of a numeric variable. + +Syntax +------ + +``bitClear(x, n)`` + + +Parameters +---------- + +* **x** the numeric variable whose bit to clear + +* **n** which bit to clear, starting at 0 for the least-significant + (rightmost) bit + + +Returns +------- + +None. + + +Arduino Compatibility +--------------------- + +This implementation is compatible with that of Arduino. + + +See also +-------- + +- :ref:`bit <lang-bit>`\ () +- :ref:`bitRead <lang-bitread>`\ () +- :ref:`bitWrite <lang-bitwrite>`\ () +- :ref:`bitSet <lang-bitset>`\ () + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/bitread.rst b/docs/source/lang/api/bitread.rst new file mode 100644 index 0000000..46b4478 --- /dev/null +++ b/docs/source/lang/api/bitread.rst @@ -0,0 +1,46 @@ +.. _lang-bitread: + +bitRead() +========= + +(Macro) Gets the value of a bit in a number. + + +Syntax +------ + +``bitRead(x, n)`` + + +Parameters +---------- + +* **x** the number from which to read the bit. + +* **n** which bit to read, starting at 0 for the least-significant + (rightmost) bit + + +Value +----- + +The value of the bit (0 or 1). + + +Arduino Compatibility +--------------------- + +The Maple implementation of ``bitRead`` is compatible with Arduino. + + +See also +-------- + + +- :ref:`lang-bit` +- :ref:`lang-bitwrite` +- :ref:`lang-bitset` +- :ref:`lang-bitclear` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/bitset.rst b/docs/source/lang/api/bitset.rst new file mode 100644 index 0000000..ccd76de --- /dev/null +++ b/docs/source/lang/api/bitset.rst @@ -0,0 +1,46 @@ +.. _lang-bitset: + +bitSet() +======== + +(Macro) Sets (writes a 1 to) a bit of a numeric variable. + + +Syntax +------ + +``bitSet(x, n)`` + + +Parameters +---------- + +* **x** the numeric variable whose bit to set + +* **n** which bit to set, starting at 0 for the least-significant + (rightmost) bit + + +Value +----- + +None. + + +Arduino Compatibility +--------------------- + +The Maple implementation of bitSet is compatible with Arduino. + + +See Also +-------- + +- :ref:`lang-bit` +- :ref:`lang-bitread` +- :ref:`lang-bitwrite` +- :ref:`lang-bitclear` + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/bitwrite.rst b/docs/source/lang/api/bitwrite.rst new file mode 100644 index 0000000..b3feff2 --- /dev/null +++ b/docs/source/lang/api/bitwrite.rst @@ -0,0 +1,46 @@ +.. highlight:: cpp + +.. _lang-bitwrite: + +bitWrite() +========== + +(Macro) Writes a bit of a numeric variable. + +Syntax +------ + +:: + + bitWrite(x, n, b) + +Parameters +---------- + +**x**: the numeric variable whose bit to write. + +**n**: which bit of the number to write, starting at 0 for the +least-significant (rightmost) bit. + +**b**: the value to write to the bit (0 or 1). + +Returns +------- + +Nothing. + +Arduino Compatibility +--------------------- + +Maple's version of ``bitWrite()`` is compatible with Arduino. + +See also +-------- + +- :ref:`bit() <lang-bit>` +- :ref:`bitRead() <lang-bitRead>` +- :ref:`bitSet() <lang-bitSet>` +- :ref:`bitClear() <lang-bitClear>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/cc-attribution.txt b/docs/source/lang/api/cc-attribution.txt new file mode 100644 index 0000000..e100140 --- /dev/null +++ b/docs/source/lang/api/cc-attribution.txt @@ -0,0 +1,9 @@ +.. Included in all this directory's files in order to satisfy the +.. Arduino CC Attribution-ShareAlike 3.0 License + +.. admonition:: License and Attribution + + This documentation page was adapted from the `Arduino Reference + Documentation <http://arduino.cc/en/Reference/HomePage>`_\ , which + is released under a `Creative Commons Attribution-ShareAlike 3.0 + License <http://creativecommons.org/licenses/by-sa/3.0/>`_. diff --git a/docs/source/lang/api/constants.rst b/docs/source/lang/api/constants.rst new file mode 100644 index 0000000..4426293 --- /dev/null +++ b/docs/source/lang/api/constants.rst @@ -0,0 +1,327 @@ +.. _lang-constants: + +Constants +========= + +Constants are like predefined variables, whose values can't +change. They are used to make the programs easier to read and modify. +This page describes the most commonly used constants. + +.. contents:: Contents + :local: + +.. _lang-constants-bool: + +Boolean Constants +----------------- + +There are two constants used to represent truth and falsity: ``true``, +and ``false``. + +.. _lang-constants-false: + +false +^^^^^ + +``false`` is the false ``bool`` value. An integer which is 0 evaluates +to ``false`` as a boolean. + +.. _lang-constants-true: + +true +^^^^ + +``true`` is the true ``bool`` value. As an integer, ``true`` is often +said to be 1. This is correct in the sense that ``true`` evaluates to +1 as an integer. However, any integer which is *non-zero* is ``true`` +as a :ref:`bool <lang-booleanvariables>`. So -1, 2 and -200 are all +"true", in the sense that these numbers are treated the same as +``true`` in a boolean context. + +Note that the ``true`` and ``false`` constants are typed in lowercase; +unlike e.g. ``HIGH``, ``LOW``, ``INPUT``, and ``OUTPUT`` (which are +described below). + + +Pin Levels: HIGH and LOW +------------------------ + +When reading or writing to a digital pin there are only two possible +values a pin can be set to: ``HIGH`` and ``LOW``. + +.. _lang-constants-high: + +HIGH +^^^^ + +The meaning of ``HIGH`` (in reference to a pin) is somewhat different +depending on whether the pin is set to ``INPUT`` or ``OUTPUT``. When a +pin is configured as an ``INPUT`` (using :ref:`pinMode() +<lang-pinmode>`), and read with :ref:`digitalRead() +<lang-digitalread>`, the microcontroller will report ``HIGH`` if a +voltage of 3 volts or more is present at the pin. + +.. TODO? Following seems false; check it out sometime, leave out for now: + +.. A pin may also be configured as an ``INPUT`` with ``pinMode()``, and +.. subsequently made ``HIGH`` with :ref:`digitalWrite() +.. <lang-digitalwrite>`, this will set the internal pullup resistors, +.. which will *steer* the input pin to a HIGH reading unless it is pulled +.. LOW by external circuitry. + +When a pin is configured to ``OUTPUT`` with pinMode, and set to +``HIGH`` with :ref:`digitalWrite() <lang-digitalwrite>`, the pin is at +3.3 volts. In this state it can *source* current, e.g. light an LED +that is connected through a series resistor to ground, or to another +pin configured as an output and set to ``LOW``. + +.. _lang-constants-low: + +LOW +^^^ + +The meaning of ``LOW`` also has a different meaning depending on +whether a pin is set to ``INPUT`` or ``OUTPUT``. When a pin is +configured as an ``INPUT`` with :ref:`pinMode() <lang-pinmode>`, and +read with :ref:`digitalRead() <lang-digitalread>`, the microcontroller +will report ``LOW`` if a voltage of 2 volts or less is present at the +pin. + +When a pin is configured to ``OUTPUT`` with ``pinMode()``, and set to +``LOW`` with :ref:`digitalWrite() <lang-digitalwrite>`, the +microcontroller will attempt to keep that pin's voltage at 0V. In this +state it can *sink* current, e.g. light an LED that is connected +through a series resistor to +3.3V, or to another pin configured as an +output, and set to ``HIGH``. + +Pin Modes +--------- + +Digital pins can be used in a variety of modes. The basic modes, +``INPUT`` and ``OUTPUT``, have been introduced above. Changing a pin +from ``INPUT`` TO ``OUTPUT`` with :ref:`pinMode() <lang-pinmode>` +drastically changes the electrical behavior of the pin. + +This section describes the basic digital pin modes (``INPUT`` and +``OUTPUT``) only. For a detailed description of all possible pin +modes, see the :ref:`pinMode() <lang-pinmode>` reference page. + +.. _lang-constants-input: + +INPUT +^^^^^ + +Maple (STM32) pins configured as ``INPUT`` are said to be in a +high-impedance state. One way of explaining this is that pins +configured as ``INPUT`` make extremely small demands on the circuit +that they are sampling. This makes them useful for reading a sensor, +but not powering an LED. + +.. _lang-constants-output: + +OUTPUT +^^^^^^ + +Pins configured as ``OUTPUT`` with :ref:`pinMode() <lang-pinmode>` are +said to be in a low-impedance state. This means that they can provide +a substantial amount of current to other circuits. STM32 pins can +source (provide positive current) or sink (provide negative current) +up to 50 mA (milliamps) of current to other devices/circuits. This +makes them useful for powering LEDs, but useless for reading sensors. + +Pins configured as outputs can also be damaged or destroyed if short +circuited to either ground or 3.3V power rails. The amount of current +provided by an STM32 pin is also not enough to power most relays or +motors, and some interface circuitry will be required. + +.. _lang-constants-integers: + +Integer Constants +----------------- + +Integer constants (or more properly speaking, integer *literals*) are +numbers used directly in a sketch, like ``123``. By default, an +integer literal is treated as a (signed) :ref:`int <lang-int>`, but +you can change this with the U and L modifiers (see :ref:`below +<lang-constants-integers-u-l>`). You can specify negative numbers by +putting a minus sign in front, like ``-123``. + +Normally, integer literals are treated as base 10 (decimal) integers, +but special notation (formatters) may be used to enter numbers in +other bases. These are summarized in the following table: + +.. list-table:: + :header-rows: 1 + + * - Base + - Example + - Formatter + - Comment + + * - 10 (decimal) + - ``123`` + - None + - + + * - 2 (binary) + - ``0b1111011`` + - Leading "0b" + - GCC extension; not standard C++ + + * - 8 (octal) + - ``0173`` + - Leading "0" + - Characters 0-7 valid + + * - 16 (hexadecimal) + - ``0x7B`` + - Leading "0x" + - Characters 0-9, A-F (or a-f) valid + +Binary constants (like ``B1111011``) for values between 0 and 255 are +supported for compatibility with Arduino only. Their use in new +programs is discouraged. + +.. _lang-constants-integers-dec: + +**Decimal** is base 10. This is the common number system we learn in +school. Integer literals without other prefixes are assumed to be in +decimal format. + +For example, the decimal literal ``101`` is one hundred and one: 1×10\ +:sup:`2` + 0×10\ :sup:`1` + 1×10\ :sup:`0` = 101. + +.. _lang-constants-integers-bin: + +**Binary** is base two. Only characters 0 and 1 are valid. Binary +literals are indicated by the prefix ``0b`` (this is a :ref:`GCC +<arm-gcc>` extension; it's not standard C++). + +For example, the binary literal ``0b101`` is five: 1×2\ :sup:`2` + +0×2\ :sup:`1` + 1×2\ :sup:`0` = 5. + +.. _lang-constants-integers-oct: + +**Octal** is base eight. Only characters 0 through 7 are valid. Octal +literals are indicated by the prefix ``0``. + +For example, the octal literal ``0101`` is sixty five: 1×8\ :sup:`2` + +0×8\ :sup:`1` + 1×8\ :sup:`0` = 65. + +.. warning:: Bugs sometimes result by (unintentionally) including a + leading "0" before an integer literal, which makes the compiler + interpret it in octal. + +.. _lang-constants-integers-hex: + +**Hexadecimal** (or "hex") is base sixteen. Valid characters are 0 +through 9 and letters A through F; A has the value 10, B is 11, up to +F, which is 15. Hex values are indicated by the prefix ``0x``. A-F +may be typed in upper or lower case (a-f). + +For example, the hexadecimal literal ``0x101`` is two hundred fifty +seven: 1×16\ :sup:`2` + 0×16\ :sup:`1` + 1×16\ :sup:`0` = 257. + +The hexadecimal literal ``0xCF2`` is three thousand, three hundred +fourteen: 12×16\ :sup:`2` + 15×16\ :sup:`1` + 2×16\ :sup:`0` = 3314. + +(Remember that in hex, ``A`` means 10, and counting up, ``B``\ =11, so +``C``\ =12 and ``F``\ =15). + +.. _lang-constants-integers-u-l: + +U and L Suffixes +^^^^^^^^^^^^^^^^ + +By default, an integer constant is treated as an :ref:`int +<lang-int>`, with the attendant :ref:`limitations in values +<lang-int-overflow>`. To specify an integer constant with another data +type, follow it with: + +- a ``u`` or ``U`` to interpret the constant as an unsigned value. + For example, ``33U`` is an :ref:`unsigned int <lang-unsignedint>`. + +- an ``l`` or ``L`` to interpret the constant as a long value. For + example, ``100000L`` is a :ref:`long <lang-long>`. + +- a ``ul`` or ``UL`` to do both. For example, ``32767UL`` is an + :ref:`unsigned long <lang-unsignedlong>`. + +.. _lang-constants-fp: + +Floating-Point Constants +------------------------ + +Similar to integer literals, floating point constants (properly: +floating-point *literals*) are used to make code more readable. +Floating point literals are swapped at compile time for the value to +which the expression evaluates. + +A floating point literal is any number which includes a decimal point. +For instance, ``3.0`` is a floating-point literal for the number 3. +By default, a floating-point literal is a :ref:`double <lang-double>`. +In order for the literal to be interpreted as a :ref:`float +<lang-float>`, you can write ``f`` directly after it. For example, +``3.0f`` is a floating-point literal with type ``float``. + +Floating point constants can also be expressed in a variety of +scientific notation. ``E`` and ``e`` are both accepted as valid +exponent indicators. Some examples are given in the following table: + + +.. list-table:: + :header-rows: 1 + + * - Floating-point literal + - Evaluates to + - Alternate expression + + * - ``10.0`` + - 10 + - + + * - ``2.34E5`` + - 2.34×10\ :sup:`5` + - ``234000.0`` + + * - ``67e-12`` + - 67.0×10\ :sup:`-12` + - ``0.000000000067`` + +.. _lang-constants-board: + +Board-Specific Constants +------------------------ + +This section documents constants whose value might change across +different LeafLabs boards. You can use these constants to help ensure +that your code will be portable across different boards. + +.. TODO replace "upcoming" when Mini, Native come out + +.. _lang-constants-led: + +- ``BOARD_LED_PIN``: the number of the pin which connects to the + built-in LED. On the Maple, this is pin 13, but it's not guaranteed + to be the same in upcoming boards like the Maple Mini. + +.. _lang-constants-but: + +- ``BOARD_BUTTON_PIN``: the number of the pin which connects to the + built-in button (labeled "BUT"). On the Maple, this is pin 38, but + it's not guaranteed to be the same in other boards. + +See Also +-------- + +- :ref:`pinMode() <lang-pinmode>` +- :ref:`Boolean Variables <lang-booleanvariables>` +- :ref:`#define <lang-define>` +- :ref:`int <lang-int>` +- :ref:`unsigned int <lang-unsignedint>` +- :ref:`long <lang-long>` +- :ref:`unsigned long <lang-unsignedlong>` +- :ref:`float <lang-float>` +- :ref:`double <lang-double>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/constrain.rst b/docs/source/lang/api/constrain.rst new file mode 100644 index 0000000..d19b61c --- /dev/null +++ b/docs/source/lang/api/constrain.rst @@ -0,0 +1,69 @@ +.. highlight:: cpp + +.. _lang-constrain: + +constrain() +=========== + +(Macro) Constrains a number to be within a range. + +Syntax +------ + +:: + + constrain(x, a, b) + + +Parameters +---------- + +**x**: the number to constrain + +**a**: the lower end of the range + +**b**: the upper end of the range + +Returns +------- + +**x**: if **x** is between **a** and **b** + +**a**: if **x** is less than **a** + +**b**: if **x** is greater than **b** + +Example +------- + +:: + + // limits range of sensor values to between 10 and 150: + sensVal = constrain(sensVal, 10, 150); + + +Warning +------- + +Because of the way ``constrain()`` is implemented, avoid using other +functions or causing side effects inside the parentheses, as it may +lead to incorrect results:: + + constrain(x,a++,b); // avoid this - yields incorrect results + + constrain(x,a,b); // use this instead- + a++; // keep other math outside constrain() + +Arduino Compatibility +--------------------- + +Maple's implementation of ``constrain()`` is compatible with Arduino. + +See also +-------- + +- :ref:`min() <lang-min>` +- :ref:`max() <lang-max>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/cos.rst b/docs/source/lang/api/cos.rst new file mode 100644 index 0000000..3fbb0af --- /dev/null +++ b/docs/source/lang/api/cos.rst @@ -0,0 +1,32 @@ +.. _lang-cos: + +cos() +===== + +Calculates the cosine of an angle. + +Library Documentation +--------------------- + +.. doxygenfunction:: cos + +Arduino Compatibility +--------------------- + +The Maple ``cos()`` implementation is compatible with Arduino. + +Note that the Maple implementation comes from `newlib +<http://sourceware.org/newlib/>`_\ , while Arduino's is that of +`avr-libc <http://avr-libc.nongnu.org/>`_\ . + +See also +-------- + + +- :ref:`sin() <lang-sin>` +- :ref:`tan() <lang-tan>` +- :ref:`float <lang-float>` +- :ref:`double <lang-double>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/delay.rst b/docs/source/lang/api/delay.rst new file mode 100644 index 0000000..90ca268 --- /dev/null +++ b/docs/source/lang/api/delay.rst @@ -0,0 +1,72 @@ +.. highlight:: cpp + +.. _lang-delay: + +delay() +======= + +Pauses the program for at least a given number of milliseconds. (There +are 1000 milliseconds in a second.) + +Library Documentation +--------------------- + +.. doxygenfunction:: delay + + +Discussion +---------- + +While it is easy to create a blinking LED with the ``delay()`` +function, and many sketches use short delays for such tasks as switch +debouncing, the use of ``delay()`` in a sketch has significant +drawbacks. No other reading of sensors, mathematical calculations, or +pin manipulation can go on during the delay function, so in effect, it +brings most other activity to a halt. For alternative approaches to +controlling timing see the :ref:`millis() <lang-millis>` function +and the "Blink Without Delay" sketch cited :ref:`below +<lang-delay-seealso>`\ . More knowledgeable programmers usually +avoid the use of ``delay()`` for timing of events longer than tens of +milliseconds, unless the sketch is very simple. + +Certain things *do* go on while the ``delay()`` function is +controlling the STM32 chip, however, because the delay function does +not disable interrupts. Serial communication that appears at the RX +pin is recorded, PWM (see :ref:`pwmWrite() <lang-pwmwrite>`\ ) values +and pin states are maintained, and :ref:`interrupts +<lang-attachinterrupt>` will work as they should. + + +Example +------- + +:: + + int ledPin = 13; // LED connected to pin 13 + + void setup() { + pinMode(ledPin, OUTPUT); // sets the digital pin as output + } + + void loop() { + digitalWrite(ledPin, HIGH); // sets the LED on + delay(1000); // waits for a second + digitalWrite(ledPin, LOW); // sets the LED off + delay(1000); // waits for a second + } + +.. _lang-delay-seealso: + +See also +-------- + + +- :ref:`millis() <lang-millis>` +- :ref:`micros() <lang-micros>` +- :ref:`delayMicroseconds() <lang-delayMicroseconds>` +- (Arduino) `Blink Without Delay + <http://arduino.cc/en/Tutorial/BlinkWithoutDelay>`_ example (works + unmodified on Maple) + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/delaymicroseconds.rst b/docs/source/lang/api/delaymicroseconds.rst new file mode 100644 index 0000000..24a8286 --- /dev/null +++ b/docs/source/lang/api/delaymicroseconds.rst @@ -0,0 +1,65 @@ +.. highlight:: cpp + +.. _lang-delaymicroseconds: + +delayMicroseconds() +=================== + +Pauses the program for the amount of time (in microseconds) +specified as parameter. There are a thousand microseconds in a +millisecond, and a million microseconds in a second. + +Library Documentation +--------------------- + +.. doxygenfunction:: delayMicroseconds + + +Example +------- + +The following example configures pin number 8 to work as an output +pin, and sends a train of pulses with a period of roughly 100 +microseconds:: + + int outPin = 8; + + void setup() { + pinMode(outPin, OUTPUT); // sets the digital pin as output + } + + void loop() { + digitalWrite(outPin, HIGH); // sets the pin on + delayMicroseconds(50); // pauses for 50 microseconds + digitalWrite(outPin, LOW); // sets the pin off + delayMicroseconds(50); // pauses for 50 microseconds + } + + +Caveats and Known Issues +------------------------ + +The longest time ``delayMicroseconds()`` can delay is bounded by its +argument type and the STM32 clock rate to be (2^32 - 1) / 12 +microseconds, or less than 6 minutes. For longer pauses, use of +:ref:`lang-delay` is possible. + +Arduino Compatibility +--------------------- + +While we have made every effort we could to ensure that the timing of +delayMicroseconds is as accurate as possible, we cannot guarantee it +will behave as the Arduino implementation down to the microsecond, +especially for smaller values of ``us``. + +See Also +-------- + +- :ref:`millis <lang-millis>` +- :ref:`micros <lang-micros>` +- :ref:`delay <lang-delay>` + + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/detachinterrupt.rst b/docs/source/lang/api/detachinterrupt.rst new file mode 100644 index 0000000..adb2439 --- /dev/null +++ b/docs/source/lang/api/detachinterrupt.rst @@ -0,0 +1,37 @@ +.. _lang-detachinterrupt: + +detachInterrupt() +================= + +Used to disable an interrupt specified with +:ref:`lang-attachinterrupt`\ . + + +Library Documentation +--------------------- + +.. doxygenfunction:: detachInterrupt + +Arduino Compatibility +--------------------- + +There is one important difference between the Maple version of +detachInterrupt and the Arduino version. On the Maple, the argument +to ``detachInterrupt()`` is the *pin* on which the interrupt is +attached, while on the Arduino, the argument is the *interrupt +number*, which is different from the pin the interrupt is enabled on. + +If you're calling this function, you've already called +:ref:`lang-attachinterrupt` to set up your interrupt handler, so +just call ``detachInterrupt()`` with the same pin argument you gave to +``attachInterrupt()``. + +See Also +-------- + +- :ref:`attachInterrupt() <lang-attachInterrupt>` + + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/digitalread.rst b/docs/source/lang/api/digitalread.rst new file mode 100644 index 0000000..3502587 --- /dev/null +++ b/docs/source/lang/api/digitalread.rst @@ -0,0 +1,58 @@ +.. highlight:: cpp + +.. _lang-digitalread: + +digitalRead() +============= + +Reads the value from a specified digital pin, either :ref:`HIGH +<lang-constants-high>` or :ref:`LOW <lang-constants-low>`. + + +Library Documentation +--------------------- + +.. doxygenfunction:: digitalRead + + +Example +------- + +The following example turns the LED on when the button is pressed:: + + int ledPin = 13; // LED connected to Maple pin 13 + int buttonPin = 38; // BUT connected to Maple pin 38 + + void setup() { + pinMode(ledPin, OUTPUT); + pinMode(buttonPin, INPUT); + } + + void loop() { + int val = digitalRead(buttonPin); // reads the input pin + digitalWrite(ledPin, val); + } + +Note +---- + +If the pin isn't connected to anything, ``digitalRead()`` can return +either HIGH or LOW (and this can change in a way that seems random). + +Arduino Compatibility +--------------------- + +The Maple version of ``digitalRead()`` is compatible with Arduino. + + +See Also +-------- + +- :ref:`pinMode <lang-pinMode>` +- :ref:`digitalWrite <lang-digitalWrite>` + + + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/digitalwrite.rst b/docs/source/lang/api/digitalwrite.rst new file mode 100644 index 0000000..6124d5f --- /dev/null +++ b/docs/source/lang/api/digitalwrite.rst @@ -0,0 +1,68 @@ +.. highlight:: cpp + +.. _lang-digitalwrite: + +digitalWrite() +============== + +Write a :ref:`HIGH <lang-constants-high>` or a :ref:`LOW +<lang-constants-low>` value to a pin configured as :ref:`OUTPUT +<lang-constants-output>`. + +Library Documentation +--------------------- + +.. doxygenfunction:: digitalWrite + +Discussion +---------- + +If the pin has been configured as an ``OUTPUT`` with :ref:`pinMode() +<lang-pinmode>` its voltage will be set to the corresponding value: +3.3V for ``HIGH``, and 0V (ground) for ``LOW``. + +.. TODO make the following paragraphs true, but refer the reader to +.. INPUT_PULLUP and INPUT_PULLDOWN: + +If the pin is configured as an ``INPUT``, writing a ``HIGH`` value +with ``digitalWrite()`` will enable an internal pullup resistor. +Writing ``LOW`` will disable the pullup. The pullup resistor is enough +to light an LED dimly, so if LEDs appear to work, but very dimly, this +is a likely cause. The remedy is to set the pin to an output with the +:ref:`pinMode() <lang-pinmode>` function. + +.. note:: Pin 13 is harder to use as an input than the other pins + because it has an LED and resistor soldered to it in series. If you + enable its internal pull-up resistor, it will likely hang at around + 1.1V instead of the expected 3.3V because the onboard LED and + series resistor pull the voltage level down. If you must use pin 13 + as a digital input, use an external pull-down resistor. + +Example +------- + +The following example sets pin 13 to ``HIGH``, makes a one-second-long +delay, sets the pin back to ``LOW``, and delays again, causing a +blinking pattern:: + + + int ledPin = 13; // LED connected to digital pin 13 + + void setup() { + pinMode(ledPin, OUTPUT); // sets the digital pin as output + } + + void loop() { + digitalWrite(ledPin, HIGH); // sets the LED on + delay(1000); // waits for a second + digitalWrite(ledPin, LOW); // sets the LED off + delay(1000); // waits for a second + } + +See Also +-------- + +- :ref:`pinMode <lang-pinmode>` +- :ref:`digitalRead <lang-digitalread>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/hardwarespi.rst b/docs/source/lang/api/hardwarespi.rst new file mode 100644 index 0000000..c71b2c3 --- /dev/null +++ b/docs/source/lang/api/hardwarespi.rst @@ -0,0 +1,152 @@ +.. highlight:: cpp + +.. _lang-hardwarespi: + +HardwareSPI +=========== + +This class is used for creating objects to manage the Maple's built-in +SPI ports. The Maple has two SPI ports. The relevant pins +corresponding to each port's logic signals are documented in the +following table (and on the Maple silkscreen): + +.. _lang-hardwarespi-pinout: + +.. list-table:: + :header-rows: 1 + + * - Port number + - NSS + - MOSI + - MISO + - SCK + + * - 1 + - 10 + - 11 + - 12 + - 13 + + * - 2 + - 31 + - 32 + - 33 + - 34 + +If you use a SPI port, you cannot simultaneously use its associated +pins for other purposes. + +Library Documentation +--------------------- + +HardwareSPI Class Reference +^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +You can use the SPI interface by including a declaration ``HardwareSPI +Spi(number);`` at the start of the sketch or program. The ``number`` +must be either 1 or 2 and specifies which port to use. Once this is +done, you can call any of the methods documented here using +``Spi.method(arguments)``; for example, ``Spi.send(0x13)`` would send +the value ``0x13`` into the port buffer to be transmitted as soon as +possible. + +.. cpp:class:: HardwareSPI + + Class for interacting with SPI. + +.. cpp:function:: HardwareSPI::HardwareSPI(uint32 spi_num) + + Construct an object for managing a SPI peripheral. ``spi_num`` + must be 1 or 2; see the :ref:`table above + <lang-hardwarespi-pinout>` for pinout information. + +.. cpp:function:: void HardwareSPI::begin(SPIFrequency freq, uint32 endianness, uint32 mode) + + Configure the baudrate of the given SPI port and set up the header + pins appropriately. + + Parameters: + + - ``freq``: one of the ``SPIFrequency`` values, given :ref:`below + <lang-hardwarespi-spifrequency>`. + + - ``endianness``: either ``LSBFIRST`` (little-endian) or + ``MSBFIRST`` (big-endian). + + - ``mode``: one of 0, 1, 2, or 3, and specifies which SPI mode is + used. The mode number determines a combination of polarity and + phase according to the following table: + + .. list-table:: + :header-rows: 1 + + * - Mode + - Polarity + - Phase + + * - 0 + - 0 + - 0 + + * - 1 + - 0 + - 1 + + * - 2 + - 1 + - 0 + + * - 3 + - 1 + - 1 + + For more information on polarity and phase, see the + :ref:`external references, below <lang-hardwarespi-seealso>`. + +.. cpp:function:: void HardwareSPI::begin() + + A convenience ``begin()``, equivalent to ``begin(SPI_1_125MHZ, + MSBFIRST, 0)``. + +.. cpp:function:: uint8 HardwareSpi::send(uint8 *data, uint32 length) + + Writes ``data`` into the port buffer to be transmitted as soon as + possible, where ``length`` is the number of bytes to send from + ``data``. Returns the last byte shifted back from slave. + +.. cpp:function:: uint8 HardwareSpi::send(uint8 data) + + Writes the single byte ``data`` into the port buffer to be + transmitted as soon as possible. Returns the data byte shifted + back from the slave. + +.. cpp:function:: uint8 HardwareSpi::recv() + + Reads a byte from the peripheral. Returns the next byte in the + buffer. + +SPI Speeds +^^^^^^^^^^ + +.. _lang-hardwarespi-spifrequency: + +The possible SPI speeds are configured using the ``SPIFrequency`` enum: + +.. doxygenenum:: SPIFrequency + +.. _lang-hardwarespi-seealso: + +See Also +-------- + +* `Wikipedia Article on Serial Peripheral Interface Bus (SPI) + <http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus>`_ +* `Arduino reference on SPI + <http://www.arduino.cc/playground/Code/Spi>`_ +* `Hardcore SPI on Arduino <http://klk64.com/arduino-spi/>`_ by kik64 +* STMicro documentation for STM32F103RB microcontroller: + + * `Datasheet <http://www.st.com/stonline/products/literature/ds/13587.pdf>`_ (pdf) + * `Reference Manual <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (pdf) + + diff --git a/docs/source/lang/api/hardwaretimer.rst b/docs/source/lang/api/hardwaretimer.rst new file mode 100644 index 0000000..258471b --- /dev/null +++ b/docs/source/lang/api/hardwaretimer.rst @@ -0,0 +1,368 @@ +.. highlight:: cpp + +.. _lang-hardwaretimer: + +HardwareTimer +============= + +This class defines the public API for interfacing with the STM32's +built-in timer peripherals. More information on these peripherals +(including code examples) is available in the :ref:`timers reference +<timers>`. + +Library Documentation +--------------------- + +HardwareTimer Class Reference +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +To interact with a particular timer, call one of the methods +documented below on one of the predefined ``HardwareTimer`` instances. +For example, to set the prescale factor on timer 1 to 5, call +``Timer1.setPrescaleFactor(5)``. + +.. cpp:class:: HardwareTimer + + Class for interacting with a timer. There are four predefined + instances available on the Maple: ``Timer1``, ``Timer2``, + ``Timer3``, and ``Timer4``. + +.. _lang-hardwaretimer-attachinterrupt: + +.. cpp:function:: void HardwareTimer::attachInterrupt(int channel, voidFuncPtr handler) + + Attach an interrupt handler to the given ``channel``. This + interrupt handler will be called when the timer's counter reaches + the given channel :ref:`compare <lang-hardwaretimer-setcompare>` + value. + + ``handler`` should be a function which takes no arguments and has + :ref:`void <lang-void>` value; i.e. it should have signature :: + + void handler(void); + + You can later detach the interrupt using :ref:`detachInterrupt() + <lang-hardwaretimer-detachinterrupt>`. + + .. note:: The function (often called an *interrupt service + routine*, or ISR) should attempt to return as quickly as + possible. :ref:`Blinking the LED <lang-toggleled>`, some + logic, :ref:`PWM <pwm>` updates, and :ref:`Serial + <lang-serial>` writes are fine; writing to + :ref:`SerialUSB <lang-serialusb>` or :ref:`waiting + <lang-waitforbuttonpress>` for user input can take a long + time and prevent other interrupts from firing on time. + + Tip: if you have a :ref:`delay() <lang-delay>` in your + ISR, you're probably doing it wrong. + +.. cpp:function:: void HardwareTimer::attachCompare1Interrupt(voidFuncPtr handler) + + Equivalent to :ref:`attachInterrupt + <lang-hardwaretimer-attachinterrupt>`\ ``(1, handler)``. + +.. cpp:function:: void HardwareTimer::attachCompare2Interrupt(voidFuncPtr handler) + + Equivalent to :ref:`attachInterrupt + <lang-hardwaretimer-attachinterrupt>`\ ``(2, handler)``. + +.. cpp:function:: void HardwareTimer::attachCompare3Interrupt(voidFuncPtr handler) + + Equivalent to :ref:`attachInterrupt + <lang-hardwaretimer-attachinterrupt>`\ ``(3, handler)``. + +.. cpp:function:: void HardwareTimer::attachCompare4Interrupt(voidFuncPtr handler) + + Equivalent to :ref:`attachInterrupt + <lang-hardwaretimer-attachinterrupt>`\ ``(4, handler)``. + +.. _lang-hardwaretimer-setchannelmode: + +.. cpp:function:: void HardwareTimer::setChannelMode(int channel, TimerMode mode) + + Set the given channel of this timer to the given :ref:`mode + <lang-hardwaretimer-modes>`. The parameter ``channel`` is one of + 1, 2, 3, and 4, and corresponds to the compare channel you would + like to set. Refer to the full :ref:`pin mapping table + <pin-mapping-mega-table>` to match up timer channels and pin + numbers. + +.. cpp:function:: void HardwareTimer::setChannel1Mode(TimerMode mode) + + Equivalent to :ref:`setChannelMode <lang-hardwaretimer-setchannelmode>`\ + ``(1, mode)``. + +.. cpp:function:: void HardwareTimer::setChannel2Mode(TimerMode mode) + + Equivalent to :ref:`setChannelMode <lang-hardwaretimer-setchannelmode>`\ + ``(2, mode)``. + +.. cpp:function:: void HardwareTimer::setChannel3Mode(TimerMode mode) + + Equivalent to :ref:`setChannelMode <lang-hardwaretimer-setchannelmode>`\ + ``(3, mode)``. + +.. cpp:function:: void HardwareTimer::setChannel4Mode(TimerMode mode) + + Equivalent to :ref:`setChannelMode <lang-hardwaretimer-setchannelmode>`\ + ``(4, mode)``. + +.. _lang-hardwaretimer-getcompare: + +.. cpp:function:: uint16 HardwareTimer::getCompare(int channel) + + Gets the compare value for the given ``channel``, from 1 to 4. See + :ref:`setCompare() <lang-hardwaretimer-setcompare>`. + +.. cpp:function:: uint16 HardwareTimer::getCompare1() + + Equivalent to :ref:`getCompare <lang-hardwaretimer-getcompare>`\ + ``(1, mode)``. + +.. cpp:function:: uint16 HardwareTimer::getCompare2() + + Equivalent to :ref:`getCompare <lang-hardwaretimer-getcompare>`\ + ``(2, mode)``. + +.. cpp:function:: uint16 HardwareTimer::getCompare3() + + Equivalent to :ref:`getCompare <lang-hardwaretimer-getcompare>`\ + ``(3, mode)``. + +.. cpp:function:: uint16 HardwareTimer::getCompare4() + + Equivalent to :ref:`getCompare <lang-hardwaretimer-getcompare>`\ + ``(4, mode)``. + +.. _lang-hardwaretimer-setcompare: + +.. cpp:function:: void HardwareTimer::setCompare(int channel, uint16 compare) + + Sets the compare value for the given ``channel`` to ``compare``. + If ``compare`` is greater than this timer's overflow value, it will + be truncated to the overflow value. The default compare value is + 65,535 (the largest unsigned 16-bit integer value). + + When the counter reaches this value the interrupt for this channel + will fire if the given ``channel`` :ref:`mode + <lang-hardwaretimer-setchannelmode>` is ``TIMER_OUTPUTCOMPARE`` and + an interrupt is :ref:`attached + <lang-hardwaretimer-attachinterrupt>`. + + By default, this only changes the relative offsets between events + on a single timer ("phase"); they don't control the frequency with + which they occur. However, a common trick is to increment the + compare value manually in the interrupt handler so that the event + will fire again after the increment period. There can be a + different increment value for each channel, so this trick allows + events to be programmed at 4 different rates on a single + timer. Note that function call overheads mean that the smallest + increment rate is at least a few microseconds. + +.. cpp:function:: void HardwareTimer::setCompare1(uint16 compare) + + Equivalent to :ref:`setCompare <lang-hardwaretimer-setcompare>`\ + ``(1, compare)``. + +.. cpp:function:: void HardwareTimer::setCompare2(uint16 compare) + + Equivalent to :ref:`setCompare <lang-hardwaretimer-setcompare>`\ + ``(2, compare)``. + +.. cpp:function:: void HardwareTimer::setCompare3(uint16 compare) + + Equivalent to :ref:`setCompare <lang-hardwaretimer-setcompare>`\ + ``(3, compare)``. + +.. cpp:function:: void HardwareTimer::setCompare4(uint16 compare) + + Equivalent to :ref:`setCompare <lang-hardwaretimer-setcompare>`\ + ``(4, compare)``. + +.. cpp:function:: uint16 HardwareTimer::getCount() + + Gets the current timer count. Due to function call overhead, the + return value will be increasingly accurate with smaller prescale + values. Also see :ref:`setCount() <lang-hardwaretimer-setcount>`. + +.. _lang-hardwaretimer-setcount: + +.. cpp:function:: void HardwareTimer::setCount(uint16 val) + + Set the timer's current count to ``val``. + + Note that there is some function call overhead associated with + calling this method, so using it is not a robust way to get + multiple timers to share a count value. + + If ``val`` exceeds the timer's :ref:`overflow value + <lang-hardwaretimer-getoverflow>`, it is truncated to the overflow + value. + + +.. _lang-hardwaretimer-detachinterrupt: + +.. cpp:function:: void HardwareTimer::detachInterrupt(int channel) + + Remove the interrupt handler attached to the given ``channel``, if + any. The handler will no longer be called by this timer. + +.. cpp:function:: void HardwareTimer::detachCompare1Interrupt() + + Equivalent to :ref:`detachInterrupt + <lang-hardwaretimer-detachinterrupt>`\ ``(1)``. + +.. cpp:function:: void HardwareTimer::detachCompare2Interrupt() + + Equivalent to :ref:`detachInterrupt + <lang-hardwaretimer-detachinterrupt>`\ ``(2)``. + +.. cpp:function:: void HardwareTimer::detachCompare3Interrupt() + + Equivalent to :ref:`detachInterrupt + <lang-hardwaretimer-detachinterrupt>`\ ``(3)``. + +.. cpp:function:: void HardwareTimer::detachCompare4Interrupt() + + Equivalent to :ref:`detachInterrupt + <lang-hardwaretimer-detachinterrupt>`\ ``(4)``. + +.. _lang-hardwaretimer-generateupdate: + +.. cpp:function:: void HardwareTimer::generateUpdate() + + Re-initializes the counter (to 0 in upcounting mode, which is the + default), and generates an update of the prescale and overflow + registers. + +.. _lang-hardwaretimer-getoverflow: + +.. cpp:function:: uint16 HardwareTimer::getOverflow() + + Gets the timer's overflow value. See :ref:`setOverflow() + <lang-hardwaretimer-setoverflow>`. + +.. _lang-hardwaretimer-setoverflow: + +.. cpp:function:: void HardwareTimer::setOverflow(uint16 val) + + Sets the timer overflow (or "reload") value to ``val``. + + When the timer's counter reaches this, value it resets to + zero. Its default value is 65535 (the largest unsigned 16-bit + integer); setting the overflow to anything lower will cause + interrupts to be called more frequently (see :ref:`setPeriod() + <lang-hardwaretimer-setperiod>` function for a shortcut). + + After the next :ref:`timer update + <lang-hardwaretimer-generateupdate>`, this number will be the + maximum value for the timer's channel compare values. + +.. _lang-hardwaretimer-pause: + +.. cpp:function:: void HardwareTimer::pause() + + Stop the timer's counter, without affecting its configuration. + + The timer will no longer count or fire interrupts after this + function is called, until it is resumed. This function is useful + during timer setup periods, in order to prevent interrupts from + firing before the timer is fully configured. + + Note that there is some function call overhead associated with this + method, so using it in concert with :ref:`resume() + <lang-hardwaretimer-resume>` is not a robust way to align multiple + timers to the same count value. + +.. _lang-hardwaretimer-setperiod: + +.. cpp:function:: uint16 HardwareTimer::setPeriod(uint32 microseconds) + + Configure the :ref:`prescaler + <lang-hardwaretimer-getprescalefactor>` and :ref:`overflow + <lang-hardwaretimer-getoverflow>` values to generate a timer reload + with a period as close to the given number of ``microseconds`` as + possible. + + The return value is the new overflow value, which may be used to + set channel compare values. However, if a clock that fires an + interrupt every given number of microseconds is all that is + desired, and the relative "phases" are unimportant, channel compare + values may all be set to 1. + +.. _lang-hardwaretimer-getprescalefactor: + +.. cpp:function:: uint16 HardwareTimer::getPrescaleFactor() + + Returns the timer's prescale factor. See + :ref:`setPrescaleFactor() <lang-hardwaretimer-setprescalefactor>`. + +.. _lang-hardwaretimer-setprescalefactor: + +.. cpp:function:: void HardwareTimer::setPrescaleFactor(uint16 factor) + + Set the timer's prescale factor to ``factor``. + + The prescaler acts as a clock divider to slow down the rate at + which the counter increments. + + For example, the system clock rate is 72MHz, so the counter will + reach 65535 in (13.89 nanoseconds) × (65535 counts) = (910.22 + microseconds), or about a thousand times a second. If the + prescaler equals 1098, then the clock rate is effectively 72MHz / + 1098 = 65.56KHz, and the counter will reach 65536 in (15.25 + microseconds) × (65536 counts) = (0.999 seconds), or about once + per second. + + The :ref:`setPeriod() <lang-hardwaretimer-setperiod>` method may + also be used as a convenient alternative. + +.. cpp:function:: void HardwareTimer::resume() + + Resume a paused timer, without affecting its configuration. + + The timer will resume counting and firing interrupts as + appropriate. + + Note that there is some function call overhead associated with + using this method, so using it in concert with :ref:`pause() + <lang-hardwaretimer-pause>` is not a robust way to align multiple + timers to the same count value. + +.. cpp:function:: timer_dev_num HardwareTimer::getTimerNum() + + Returns the :ref:`timer device number + <lang-hardwaretimer-timer-dev-num>` associated with the timer. For + example, ``Timer1.getTimerNum()`` would return ``TIMER1``. + + In most cases, you should not need to use this function. If you do + use it, be careful; the constant ``TIMER1`` is *not equal* to the + number 1; similarly, ``TIMER2`` is *not* the number 2, etc. Be + sure to refer to the timer device number by name. + +.. _lang-hardwaretimer-modes: + +Timer Modes +^^^^^^^^^^^ +.. doxygenenum:: TimerMode + +.. _lang-hardwaretimer-timer-dev-num: + +Timer Device Numbers +^^^^^^^^^^^^^^^^^^^^ + +These provide a lower-level interface for interacting with timers. +They are mostly useful in context with the :ref:`getTimer() +<lang-hardwaretimer-gettimer>` function. **Be careful** when using +these not to confuse e.g. ``TIMER1`` with the number 1; they are +different. + +.. doxygenenum:: timer_dev_num + +.. _lang-hardwaretimer-convenience: + +.. _lang-hardwaretimer-gettimer: + +Other Functions +^^^^^^^^^^^^^^^ +.. doxygenfunction:: getTimer diff --git a/docs/source/lang/api/highbyte.rst b/docs/source/lang/api/highbyte.rst new file mode 100644 index 0000000..50a1fa6 --- /dev/null +++ b/docs/source/lang/api/highbyte.rst @@ -0,0 +1,59 @@ +.. highlight:: cpp + +.. _lang-highbyte: + +highByte() +========== + +(Macro) Extracts the second lowest byte of an integral data type. + +.. warning:: This macro is provided for compatibility with Arduino + only. It returns the second-least significant byte in an integral + value. It makes sense to call this the "high" byte on a 16-bit + ``int`` microcontroller like the Atmel chips on Arduinos, but it + makes no sense at all on a 32-bit microcontroller like the STM32s + in the Maple line. + + In short: we provide this so that existing Arduino code works as + expected, but **strongly discourage its use** in new programs. + +Syntax +------ + +:: + + highByte(x) + +Parameters +---------- + +**x**: a value of any integral type. + +Returns +------- + +Second lowest byte in **x**. + +Example +------- + +:: + + int x = 0xDEADBEEF; + SerialUSB.println(x, HEX); // prints "BE" + +Arduino Compatibility +--------------------- + +The Maple version of ``highByte()`` is compatible with Arduino. + +See Also +-------- + +- :ref:`lowByte() <lang-lowbyte>` + + + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/interrupts.rst b/docs/source/lang/api/interrupts.rst new file mode 100644 index 0000000..58fd2cc --- /dev/null +++ b/docs/source/lang/api/interrupts.rst @@ -0,0 +1,47 @@ +.. highlight:: cpp + +.. _lang-interrupts: + +interrupts() +============ + +Re-enables interrupts (after they've been disabled by +:ref:`noInterrupts() <lang-nointerrupts>`). Interrupts allow certain +important tasks to happen in the background, and certain interrupts +are enabled by default. + +Some functions will not work while interrupts are disabled, and both +incoming and outgoing communication may be ignored. Interrupts can +slightly disrupt the timing of code, however, and may be disabled for +particularly critical sections of code. + +Library Documentation +--------------------- + +.. doxygenfunction:: interrupts + +Example +------- + +:: + + void setup() {} + + void loop() { + noInterrupts(); + // critical, time-sensitive code here + interrupts(); + // other code here + } + +See Also +-------- + +- :ref:`noInterrupts() <lang-nointerrupts>` +- :ref:`attachInterrupt() <lang-attachinterrupt>` +- :ref:`detachInterrupt() <lang-detachinterrupt>` +- :ref:`Timers reference <timers>` +- :ref:`Timer API <lang-hardwaretimer>` +- :ref:`External interrupts <external-interrupts>` + +.. include:: /lang/cc-attribution.txt diff --git a/docs/source/lang/api/isbuttonpressed.rst b/docs/source/lang/api/isbuttonpressed.rst new file mode 100644 index 0000000..dbff0c9 --- /dev/null +++ b/docs/source/lang/api/isbuttonpressed.rst @@ -0,0 +1,17 @@ +.. _lang-isbuttonpressed: + +isButtonPressed() +================= + +Check whether the board's built-in button (labeled BUT on the +silkscreen) is pressed. + +Library Documentation +--------------------- + +.. doxygenfunction:: isButtonPressed + +See Also +-------- + +- :ref:`lang-waitforbuttonpress` diff --git a/docs/source/lang/api/loop.rst b/docs/source/lang/api/loop.rst new file mode 100644 index 0000000..d8f6183 --- /dev/null +++ b/docs/source/lang/api/loop.rst @@ -0,0 +1,45 @@ +.. highlight:: cpp + +.. _lang-loop: + +loop() +====== + +After creating a :ref:`setup() <lang-setup>` function, which +initializes your sketch, the ``loop()`` function gets called +repeatedly, allowing your program to change and respond. Use it to +actively control your Maple board. + +Example +------- + +:: + + + int buttonPin = 38; + + // setup initializes serial and the button pin + void setup() { + SerialUSB.begin(); + pinMode(buttonPin, INPUT); + } + + // loop() checks the button pin each time it executes, + // and will print 'H' if it is pressed, 'L' otherwise + void loop() { + if (digitalRead(buttonPin) == HIGH) { + SerialUSB.println('H'); + } else { + SerialUSB.println('L'); + } + + delay(1000); + } + +See Also +-------- + +- :ref:`setup() <lang-setup>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/lowbyte.rst b/docs/source/lang/api/lowbyte.rst new file mode 100644 index 0000000..58e622f --- /dev/null +++ b/docs/source/lang/api/lowbyte.rst @@ -0,0 +1,25 @@ +.. _lang-lowbyte: + +lowByte() +========= + +Extracts the low-order (rightmost) byte of a variable (e.g. a +word). + +Syntax +------ + +lowByte(x) + +Parameters +---------- + +**x**: a value of any type. However, if a non-integral type is used, +the results will be strange. + +Returns +------- + +The low byte's value (this will be between 0 and 255). + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/map.rst b/docs/source/lang/api/map.rst new file mode 100644 index 0000000..79122b3 --- /dev/null +++ b/docs/source/lang/api/map.rst @@ -0,0 +1,68 @@ +.. highlight:: cpp + +.. _lang-map: + +map() +===== + +Re-maps a number from one range to another. + +.. contents:: Contents + :local: + +Library Documentation +--------------------- + +.. doxygenfunction:: map + +Discussion +---------- + +``map()`` does not constrain values to within the range, because +out-of-range values are sometimes intended and useful. The +:ref:`constrain() <lang-constrain>` macro may be used either before or +after this function, if limits to the ranges are desired. + +Note that the "lower bounds" of either range may be larger or smaller +than the "upper bounds" so that ``map()`` may be used to reverse a +range of numbers; for example:: + + y = map(x, 1, 50, 50, 1); + +The function also handles negative numbers well, so that this +example :: + + y = map(x, 1, 50, 50, -100); + +is also valid. + +The ``map()`` function uses integer math (its arguments and return +values all have type :ref:`long <lang-long>`), so it will not generate +fractions, when the math might indicate that it should do so. +Fractional remainders are truncated, and are not rounded or averaged. + +Example +------- + +:: + + /* Map an ADC reading (12 bits) to 16-bit PWM (0 to 65,535) */ + + void setup() { + pinMode(0, INPUT_ANALOG); + pinMode(9, PWM); + } + + void loop() { + int val = analogRead(0); + val = map(val, 0, 4095, 0, 65535); + analogWrite(9, val); + } + + +See Also +-------- + +- :ref:`constrain() <lang-constrain>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/max.rst b/docs/source/lang/api/max.rst new file mode 100644 index 0000000..d38eebe --- /dev/null +++ b/docs/source/lang/api/max.rst @@ -0,0 +1,65 @@ +.. highlight:: cpp + +.. _lang-max: + +max() +===== + +(Macro) Calculates the maximum of two numbers. + +Syntax +------ + +:: + + max(x, y) + +Parameters +---------- + +**x**: the first number; may be any number or numeric expression. + +**y**: the second number; may be any number or numeric expression. + + +Returns +------- + +The larger of the two parameter values. + +Example +------- + +:: + + sensVal = max(senVal, 20); // assigns sensVal to the larger of sensVal or 20 + // (effectively ensuring that it is at least 20) + +.. note:: Perhaps counter-intuitively, max() is often used to + constrain the lower end of a variable's range, while :ref:`min() + <lang-min>` is used to constrain the upper end of the range. + +Warning +------- + +Because of the way ``max()`` is implemented, avoid using other +functions inside the parentheses. It may lead to incorrect results:: + + max(a--, 0); // avoid this - yields incorrect results + + a--; // use this instead - + max(a, 0); // keep other operations outside max() + +Arduino Compatibility +--------------------- + +The Maple version of ``max()`` is compatible with Arduino. + +See Also +-------- + +- :ref:`min() <lang-min>` +- :ref:`constrain() <lang-constrain>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/micros.rst b/docs/source/lang/api/micros.rst new file mode 100644 index 0000000..f12976b --- /dev/null +++ b/docs/source/lang/api/micros.rst @@ -0,0 +1,46 @@ +.. highlight:: cpp + +.. _lang-micros: + +micros() +======== + +Returns the number of microseconds since the Maple board began running +the current program. This number will overflow (go back to zero), +after approximately 70 minutes. + +.. note:: There are 1,000 microseconds in a millisecond, and 1,000,000 + microseconds in a second. + +Library Documentation +--------------------- + +.. doxygenfunction:: micros + +Example +------- + +:: + + unsigned int time; + + void setup() { + } + + void loop() { + SerialUSB.print("Time: "); + time = micros(); + // prints time since program started + SerialUSB.println(time); + // wait a second so as not to send massive amounts of data + delay(1000); + } + +See Also +-------- + +- :ref:`millis() <lang-millis>` +- :ref:`delay() <lang-delay>` +- :ref:`delayMicroseconds() <lang-delaymicroseconds>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/millis.rst b/docs/source/lang/api/millis.rst new file mode 100644 index 0000000..54e4507 --- /dev/null +++ b/docs/source/lang/api/millis.rst @@ -0,0 +1,52 @@ +.. highlight:: cpp + +.. _lang-millis: + +millis() +======== + +Returns the number of milliseconds since the Maple board began running +the current program. This number will overflow (go back to zero) after +approximately 50 days. + +Library Documentation +--------------------- + +.. doxygenfunction:: millis + +Example +------- + +The following time prints the value returned by ``millis()`` roughly +once per second:: + + unsigned int time; + + void setup() { + } + + void loop() { + SerialUSB.print("Time: "); + time = millis(); + // prints time since program started + Serial.println(time); + + // wait a second so as not to send massive amounts of data + delay(1000); + } + +Tip +--- + +Since the return value for ``millis()`` is an :ref:`unsigned long +<lang-unsignedlong>`, overflow errors may occur if you try to do math +with other data types, such as :ref:`ints <lang-int>`. + +See Also +-------- + +- :ref:`micros <lang-micros>` +- :ref:`delay <lang-delay>` +- :ref:`delayMicroseconds <lang-delaymicroseconds>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/min.rst b/docs/source/lang/api/min.rst new file mode 100644 index 0000000..1245f6f --- /dev/null +++ b/docs/source/lang/api/min.rst @@ -0,0 +1,66 @@ +.. highlight:: cpp + +.. _lang-min: + +min() +===== + +(Macro) Calculates the minimum of two numbers. + +Syntax +------ + +:: + + min(x,y) + +Parameters +---------- + +**x**: the first number; may be any number or numeric expression. + +**y**: the second number; may be any number or numeric expression. + +Returns +------- + +The smaller of the two numbers. + +Example +------- + +:: + + sensVal = min(sensVal, 100); // assigns sensVal to the smaller of sensVal or 100 + // ensuring that it never gets above 100. + + +.. note:: Perhaps counter-intuitively, max() is often used to + constrain the lower end of a variable's range, while min() is used + to constrain the upper end of the range. + + +Warning +------- + +Because of the way ``min()`` is implemented, avoid using other +functions inside the parentheses. It may lead to incorrect results:: + + min(a++, 100); // avoid this - yields incorrect results + + a++; // use this instead - + min(a, 100); // keep other operations outside min() + +Arduino Compatibility +--------------------- + +The Maple version of ``min()`` is compatible with Arduino. + +See Also +-------- + +- :ref:`max() <lang-max>` +- :ref:`constrain() <lang-constrain>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/nointerrupts.rst b/docs/source/lang/api/nointerrupts.rst new file mode 100644 index 0000000..68f0498 --- /dev/null +++ b/docs/source/lang/api/nointerrupts.rst @@ -0,0 +1,47 @@ +.. highlight:: cpp + +.. _lang-nointerrupts: + +noInterrupts() +============== + +Description +----------- + +Disables interrupts. Interrupts allow certain important tasks to +happen in the background and are enabled by default. Some functions +will not work while interrupts are disabled, and incoming +communication may be ignored. Interrupts can slightly disrupt the +timing of code, however, and may be disabled for particularly critical +sections of code. + +Library Documentation +--------------------- + +.. doxygenfunction:: noInterrupts + +Example +------- + +:: + + void setup() {} + + void loop() { + noInterrupts(); + // critical, time-sensitive code here + interrupts(); + // other code here + } + +See Also +-------- + +- :ref:`interrupts() <lang-interrupts>` +- :ref:`attachInterrupt() <lang-attachinterrupt>` +- :ref:`detachInterrupt() <lang-detachinterrupt>` +- :ref:`Timers reference <timers>` +- :ref:`Timer API <lang-hardwaretimer>` +- :ref:`External interrupts <external-interrupts>` + +.. include:: /lang/cc-attribution.txt diff --git a/docs/source/lang/api/pinmode.rst b/docs/source/lang/api/pinmode.rst new file mode 100644 index 0000000..03cbcfa --- /dev/null +++ b/docs/source/lang/api/pinmode.rst @@ -0,0 +1,79 @@ +.. highlight:: cpp + +.. _lang-pinmode: + +pinMode() +========= + +.. contents:: Contents + :local: + +Library Documentation +--------------------- + +.. doxygenfunction:: pinMode + +.. _lang-pinmode-wiringpinmode: + +.. doxygenenum:: WiringPinMode + +Discussion +---------- + +``pinMode()`` is usually called within :ref:`lang-setup` in order to +configure a pin for a certain usage (although it may be called +anywhere). + +Example +------- + +:: + + int ledPin = 13; // LED connected to digital pin 13 + + void setup() { + pinMode(ledPin, OUTPUT); // sets the digital pin as output + } + + void loop() { + digitalWrite(ledPin, HIGH); // sets the LED on + delay(1000); // waits for a second + digitalWrite(ledPin, LOW); // sets the LED off + delay(1000); // waits for a second + } + +Arduino Compatibility +--------------------- + +.. TODO check out Arduino vs. Maple static discilpline cutoffs to +.. ensure accuracy of following: + +The libmaple implementation of ``pinMode()`` supports the ``INPUT`` +and ``OUTPUT`` modes with semantics identical to that of the Arduino +function (however, be advised that the Maple, as a 3.3V device, will +only drive 3.3V to an ``OUTPUT`` pin that has been set ``HIGH``). + +``INPUT_ANALOG`` and ``PWM`` modes were added because the Maple does +not distinguish between analog and digital pins the same way the +Arduino does. Unlike the Arduino, you **must call** ``pinMode()`` to +set up a pin for these purposes before a call to, e.g., +:ref:`lang-analogRead`. In practice, this should only add a few lines +to your :ref:`lang-setup` function. + +.. TODO verify following before putting it in: + +.. ``OUTPUT_OPEN_DRAIN``, ``INPUT_PULLUP``, ``INPUT_PULLDOWN``, and +.. ``PWM_OPEN_DRAIN`` modes represent functionality not currently +.. available on Arduino boards. + +See also +-------- + +- :ref:`lang-constants` +- :ref:`lang-digitalwrite` +- :ref:`lang-digitalread` +- Maple :ref:`GPIO <gpio>` reference page + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/pow.rst b/docs/source/lang/api/pow.rst new file mode 100644 index 0000000..4280400 --- /dev/null +++ b/docs/source/lang/api/pow.rst @@ -0,0 +1,23 @@ +.. _lang-pow: + +pow() +===== + +Calculates the value of a number raised to a power. + +Library Documentation +--------------------- + +.. doxygenfunction:: pow + +.. TODO LATER some examples + +See Also +-------- + +- :ref:`sqrt() <lang-sqrt>` +- :ref:`float <lang-float>` +- :ref:`double <lang-double>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/pwmwrite.rst b/docs/source/lang/api/pwmwrite.rst new file mode 100644 index 0000000..2c858ab --- /dev/null +++ b/docs/source/lang/api/pwmwrite.rst @@ -0,0 +1,56 @@ +.. highlight:: cpp + +.. _lang-pwmwrite: + +pwmWrite() +========== + +Writes a :ref:`PWM wave <pwm>` to a pin. You can use this to make an +LED get brighter or dimmer, control a servomotor, etc. After a call to +pwmWrite(), the pin will output a steady square wave with the given +duty cycle. You can change the duty cycle later by calling pwmWrite() +again with the same pin and a different duty. + +On the Maple, the pins which support PWM are: 0, 1, 2, 3, 5, 6, 7, 8, +9, 11, 12, 14, 24, 27, and 28. + +The Arduino function :ref:`analogWrite() <lang-analogwrite>` is an +alias for ``pwmWrite()``, but it is badly named, and its use is +discouraged. + +.. contents:: Contents + :local: + +Library Documentation +--------------------- + +.. doxygenfunction:: pwmWrite + +Example +------- + +Sets the output to the LED proportional to the value read from the +potentiometer:: + + int analogPin = 3; // potentiometer connected to analog pin 3 + int val = 0; // variable to store the read value + + void setup() { + pinMode(BOARD_LED_PIN, OUTPUT); // sets the LED pin as output + + pinMode(analogPin, PWM); // sets the potentiometer pin as PWM + // output + } + + void loop() { + val = analogRead(analogPin); // read the input pin + + analogWrite(BOARD_LED_PIN, val / 16); // analogRead values go from 0 + // to 4095, analogWrite values + // from 0 to 65535 + } + +See Also +-------- + +- :ref:`Maple PWM tutorial <pwm>` diff --git a/docs/source/lang/api/random.rst b/docs/source/lang/api/random.rst new file mode 100644 index 0000000..f2a9762 --- /dev/null +++ b/docs/source/lang/api/random.rst @@ -0,0 +1,73 @@ +.. highlight:: cpp + +.. _lang-random: + +random() +======== + +The ``random()`` function generates pseudo-random numbers. + +.. TODO keep tracking Sphinx/Breathe's ability to reference overloaded +.. functions so we can use doxygenfunction instead of manually +.. documenting this. + +Library Documentation +--------------------- + +.. cpp:function:: random(long max) + + Same as a call to ``random(0, max)``. + +.. cpp:function:: random(long min, long max) + + Generate a pseudo-random number with given lower and upper bounds. + + *Parameters* + + - ``min`` - Lower bound on the returned value, inclusive + - ``max`` - Upper bound on the returned value, exclusive + + *Returns*: A pseudo-random number in the range [min, max). + +Discussion +---------- + +If it is important for a sequence of values generated by +:ref:`random() <lang-random>` to differ, on subsequent executions of a +sketch, use :ref:`randomSeed() <lang-randomseed>` to initialize the +random number generator with a fairly random input, such as +:ref:`analogRead() <lang-analogread>` on an unconnected pin. + +Conversely, it can occasionally be useful to use pseudorandom +sequences that repeat exactly. This can be accomplished by calling +``randomSeed()`` with a fixed number, before starting the random +sequence. + +Example +------- + +The following sketch initializes the random seed based on an :ref:`ADC +<adc>` reading of pin 0. If this pin is unconnected, the Sketch +should print different values to the :ref:`serial monitor +<ide-serial-monitor>` each time it is run:: + + long randNumber; + + void setup() { + pinMode(0, INPUT_ANALOG); + randomSeed(analogRead(0)); + } + + void loop() { + randNumber = random(300); + SerialUSB.println(randNumber); + + delay(50); + } + +See Also +-------- + +- :ref:`randomSeed() <lang-randomseed>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/randomseed.rst b/docs/source/lang/api/randomseed.rst new file mode 100644 index 0000000..d0a15b7 --- /dev/null +++ b/docs/source/lang/api/randomseed.rst @@ -0,0 +1,60 @@ +.. highlight:: cpp + +.. _lang-randomseed: + +randomSeed() +============ + +``randomSeed()`` initializes the `pseudorandom number generator +<http://en.wikipedia.org/wiki/Pseudorandom_number_generator>`_, +causing it to start at an arbitrary point in its random sequence. +This sequence, while very long, and random, is always the same. + + +Library Documentation +--------------------- + +.. doxygenfunction:: randomSeed + +Discussion +---------- + +If it is important for a sequence of values generated by +:ref:`random() <lang-random>` to differ, on subsequent executions of a +sketch, use ``randomSeed()`` to initialize the random number generator +with a fairly random input, such as :ref:`analogRead() +<lang-analogread>` on an unconnected pin. + +Conversely, it can occasionally be useful to use pseudorandom +sequences that repeat exactly. This can be accomplished by calling +``randomSeed()`` with a fixed number, before starting the random +sequence. + +Example +------- + +The following sketch initializes the random seed based on an :ref:`ADC +<adc>` reading of pin 0. If this pin is unconnected, the Sketch +should print different values to the :ref:`serial monitor +<ide-serial-monitor>` each time it is run:: + + long randNumber; + + void setup() { + pinMode(0, INPUT_ANALOG); + randomSeed(analogRead(0)); + } + + void loop() { + randNumber = random(300); + SerialUSB.println(randNumber); + + delay(50); + } + +See Also +-------- + +- :ref:`random() <lang-random>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/serial.rst b/docs/source/lang/api/serial.rst new file mode 100644 index 0000000..ca89b31 --- /dev/null +++ b/docs/source/lang/api/serial.rst @@ -0,0 +1,226 @@ +.. _lang-serial: + +Serial Ports (``Serial1``, ``Serial2``, ``Serial3``) +==================================================== + +Used for communication between the Maple board and a computer or other +devices. + +.. contents:: Contents + :local: + +Introduction +------------ + +The Maple has three serial ports (also known as a UARTs or USARTs): +``Serial1``, ``Serial2``, and ``Serial3``. They communicate using the +pins summarized in the following table: + +.. list-table:: + :header-rows: 1 + + * - Serial port + - TX, RX, CK + - CTS, RTS (if present) + + * - ``Serial1`` + - 7, 8, 6 + - + + * - ``Serial2`` + - 1, 0, 10 + - 2, 3 + + * - ``Serial3`` + - 29, 30, 31 + - 32, 33 + +Thus, if you use a particular serial port, you cannot also use its +communication pins for other purposes at the same time. + +If you want to communicate with the Maple using the provided USB port, +use :ref:`SerialUSB <lang-serialusb>` instead. + +To use them to communicate with an external TTL serial device, connect +the TX pin to your device's RX pin, the RX to your device's TX pin, +and the ground of your Maple to your device's ground. + +.. warning:: Don't connect these pins directly to an RS232 serial + port; they operate at +/- 12V and can damage your board. + + +Library Documentation +--------------------- + +All of the ``Serial[1,2,3]`` objects are instances of the +``HardwareSerial`` class, which is documented in this section. (This +means that you can use any of these functions on any of ``Serial1``, +``Serial2``, and ``Serial3``). + +.. cpp:class:: HardwareSerial + + Serial port class. Predefined instances are ``Serial1``, + ``Serial2``, and ``Serial3``. + +.. cpp:function:: HardwareSerial::begin(unsigned int baud) + + Set up a ``HardwareSerial`` object for communications. This method + must be called before attempting to use the ``HardwareSerial`` + object (typically, you call this in your :ref:`setup() + <lang-setup>` function). + +.. cpp:function:: HardwareSerial::end() + + Disables the USART associated with this object, allowing any + associated communication pins to be used for other purposes. + +.. cpp:function:: unsigned int HardwareSerial::available() + + Returns the number of bytes available for reading. + +.. cpp:function:: unsigned char HardwareSerial::read() + + Returns the next available, unread character. If there are no + available characters (you can check this with :cpp:func:`available + <HardwareSerial::available>`), the call will block until one + becomes available. + +.. cpp:function:: HardwareSerial::flush() + + Removes the contents of the Serial's associated USART RX FIFO. + That is, clears any buffered characters, so that the next character + read is guaranteed to be new. + +.. cpp:function:: HardwareSerial::print(unsigned char b) + + Print the given byte over the USART. + +.. cpp:function:: HardwareSerial::print(char c) + + Print the given character over the USART. 7-bit clean characters + are typically interpreted as ASCII text. + +.. cpp:function:: HardwareSerial::print(const char *str) + + Print the given null-terminated string over the USART. + +.. cpp:function:: HardwareSerial::print(int n) + + Print the argument's digits over the USART, in decimal format. + Negative values will be prefixed with a ``'-'`` character. + +.. cpp:function:: HardwareSerial::print(unsigned int n) + + Print the argument's digits over the USART, in decimal format. + +.. cpp:function:: HardwareSerial::print(long n) + + Print the argument's digits over the USART, in decimal format. + Negative values will be prefixed with a ``'-'`` character. + +.. cpp:function:: HardwareSerial::print(unsigned long n) + + Print the argument's digits over the USART, in decimal format. + +.. cpp:function:: HardwareSerial::print(long n, int base) + + Print the digits of ``n`` over the USART, in base ``base`` (which + may be between 2 and 16). The ``base`` value 2 corresponds to + binary, 8 to octal, 10 to decimal, and 16 to hexadecimal. Negative + values will be prefixed with a ``'-'`` character. + +.. cpp:function:: HardwareSerial::print(double n) + + Print ``n``, accurate to 2 digits after the decimal point. + +.. _lang-serial-println: + +.. cpp:function:: HardwareSerial::println(char c) + + Like ``print(c)``, followed by ``"\r\n"``. + +.. cpp:function:: HardwareSerial::println(const char *c) + + Like ``print(c)``, followed by ``"\r\n"``. + +.. cpp:function:: HardwareSerial::println(unsigned char b) + + Like ``print(b)``, followed by ``"\r\n"``. + +.. cpp:function:: HardwareSerial::println(int n) + + Like ``print(n)``, followed by ``"\r\n"``. + +.. cpp:function:: HardwareSerial::println(unsigned int n) + + Like ``print(n)``, followed by ``"\r\n"``. + +.. cpp:function:: HardwareSerial::println(long n) + + Like ``print(n)``, followed by ``"\r\n"``. + +.. cpp:function:: HardwareSerial::println(unsigned long n) + + Like ``print(n)``, followed by ``"\r\n"``. + +.. cpp:function:: HardwareSerial::println(long n, int base) + + Like ``print(n, b)``, followed by ``"\r\n"``. + +.. cpp:function:: HardwareSerial::println(double n) + + Like ``print(n)``, followed by ``"\r\n"``. + +.. cpp:function:: HardwareSerial::println() + + Prints ``"\r\n"`` over the USART. + +.. cpp:function:: HardwareSerial::write(unsigned char ch) + + Sends one character over the USART. This function is currently + blocking, although nonblocking writes are a planned future + extension. + + This is a low-level function. One of the ``print()`` or + ``println()`` functions is likely to be more useful when printing + multiple characters, when formatting numbers for printing, etc. + +.. cpp:function:: HardwareSerial::write(const char* str) + + Send the given null-terminated character string over the USART. + + This is a low-level function. One of the ``print()`` or + ``println()`` functions is likely to be more useful when printing + multiple characters, when formatting numbers for printing, etc. + +.. cpp:function:: HardwareSerial::write(void *buf, unsigned int size) + + Writes the first ``size`` bytes of ``buf`` over the USART. Each + byte is transmitted as an individual character. + + This is a low-level function. One of the ``print()`` or + ``println()`` functions is likely to be more useful when printing + multiple characters, when formatting numbers for printing, etc. + +Arduino Compatibility Note +-------------------------- + +Unlike the Arduino, none of the Maple's serial ports is connected to +the USB port on the Maple board (for that, use :ref:`SerialUSB +<lang-serialusb>`). Thus, to use these pins to communicate with your +personal computer, you will need an additional USB-to-serial adaptor. + +.. TODO LATER port these examples over + +.. Examples +.. -------- + +.. - `ASCII Table <http://arduino.cc/en/Tutorial/ASCIITable>`_ +.. - `Dimmer <http://arduino.cc/en/Tutorial/Dimmer>`_ +.. - `Graph <http://arduino.cc/en/Tutorial/Graph>`_ +.. - `Physical Pixel <http://arduino.cc/en/Tutorial/PhysicalPixel>`_ +.. - `Virtual Color Mixer <http://arduino.cc/en/Tutorial/VirtualColorMixer>`_ +.. - `Serial Call Response <http://arduino.cc/en/Tutorial/SerialCallResponse>`_ +.. - `Serial Call Response ASCII <http://arduino.cc/en/Tutorial/SerialCallResponseASCII>`_ + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/serialusb.rst b/docs/source/lang/api/serialusb.rst new file mode 100644 index 0000000..3bb8c00 --- /dev/null +++ b/docs/source/lang/api/serialusb.rst @@ -0,0 +1,243 @@ +.. highlight:: cpp + +.. _lang-serialusb: + +``SerialUSB`` +============= + +Used for communication between the Maple board and a computer. + +.. contents:: Contents + :local: + +Introduction +------------ + +In addition to three :ref:`serial ports <lang-serial>`, the Maple's +STM32 microprocessor includes a dedicated USB peripheral. This +peripheral is used to emulate a regular serial port for use as a +terminal (text read/write). The emulated terminal is relatively slow +and inefficient; it is best for transferring data at regular serial +speeds (kilobaud). + +Library access to the emulated serial port is provided through the +``SerialUSB`` object. You can mostly use ``SerialUSB`` as a drop-in +replacement for ``Serial1``, ``Serial2``, and ``Serial3``. + +.. warning:: The ``SerialUSB`` functionality includes a 50 millisecond + timeout for writes, and does not try to detect if the USB host is + "really" connected, or just enumerated and initialized. + + This means that if you have a number of calls to one of the + ``SerialUSB`` ``write()`` or ``print()`` functions in your code, + and you are not monitoring the emulated on a computer, your program + will run much, much slower than if it is being monitored or totally + disconnected (run off of a battery). + + You can avoid this behavior by :ref:`deciphering the port status + using the DTR and RTS line status <lang-serialusb-safe-print>`; the + behavior of these control lines is platform dependent and we no + longer interpret them by default. + +Library Documentation +--------------------- + +The ``SerialUSB`` object is an instance of the ``USBSerial`` class, +which is documented in this section. This means that you can use any +of these functions by writing +``SerialUSB.functionName(arguments...)``. For example, to print the +message "hello, world!", you can write ``USBSerial.println("hello, +world!")``. + +.. cpp:class:: USBSerial + + Emulated serial-over-USB class. ``SerialUSB`` is the predefined + (singleton) instance. + +.. _lang-serialusb-begin: + +.. cpp:function:: USBSerial::begin() + + Set up the USB peripheral for emulated serial communication. The + peripheral is configured this way by default; calling this function + should only be necessary if you have disabled the peripheral using + ``SerialUSB.end()``. + +.. _lang-serialusb-end: + +.. cpp:function:: USBSerial::end() + + Disables the USB peripheral. Note that using this function will + terminate all USB communications between the Maple and the USB + host; in particular, it implies that you won't be able to upload + any new programs without resetting the board or using + :ref:`perpetual bootloader mode + <troubleshooting-perpetual-bootloader>`. + +.. cpp:function:: unsigned int USBSerial::available() + + Returns the number of bytes available for reading. + +.. _lang-serialusb-read: + +.. cpp:function:: unsigned char USBSerial::read() + + Returns the next available, unread character. If there are no + available characters (you can check this with :cpp:func:`available + <USBSerial::available>`), the call will block until one + becomes available. + +.. cpp:function:: USBSerial::print(unsigned char b) + + Print the given byte over the USB connection. + +.. cpp:function:: USBSerial::print(char c) + + Print the given character over the USB connection. 7-bit clean characters + are typically interpreted as ASCII text. + +.. cpp:function:: USBSerial::print(const char *str) + + Print the given null-terminated string over the USB connection. + +.. cpp:function:: USBSerial::print(int n) + + Print the argument's digits over the USB connection, in decimal format. + Negative values will be prefixed with a ``'-'`` character. + +.. cpp:function:: USBSerial::print(unsigned int n) + + Print the argument's digits over the USB connection, in decimal format. + +.. cpp:function:: USBSerial::print(long n) + + Print the argument's digits over the USB connection, in decimal + format. Negative values will be prefixed with a ``'-'`` character. + +.. cpp:function:: USBSerial::print(unsigned long n) + + Print the argument's digits over the USB connection, in decimal + format. + +.. cpp:function:: USBSerial::print(long n, int base) + + Print the digits of ``n`` over the USB connection, in base ``base`` + (which may be between 2 and 16). The ``base`` value 2 corresponds + to binary, 8 to octal, 10 to decimal, and 16 to hexadecimal. + Negative values will be prefixed with a ``'-'`` character. + +.. cpp:function:: USBSerial::print(double n) + + Print ``n``, accurate to 2 digits after the decimal point. + +.. _lang-serialusb-println: + +.. cpp:function:: USBSerial::println(char c) + + Like ``print(c)``, followed by ``"\r\n"``. + +.. cpp:function:: USBSerial::println(const char *c) + + Like ``print(c)``, followed by ``"\r\n"``. + +.. cpp:function:: USBSerial::println(unsigned char b) + + Like ``print(b)``, followed by ``"\r\n"``. + +.. cpp:function:: USBSerial::println(int n) + + Like ``print(n)``, followed by ``"\r\n"``. + +.. cpp:function:: USBSerial::println(unsigned int n) + + Like ``print(n)``, followed by ``"\r\n"``. + +.. cpp:function:: USBSerial::println(long n) + + Like ``print(n)``, followed by ``"\r\n"``. + +.. cpp:function:: USBSerial::println(unsigned long n) + + Like ``print(n)``, followed by ``"\r\n"``. + +.. cpp:function:: USBSerial::println(long n, int base) + + Like ``print(n, b)``, followed by ``"\r\n"``. + +.. cpp:function:: USBSerial::println(double n) + + Like ``print(n)``, followed by ``"\r\n"``. + +.. cpp:function:: USBSerial::println() + + Prints ``"\r\n"`` over the USB connection. + +.. cpp:function:: USBSerial::write(unsigned char ch) + + Sends one character over the USB connection. This function is + currently blocking, although nonblocking writes are a planned + future extension. + + This is a low-level function. One of the ``print()`` or + ``println()`` functions is likely to be more useful when printing + multiple characters, when formatting numbers for printing, etc. + +.. cpp:function:: USBSerial::write(const char* str) + + Send the given null-terminated character string over the USB + connection. + + This is a low-level function. One of the ``print()`` or + ``println()`` functions is likely to be more useful when printing + multiple characters, when formatting numbers for printing, etc. + +.. cpp:function:: USBSerial::write(void *buf, unsigned int size) + + Writes the first ``size`` bytes of ``buf`` over the USB connection. + Each byte is transmitted as an individual character. + + This is a low-level function. One of the ``print()`` or + ``println()`` functions is likely to be more useful when printing + multiple characters, when formatting numbers for printing, etc. + +Examples +-------- + +.. _lang-serialusb-safe-print: + +**Safe print**: This function should run smoothly and not block; the +LED should blink at roughly the same speed whether being monitored, +running from battery, or connected but not monitored. You may need to +experiment with the DTR/RTS logic for your platform and device +configuration. :: + + #define LED_PIN 13 + + void setup() { + /* Set up the LED to blink */ + pinMode(LED_PIN, OUTPUT); + } + + void loop() { + // LED will stay off if we are disconnected; + // will blink quickly if USB is unplugged (battery etc) + if(SerialUSB.isConnected()) { + digitalWrite(LED_PIN, 1); + } + delay(100); + + // If this logic fails to detect if bytes are going to + // be read by the USB host, then the println() will fully + // many times, causing a very slow LED blink. + // If the characters are printed and read, the blink will + // only slow a small amount when "really" connected, and fast + // when the virtual port is only configured. + if(SerialUSB.isConnected() && (SerialUSB.getDTR() || SerialUSB.getRTS())) { + for(int i=0; i<10; i++) { + SerialUSB.println(123456,BIN); + } + } + digitalWrite(LED_PIN, 0); + delay(100); + } + diff --git a/docs/source/lang/api/setup.rst b/docs/source/lang/api/setup.rst new file mode 100644 index 0000000..837ddd6 --- /dev/null +++ b/docs/source/lang/api/setup.rst @@ -0,0 +1,29 @@ +.. highlight:: cpp + +.. _lang-setup: + +setup() +======= + +The ``setup()`` function is called when a sketch starts. Use it to +initialize :ref:`variables <lang-variables>`, :ref:`pin modes +<lang-pinmode>`, start using :ref:`libraries <libraries>`, etc. The +``setup()`` function will only run once, after each power-up or reset +of the Maple board. + +Example +------- + +:: + + int buttonPin = 38; + + void setup() { + pinMode(buttonPin, INPUT); + } + + void loop() { + // ... + } + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/sin.rst b/docs/source/lang/api/sin.rst new file mode 100644 index 0000000..398b8f3 --- /dev/null +++ b/docs/source/lang/api/sin.rst @@ -0,0 +1,32 @@ +.. _lang-sin: + +sin() +===== + +Calculates the `sine <http://en.wikipedia.org/wiki/Sine>`_ of an +angle. + +Library Documentation +--------------------- + +.. doxygenfunction:: sin + +Arduino Compatibility +--------------------- + +The Maple version of ``sin()`` is compatible with Arduino. + +Note that the Maple implementation comes from `newlib +<http://sourceware.org/newlib/>`_\ , while Arduino's is that of +`avr-libc <http://avr-libc.nongnu.org/>`_\ . + +See Also +-------- + +- :ref:`cos <lang-cos>` +- :ref:`tan <lang-tan>` +- :ref:`float <lang-float>` +- :ref:`double <lang-double>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/sq.rst b/docs/source/lang/api/sq.rst new file mode 100644 index 0000000..bd32648 --- /dev/null +++ b/docs/source/lang/api/sq.rst @@ -0,0 +1,46 @@ +.. highlight:: cpp + +.. _lang-sq: + +sq() +==== + +(Macro) computes the square of a number. + +Syntax +------ + +:: + + sq(a) + +Parameters +---------- + +**a**: the number. + +Returns +------- + +**a** squared (**a** × **a**). + +Warning +------- + +Because of the way ``sq()`` is implemented, avoid using other +functions or causing side effects inside the parentheses, as it may +lead to incorrect results:: + + b = sq(a++); // avoid this - yields incorrect results + + b = sq(a); // use this instead - + a++; // keep other operations outside sq() + + +Arduino Compatibility +--------------------- + +Maple's implementation of ``sq()`` is compatible with Arduino. + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/tan.rst b/docs/source/lang/api/tan.rst new file mode 100644 index 0000000..4bbe0db --- /dev/null +++ b/docs/source/lang/api/tan.rst @@ -0,0 +1,31 @@ +.. _lang-tan: + +tan() +===== + +Calculates the tangent of an angle. + +Library Documentation +--------------------- + +.. doxygenfunction:: tan + +Arduino Compatibility +--------------------- + +The Maple version of ``tan()`` is compatible with Arduino. + +Note that the Maple implementation comes from `newlib +<http://sourceware.org/newlib/>`_\ , while Arduino's is that of +`avr-libc <http://avr-libc.nongnu.org/>`_\ . + +See Also +-------- + + +- :ref:`sin <lang-sin>` +- :ref:`cos <lang-cos>` +- :ref:`float <lang-float>` +- :ref:`double <lang-double>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/toggleled.rst b/docs/source/lang/api/toggleled.rst new file mode 100644 index 0000000..0cc20c2 --- /dev/null +++ b/docs/source/lang/api/toggleled.rst @@ -0,0 +1,17 @@ +.. _lang-toggleled: + +toggleLED() +=========== + +Switches the LED from off to on, or on to off. + +Library Documentation +--------------------- + +.. doxygenfunction:: toggleLED + +See Also +-------- + +- :ref:`BOARD_LED_PIN <lang-constants-led>` +- :ref:`togglePin() <lang-togglepin>` diff --git a/docs/source/lang/api/togglepin.rst b/docs/source/lang/api/togglepin.rst new file mode 100644 index 0000000..290718d --- /dev/null +++ b/docs/source/lang/api/togglepin.rst @@ -0,0 +1,17 @@ +.. _lang-togglepin: + +togglePin() +=========== + +Switches a digital output pin from :ref:`HIGH <lang-constants-high>` +to :ref:`LOW <lang-constants-low>`, or from LOW to HIGH. + +Library Documentation +--------------------- + +.. doxygenfunction:: togglePin + +See Also +-------- + +- :ref:`toggleLED() <lang-toggleled>` diff --git a/docs/source/lang/api/volatile.rst b/docs/source/lang/api/volatile.rst new file mode 100644 index 0000000..276bb6a --- /dev/null +++ b/docs/source/lang/api/volatile.rst @@ -0,0 +1,65 @@ +.. highlight:: cpp + +.. _lang-volatile: + +``volatile`` +============ + +The ``volatile`` keyword known is a variable *qualifier*. It is +usually used before the datatype of a variable, to modify the way in +which the compiler treats the variable. + +Declaring a variable ``volatile`` is a directive to the compiler. The +compiler is software which translates your C++ code into the machine +code, which are the real instructions for the STM32 chip in the +Maple. (The particular compiler we provide for use with the Maple is a +version of :ref:`GCC <arm-gcc>`). + +Specifically, it directs the compiler to read the variable's value +fresh every time it is used, rather than "backing up" the value and +reading from its backup copy. (Compilers often "back up" a variable's +value in RAM into a storage location called a *register*; this is done +for efficiency). + +A variable should be declared ``volatile`` whenever its value can be +changed by something beyond the control of the code section in which +it appears, such as an :ref:`external interrupt +<external-interrupts>`. On the Maple, the only place that this is +likely to occur is in sections of code associated with interrupts. + +Example +------- + +:: + + // toggles LED when interrupt pin changes state + + int pin = 13; + volatile int state = LOW; + + void setup() { + pinMode(pin, OUTPUT); + attachInterrupt(0, blink, CHANGE); + } + + void loop() { + digitalWrite(pin, state); + } + + void blink() { + if (state == HIGH) { + state = LOW; + } else { + // state must be HIGH + state = HIGH; + } + } + +See also +-------- + +- :ref:`External Interrupts <external-interrupts>` +- :ref:`lang-attachinterrupt` +- :ref:`lang-detachinterrupt` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/api/waitforbuttonpress.rst b/docs/source/lang/api/waitforbuttonpress.rst new file mode 100644 index 0000000..34c5066 --- /dev/null +++ b/docs/source/lang/api/waitforbuttonpress.rst @@ -0,0 +1,17 @@ +.. _lang-waitforbuttonpress: + +waitForButtonPress() +==================== + +Wait for the board's built-in button (labeled BUT on the silkscreen) +to be pressed, possibly with timeout. + +Library Documentation +--------------------- + +.. doxygenfunction:: waitForButtonPress + +See Also +-------- + +- :ref:`lang-isbuttonpressed` diff --git a/docs/source/lang/cc-attribution.txt b/docs/source/lang/cc-attribution.txt new file mode 100644 index 0000000..e100140 --- /dev/null +++ b/docs/source/lang/cc-attribution.txt @@ -0,0 +1,9 @@ +.. Included in all this directory's files in order to satisfy the +.. Arduino CC Attribution-ShareAlike 3.0 License + +.. admonition:: License and Attribution + + This documentation page was adapted from the `Arduino Reference + Documentation <http://arduino.cc/en/Reference/HomePage>`_\ , which + is released under a `Creative Commons Attribution-ShareAlike 3.0 + License <http://creativecommons.org/licenses/by-sa/3.0/>`_. diff --git a/docs/source/lang/cpp/arithmetic.rst b/docs/source/lang/cpp/arithmetic.rst new file mode 100644 index 0000000..91fe22e --- /dev/null +++ b/docs/source/lang/cpp/arithmetic.rst @@ -0,0 +1,127 @@ +.. highlight:: cpp + +.. _lang-arithmetic: + +Arithmetic Operators (``+``, ``-``, ``*``, ``/``) +================================================= + +The operators ``+``, ``-``, ``*``, and ``/`` respectively evaluate to +the sum, difference, product, or quotient (respectively) of the two +operands. The operation is conducted using the data type of the +operands, so, for example, ``9 / 4`` gives ``2`` since 9 and 4 are +:ref:`int variables <lang-int>`. + +This also means that the operation can overflow if the result is +larger than that which can be stored in the data type (e.g. adding 1 +to an :ref:`lang-int` with the value 2,147,483,647 gives +-2,147,483,648). + +.. _lang-arithmetic-typeconversion: + +If the operands are of different types, the "larger" type is used for +the calculation. If one of the numbers (operands) are of the type +**float** or of type **double**, floating point math will be used for +the calculation. + +.. note:: The specifics of these rules are beyond the scope of this + documentation; for more information, see `The C++ Programming + Language <http://www2.research.att.com/~bs/3rd.html>`_\ , by Bjarne + Stroustroup, Appendix C, especially §§C.4-C.6, or `this WikiBooks + entry on C++ type conversion + <http://en.wikibooks.org/wiki/C%2B%2B_Programming/Programming_Languages/C%2B%2B/Code/Statements/Variables/Type_Casting#Automatic_type_conversion>`_. + +.. note:: For more information on how computers represent integers, + see the Wikipedia page on `two's complement + <http://en.wikipedia.org/wiki/Two's_complement>`_. + +.. contents:: Contents + :local: + +Examples +-------- + + :: + + y = y + 3; + x = x - 7; + i = j * 6; + r = r / 5; + + +Syntax +------ + + :: + + result = value1 + value2; + result = value1 - value2; + result = value1 * value2; + result = value1 / value2; + + +Parameters +---------- + +**value1**: any numeric variable or constant + +**value2**: any numeric variable or constant + +Programming Tips +---------------- + +- Know that :ref:`integer constants <lang-constants-integers>` + default to :ref:`int <lang-int>`, so some constant calculations + may overflow (e.g., 200000 * 5000000 will yield a negative result). + +- Choose variable sizes that are large enough to hold the largest + results from your calculations. + +- Know at what point your variable will "roll over" and also what + happens in the other direction e.g. (0 - 1) for unsigned arithmetic, + or (0 - -2,147,483,648) for signed arithmetic. + +- For math that requires fractions, float variables may be used, but + be aware of their drawbacks: large size and slow computation speeds + (the STM32 has no floating point hardware, so all floating point + calculations have to be done in software). + +- Use cast operator, e.g. ``(int)myFloat`` to convert one variable type + to another on the fly. + +Arduino Compatibility +--------------------- + +Since the STM32 processor on the Maple is a 32-bit machine, the int +type overflows at a much higher value on Maple than on Arduino. In +particular, on Maple, ints do not overflow (become negative) until +they reach 2,147,483,648; on the Arduino, they overflow at 32,767. +Because of this, programs running on Maple are much less likely to run +into overflow issues. The following table summarizes the sizes and +ranges of integer datatypes on the Maple (the ranges of long long +types are approximate): + +.. _lang-arithmetic-int-sizes: + +.. csv-table:: + :header: Datatype, Unsigned range, Signed range, Size (bytes) + :widths: 8, 12, 17, 8 + + ``char``, 0 --- 255, -128 --- 127, 1 + ``short``, "0 --- 65,535", "-32,768 --- 32,767", 2 + ``int``, "0 --- 4,294,967,295", "-2,147,483,648 --- 2,147,483,647", 4 + ``long``, "0 --- 4,294,967,295", "-2,147,483,648 --- 2,147,483,647", 4 + ``long long``, "0 --- 1.8*10\ :sup:`19`\ " (approx.), "-9.2*10\ :sup:`18` --- 9.2*10\ :sup:`18` (approx.)", 8 + + +See Also +-------- + +- The individual sizes (in bits) of various available types are + defined in `libmaple_types.h + <http://github.com/leaflabs/libmaple/blob/master/libmaple/libmaple_types.h>`_\ + . + +- :ref:`sizeof <lang-sizeof>`\ () + + +.. include:: cc-attribution.txt diff --git a/docs/source/arduino/array.rst b/docs/source/lang/cpp/array.rst index f6bc141..30a818f 100644 --- a/docs/source/arduino/array.rst +++ b/docs/source/lang/cpp/array.rst @@ -1,6 +1,6 @@ .. highlight:: cpp -.. _arduino-array: +.. _lang-array: Arrays ====== @@ -10,6 +10,8 @@ number. Arrays in the C++ programming language, in which the Maple is programmed, can be complicated, but using simple arrays is relatively straightforward. +.. contents:: Contents + :local: Creating (Declaring) an Array ----------------------------- @@ -69,15 +71,15 @@ access is within legal bounds of the array size that you have declared. -To assign a value to an array: ------------------------------- +To assign a value to an array +----------------------------- :: mySensVals[0] = 10; -To retrieve a value from an array: ----------------------------------- +To retrieve a value from an array +--------------------------------- :: @@ -87,7 +89,7 @@ To retrieve a value from an array: Arrays and ``for`` Loops ------------------------ -Arrays are often manipulated inside :ref:`for loops <arduino-for>`, where +Arrays are often manipulated inside :ref:`for loops <lang-for>`, where the loop counter is used as the index for each array element. For example, to print the elements of an array over the serial port, you could do something like this:: @@ -106,9 +108,16 @@ Arduino `Knight Rider example <http://www.arduino.cc/en/Tutorial/KnightRider>`_\ (which will run unmodified on the Maple). +Arduino Compatibility +--------------------- + +Arrays on Maple are identical those on Arduino. See also -------- - :ref:`Storing arrays in FLASH memory <arm-gcc-attribute-flash>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/arduino/assignment.rst b/docs/source/lang/cpp/assignment.rst index 1c790bb..b6ad4d5 100644 --- a/docs/source/arduino/assignment.rst +++ b/docs/source/lang/cpp/assignment.rst @@ -1,14 +1,13 @@ .. highlight:: cpp -.. _arduino-assignment: +.. _lang-assignment: -= assignment operator (single equal sign) -========================================= +Assignment Operator (``=``) +=========================== Stores the value to the right of the equal sign in the variable to the left of the equal sign. - The single equal sign in the C++ programming language is called the assignment operator. It has a different meaning than in algebra class, where it indicated an equation or equality. The assignment @@ -36,13 +35,17 @@ needs to be able to hold the value stored in it. If it is not large enough to hold a value, the value stored in the variable will be incorrect. - - Don't confuse the assignment operator [ = ] (single equal sign) with the comparison operator [ == ] (double equal signs), which evaluates whether two expressions are equal. +Arduino Compatibility +--------------------- + +Assignments on the Maple are identical to those on Arduino. + + See Also -------- @@ -62,3 +65,6 @@ See Also `The Anatomy of the Assignment Operator <http://icu-project.org/docs/papers/cpp_report/the_anatomy_of_the_assignment_operator.html>`_ for more information. + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/bitshift.rst b/docs/source/lang/cpp/bitshift.rst new file mode 100644 index 0000000..e1c8de0 --- /dev/null +++ b/docs/source/lang/cpp/bitshift.rst @@ -0,0 +1,144 @@ +.. highlight:: cpp + +.. _lang-bitshift: + +Bit Shift Operators (``<<``, ``>>``) +==================================== + +(Adapted from `The Bit Math Tutorial +<http://www.arduino.cc/playground/Code/BitMath>`_ in `The Arduino +Playground <http://www.arduino.cc/playground/Main/HomePage>`_\ ) + +There are two bit shift operators in C++: the left shift operator +``<<`` and the right shift operator ``>>``. These operators cause the +bits in the left operand to be shifted left or right by the number of +positions specified by the right operand. + +More information on bitwise math can be obtained in the Wikipedia +article on `bitwise operations +<http://en.wikipedia.org/wiki/Bitwise_operation>`_\ , especially the +section on shifts in `C, C++, and Java +<http://en.wikipedia.org/wiki/Bitwise_operation#Shifts_in_C.2C_C.2B.2B.2C_C.23_and_Java>`_\ . + + +Syntax +------ + +``some_int << number_of_bits`` + +``some_int >> number_of_bits`` + + +Parameters +---------- + +* **some_int** An integer value or variable. + +* **number_of_bits** integer whose value is at most ``8 * + sizeof(variable)`` (so ``number_of_bits`` can be at most 32 for + ``int`` values, at most ``8`` for ``char`` values, etc.; the various + integer sizes are summarized :ref:`in this table + <lang-arithmetic-int-sizes>`\ ). + + + +Example: +-------- + +Here are some examples of bit shifting, with the binary representation of the number in comments:: + + int a = 5; // binary: 101 + int b = a << 3; // binary: 101000, or 40 in decimal + int c = b >> 3; // binary: 101, or back to 5 like we started with + + +When you left shift a value x by y bits (x << y), the leftmost y bits +in x are lost, literally shifted out of existence. We'll do this +example with ``char`` values (which are integers in the range 0-255, +and take up 8 bits of memory):: + + char a = 5; // binary (all 8 bits): 00000101 + char b = a << 7; // binary: 10000000 - the first 1 in 101 was discarded + + +If you are certain that none of the ones in a value are being shifted +into oblivion, a simple way to think of the left-shift operator is +that it multiplies the left operand by 2 raised to the right operand +power (in math notation, ``x << y`` equals x * 2\ :sup:`y`\ , as long +as none of the bits of x get shifted out). For example, to generate +powers of 2, the following expressions can be employed:: + + 1 << 0 == 1 + 1 << 1 == 2 + 1 << 2 == 4 + 1 << 3 == 8 + ... + 1 << 8 == 256 + 1 << 9 == 512 + 1 << 10 == 1024 + ... + +.. _lang-bitshift-signbit-gotcha: + +When you shift x right by y bits (``x >> y``), and the highest bit in +x is a 1, the behavior depends on the exact data type of x. If x is of +type ``int``, the highest bit is special, and determines whether x is +negative or not; the details are too complicated to explain here, but +they are thoroughly explained in the Wikipedia article on `two's +complement arithmetic +<http://en.wikipedia.org/wiki/Two%27s_complement>`_\ , which the +system most computers use to store integers. In that case, the sign +bit is copied into lower bits, for esoteric historical reasons:: + + int x = -16; // binary (all 32 bits): 11111111111111111111111111110000 + int y = x >> 3; // binary: 11111111111111111111111111111110 + + + +This behavior, called "sign extension", is often not what you +want. You probably wish zeros to be shifted in from the left. It +turns out that the right shift rules are different for ``unsigned +int`` values, so you can use a type cast to suppress ones being copied +from the left:: + + int x = -16; // binary: 11111111111111111111111111110000 + int y = (unsigned int)x >> 3; // binary: 00011111111111111111111111111110 + + + +If you are careful to avoid sign extension, you can use the +right-shift operator, ``>>``, as a way to divide by powers of 2. For +example:: + + int x = 1000; + int y = x >> 3; // integer division of 1000 by 8, causing y = 125. + + +Arduino Compatibility +--------------------- + +Since it's part of the C++ language, bit shifting on the Maple is +compatible with the Arduino; however, you should keep in mind that the +Maple has bigger integer types (as in, more bits) than the Arduino. + +Since the STM32 is a 32-bit processor, the ``int`` type takes up 32 +bits instead of 16, like on Arduino's 16-bit microcontroller. This +means that you can shift left, like ``x << y``, with bigger values of +``y`` on the Maple before ones in ``x`` start to get shifted out. + +To calculate the number of bits of an integer type on the Maple, +multiply its size in bytes (see :ref:`this table +<lang-arithmetic-int-sizes>` for these) by 8, since there are 8 +bits in 1 byte. For example, a ``short`` takes up 2 bytes of memory, +or 2 * 8 = 16 bits. + +See Also +-------- + +- :ref:`lang-bit` +- :ref:`lang-bitread` +- :ref:`lang-bitwrite` +- :ref:`lang-bitclear` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/bitwisemath.rst b/docs/source/lang/cpp/bitwisemath.rst new file mode 100644 index 0000000..28fe6bf --- /dev/null +++ b/docs/source/lang/cpp/bitwisemath.rst @@ -0,0 +1,186 @@ +.. highlight:: cpp + +.. _lang-bitwisemath: + +Bitwise Operators (``&``, ``|``, ``^``, ``~``) +============================================== + +The bitwise operators perform their calculations at the bit level of +variables. They help solve a wide range of common programming +problems. + +Much of the material here is adapted for Maple from an (Arduino) +`tutorial on bitwise math +<http://www.arduino.cc/playground/Code/BitMath>`_\ . Another great +resource is the Wikipedia article on `bitwise operations +<http://en.wikipedia.org/wiki/Bitwise_operation>`_\ . + +Below are descriptions and syntax for all of the operators. + +.. contents:: Contents + :local: + +.. _lang-bitwisemath-and: + +Bitwise AND (``&``) +------------------- + +The bitwise AND operator in C++ is a single ampersand, ``&``, used +between two other integer expressions. Bitwise AND operates on each +bit position of the surrounding expressions independently, according +to this rule: if both input bits are 1, the resulting output is 1, +otherwise the output is 0. Another way of expressing this is:: + + 0 0 1 1 operand1 + 0 1 0 1 operand2 + ---------- + 0 0 0 1 (operand1 & operand2) = result + + +On the Maple, the type ``int`` is a 32-bit value, so using ``&`` +between two ``int`` expressions causes 32 simultaneous AND operations +to occur. In a code fragment like:: + + int a = 92; // in binary: 00000000000000000000000001011100 + int b = 101; // in binary: 00000000000000000000000001100101 + int c = a & b; // result: 00000000000000000000000001000100, + // (or 68 in decimal). + + +Each of the 32 bits in ``a`` and ``b`` are processed using bitwise +AND, and all 32 resulting bits are stored in ``c``, resulting in the +value 1000100 in binary, which is 68 in decimal. + + +.. _lang-bitwisemath-or: + +Bitwise OR (``|``) +------------------ + +The bitwise OR operator in C++ is the vertical bar symbol, ``|``. Like +the ``&`` operator, ``|`` operates independently on each bit in its +two surrounding integer expressions, but what it does is +different. The bitwise OR of two bits is 1 if either or both of the +input bits is 1, otherwise it is 0. For example:: + + 0 0 1 1 operand1 + 0 1 0 1 operand2 + ---------- + 0 1 1 1 (operand1 | operand2) = result + +Here is an example of bitwise OR used in a snippet of C++ code (using +``char``, which takes up 8 bits of memory, instead of ``int``, which +uses 32):: + + char a = 92; // in binary: 01011100 + char b = 101; // in binary: 01100101 + char c = a | b; // result: 01111101, or 125 in decimal. + +.. _lang-bitwisemath-xor: + +Bitwise XOR (``^``) +------------------- + +There is a somewhat unusual operator in C++ called bitwise EXCLUSIVE +OR, also known as bitwise XOR. (In English, this is usually pronounced +"zor" or "ex-or"). The bitwise XOR operator is written using the caret +symbol, ``^``. This operator is very similar to the bitwise OR +operator ``|``, except it evaluates to 0 for a given bit position when +both of the input bits for that position are 1:: + + 0 0 1 1 operand1 + 0 1 0 1 operand2 + ---------- + 0 1 1 0 (operand1 ^ operand2) = result + + +Another way to look at bitwise XOR is that each bit in the result +is a 1 if the input bits are different, or 0 if they are the same. + +Here is a simple example:: + + int x = 12; // binary (ignoring extra bits): 1100 + int y = 10; // binary: 1010 + int z = x ^ y; // binary: 0110, or decimal 6 + + + +The ^ operator is often used to toggle (i.e. change from 0 to 1, or 1 +to 0) some of the bits in an integer expression. In a bitwise OR +operation if there is a 1 in the mask bit, that bit is inverted; if +there is a 0, the bit is not inverted and stays the same. Below is a +program to blink digital pin 13 (the LED pin on Maple):: + + // Blink Maple LED pin + + int led_pin = 13; + int toggle = 0; + + // demo for Exclusive OR + void setup(){ + pinMode(led_pin, OUTPUT); + } + + void loop(){ + toggle = toggle ^ 1; + digitalWrite(led_pin, toggle); + delay(100); + } + +.. _lang-bitwisemath-not: + +Bitwise NOT (``~``) +------------------- + +The bitwise NOT operator in C++ is the tilde character ``~``. Unlike +``&`` and ``|``, the bitwise NOT operator is applied to a single +operand to its right. Bitwise NOT changes each bit to its opposite: 0 +becomes 1, and 1 becomes 0. For example:: + + 0 1 operand1 + ---- + 1 0 ~operand1 = result + +Another example:: + + char a = 103; // binary: 01100111 + char b = ~a; // binary: 10011000 = -104 + +You might be surprised to see a negative number like -104 as the +result of this operation. This is because the highest bit in an int +variable is the so-called "sign bit". If the highest bit is 1, the +number is interpreted as negative. This encoding of positive and +negative numbers is referred to as *two's complement*. For more +information, see the Wikipedia article on `two's +complement. <http://en.wikipedia.org/wiki/Twos_complement>`_ + +As an aside, it is interesting to note that (under two's complement +arithmetic) for any integer ``x``, ``~x`` is the same as ``-x-1``. + +At times, the sign bit in a signed integer expression can cause +some unwanted surprises. + + +Uses +---- + +One of the most common uses of bitwise operations is to select or +manipulate a particular bit (or bits) from an integer value, often +called `bit masking +<http://en.wikipedia.org/wiki/Mask_%28computing%29>`_\ . See the +linked Wikipedia article for more information and examples. + +If you really want to see bit-twiddling techniques in their full +glory, you could do much worse than to get yourself a copy of +`Hacker's Delight <http://www.hackersdelight.org/>`_\ . + + +See Also +-------- + +- :ref:`Boolean operations <lang-boolean>` (``&&``, ``||``) +- :ref:`Compound bitwise operations <lang-compoundbitwise>` (``&=``, + ``|=``, ``^=``). + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/boolean.rst b/docs/source/lang/cpp/boolean.rst new file mode 100644 index 0000000..8d6aa5c --- /dev/null +++ b/docs/source/lang/cpp/boolean.rst @@ -0,0 +1,91 @@ +.. highlight:: cpp + +.. _lang-boolean: + +Boolean Operators +================= + +These can be used inside the condition of an :ref:`if <lang-if>` +statement. Evaluate to :ref:`true <lang-constants-true>` or +:ref:`false <lang-constants-false>`. + +.. contents:: Contents + :local: + +.. _lang-boolean-and: + +&& (logical and) +---------------- + +True only if both operands are true. For example:: + + if (digitalRead(2) == HIGH && digitalRead(3) == HIGH) { // read two switches + // ... + } + +is true only if both inputs are high. Another example:: + + if (a >= 10 && a <= 20){} // true if a is between 10 and 20 + +**Be careful** not to say ``10 <= a <= 20``! This won't work the way +you want. You have to separately test whether ``a`` is at least 10 +using ``a >= 10``, then test whether ``a`` is at most 20 using ``a <= +20``, then combine the results using ``&&``. + + +.. _lang-boolean-or: + +\|\| (logical or) +----------------- + +True if either operand is true. For example:: + + if (x > 0 || y > 0) { + // ... + } + +is true if either ``x`` or ``y`` is greater than 0. + +.. _lang-boolean-not: + +! (logical not) +--------------- + +True if the operand is false. For example:: + + if (!x) { + // ... + } + +is true if ``x`` is false (i.e. if ``x`` is zero). + +Some Advice +----------- + +.. warning:: + + Make sure you don't mistake the boolean AND operator ``&&`` + (double ampersand) for the :ref:`bitwise AND operator + <lang-bitwisemath-and>` ``&`` (single ampersand). They are + entirely different beasts. + + Similarly, do not confuse the boolean OR operator ``||`` (double + pipe) with the :ref:`bitwise OR operator <lang-bitwisemath-or>` + ``|`` (single pipe). + + The :ref:`bitwise NOT operator <lang-bitwisemath-not>` ``~`` + (tilde) looks much different than the boolean not operator ``!`` + (exclamation point, or "bang", as some programmers say), but you + still have to be sure which one you want. + + +See Also +-------- + +- :ref:`Bitwise operators <lang-bitwisemath>` (``&``, ``|``, ``^``, ``~``) +- :ref:`Compound bitwise operators <lang-compoundbitwise>` (``&=``, + ``|=``, ``^=``). +- :ref:`if statement <lang-if>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/booleanvariables.rst b/docs/source/lang/cpp/booleanvariables.rst new file mode 100644 index 0000000..6051b8c --- /dev/null +++ b/docs/source/lang/cpp/booleanvariables.rst @@ -0,0 +1,54 @@ +.. highlight:: cpp + +.. _lang-booleanvariables: + +Booleans +======== + +A **boolean** holds one of two values, :ref:`true +<lang-constants-true>` or :ref:`false <lang-constants-false>`. On a +Maple, each boolean variable has type ``bool``. + +.. warning:: + + On an Arduino, the type ``boolean`` is also provided. While the + Maple also has this type for compatibility, **its use is strongly + discouraged**. The ``bool`` type is a standard part of C++, while + ``boolean`` is a non-standard extension that serves no purpose. + +Example +------- + +:: + + int ledPin = 13; // LED on pin 13 + int switchPin = 12; // momentary switch on 12, other side connected to ground + + // running is a boolean variable: + bool running = false; + + void setup() { + pinMode(ledPin, OUTPUT); + pinMode(switchPin, INPUT); + digitalWrite(switchPin, HIGH); // turn on pullup resistor + } + + void loop() { + if (digitalRead(switchPin) == LOW) { + // switch is pressed - pullup keeps pin high normally + delay(100); // delay to debounce switch + running = !running; // toggle running variable + digitalWrite(ledPin, running) // indicate via LED + } + } + +See also +-------- + + +- :ref:`Boolean constants <lang-constants-bool>` +- :ref:`Boolean operators <lang-boolean>` +- :ref:`Variables <lang-variables>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/break.rst b/docs/source/lang/cpp/break.rst new file mode 100644 index 0000000..ce8ac17 --- /dev/null +++ b/docs/source/lang/cpp/break.rst @@ -0,0 +1,35 @@ +.. highlight:: cpp + +.. _lang-break: + +``break`` +========= + +``break`` is used to exit from a :ref:`while <lang-while>`\ , +:ref:`for <lang-for>`\ , or :ref:`do/while <lang-dowhile>` loop, +bypassing the normal loop condition. It is also used to exit from a +:ref:`switch <lang-switchcase>` statement. + + +Example +------- + +:: + + for (x = 0; x < 255; x ++) + { + digitalWrite(PWMpin, x); + sens = analogRead(sensorPin); + if (sens > threshold){ // bail out on sensor detect + x = 0; + // this line of code means that we'll immediately exit + // from the "for" loop: + break; + } + delay(50); + } + + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/built-in-types.rst b/docs/source/lang/cpp/built-in-types.rst new file mode 100644 index 0000000..1323db8 --- /dev/null +++ b/docs/source/lang/cpp/built-in-types.rst @@ -0,0 +1,95 @@ +.. highlight:: cpp + +.. _lang-built-in-types: + +================ + Built-in Types +================ + +This document serves as a reference for many of the built-in types +which are available when programming in the IDE. Programmers using +the :ref:`command-line tools <unix-toolchain>` will have access to +these types as long as they have imported `wirish.h +<https://github.com/leaflabs/libmaple/blob/master/wirish/wirish.h>`_; +several are defined in in `libmaple_types.h +<https://github.com/leaflabs/libmaple/blob/master/libmaple/libmaple_types.h>`_. + +.. _lang-built-in-types-integral: + +Integral types +-------------- + +.. cpp:type:: char + + 8-bit integer value. + +.. cpp:type:: short + + 16-bit integer value. + +.. cpp:type:: int + + 32-bit integer value. + +.. cpp:type:: long + + 64-bit integer value. + +.. cpp:type:: long long + + 64-bit integer value. + +.. cpp:type:: int8 + + Synonym for ``char``. + +.. cpp:type:: uint8 + + Synonym for ``unsigned char``. + +.. cpp:type:: int16 + + Synonym for ``short``. + +.. cpp:type:: uint16 + + Synonym for ``unsigned short``. + +.. cpp:type:: int32 + + Synonym for ``int``. + +.. cpp:type:: uint32 + + Synonym for ``unsigned int`` + +.. cpp:type:: int64 + + Synonym for ``long long`` + +.. cpp:type:: uint64 + + Synonym for ``unsigned long long``. + +Floating-Point Types +-------------------- + +.. cpp:type:: float + + 32-bit, IEEE 754 single-precision floating-point type. + +.. cpp:type:: double + + 64-bit, IEEE 754 double-precision floating-point type. + +Other Types +----------- + +.. cpp:type:: voidFuncPtr + + Pointer to a function that takes no arguments and returns nothing, i.e. + + :: + + typedef void (*voidFuncPtr)(void); + diff --git a/docs/source/lang/cpp/byte.rst b/docs/source/lang/cpp/byte.rst new file mode 100644 index 0000000..45c9d5f --- /dev/null +++ b/docs/source/lang/cpp/byte.rst @@ -0,0 +1,34 @@ +.. highlight:: cpp + +.. _lang-byte: + +byte +==== + +The ``byte`` type stores a 1-byte (8-bit) unsigned integer number, +from 0 to 255. + +.. warning:: + + The ``byte`` type is provided for compatibility with Arduino. + However, it is a non-standard extension. The standard C++ type for + storing an 8-bit unsigned integer is ``unsigned char``; we + recommend using that instead. (Your code will still work on an + Arduino). + + +Example +------- + +:: + + byte b = 134; + +See Also +-------- + +- :ref:`byte() <lang-bytecast>` (casting a value to a byte) +- :ref:`Variables <lang-variables>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/bytecast.rst b/docs/source/lang/cpp/bytecast.rst new file mode 100644 index 0000000..b3f0de2 --- /dev/null +++ b/docs/source/lang/cpp/bytecast.rst @@ -0,0 +1,50 @@ +.. highlight:: cpp + +.. _lang-bytecast: + +byte() (cast) +============= + +Converts a value to the :ref:`byte <lang-byte>` data type. + +.. note:: + + Casting to the byte type is provided for compatibility with + Arduino. However, the recommended Maple type for storing an 8-bit + unsigned integer is ``uint8``. (C and C++ programmers: ``stdint.h`` + is also available). + + In order to cast a variable ``x`` to a ``uint8``, the + following syntax can be used:: + + uint8(x); + +Syntax +------ + +``byte(x)`` + + +Parameters +---------- + +**x**: a value of any integer type + + +Returns +------- + +The value, converted to a ``byte``. Note, however, that if the value +is larger than the maximum value you can store in a byte (255), then +the results might be strange and unexpected. + + +See Also +-------- + +- :ref:`lang-byte` + + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/cc-attribution.txt b/docs/source/lang/cpp/cc-attribution.txt new file mode 100644 index 0000000..e100140 --- /dev/null +++ b/docs/source/lang/cpp/cc-attribution.txt @@ -0,0 +1,9 @@ +.. Included in all this directory's files in order to satisfy the +.. Arduino CC Attribution-ShareAlike 3.0 License + +.. admonition:: License and Attribution + + This documentation page was adapted from the `Arduino Reference + Documentation <http://arduino.cc/en/Reference/HomePage>`_\ , which + is released under a `Creative Commons Attribution-ShareAlike 3.0 + License <http://creativecommons.org/licenses/by-sa/3.0/>`_. diff --git a/docs/source/lang/cpp/char.rst b/docs/source/lang/cpp/char.rst new file mode 100644 index 0000000..b8747f3 --- /dev/null +++ b/docs/source/lang/cpp/char.rst @@ -0,0 +1,50 @@ +.. highlight:: cpp + +.. _lang-char: + +``char`` +======== + +The ``char`` type stores a 1-byte character value (or integer with +value from -128 to 127). Character literals are written in single +quotes, like this: ``'A'`` (for multiple characters - strings - use +double quotes: ``"ABC"``). + + +Just like everything else on a computer, characters are stored as +numbers. You can see the specific encoding in the `ASCII chart +<http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters>`_\ +. This means that it is possible to do arithmetic on characters, in +which the ASCII value of the character is used (e.g. ``'A' + 1`` has the +decimal value 66, since the ASCII value of the capital letter A in +decimal is 65). See the :ref:`Serial.println() +<lang-serial-println>` documentation for more information about how +characters are converted into numbers. + +The ``char`` datatype is a signed type, meaning that it encodes +numbers from -128 to 127. For an unsigned type, which stores values +from 0 to 255, just use the type ``unsigned char`` (two words). + + +Example +------- + +:: + + // the following two lines are equivalent, using the ASCII + // character encoding: + char c = 'A'; + char c = 65; + + +See also +-------- + + +- :ref:`lang-int` +- :ref:`lang-array` (a string is just an array of ``char``\ s) +- :ref:`Serial.println() <lang-serial-println>` + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/charcast.rst b/docs/source/lang/cpp/charcast.rst new file mode 100644 index 0000000..a480dec --- /dev/null +++ b/docs/source/lang/cpp/charcast.rst @@ -0,0 +1,36 @@ +.. highlight:: cpp + +.. _lang-charcast: + +``char()`` (cast) +================= + +Converts a value to the :ref:`char <lang-char>` data type. + +Syntax +------ + +``char(x)`` + + +Parameters +---------- + +**x**: a value of any type + + +Returns +------- + +The value, converted to a ``char``. Note, however, that if the value +is outside the range of a ``char`` (-128 to 127), then the results +might be strange and unexpected. + + +See Also +-------- + +- :ref:`char <lang-char>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/comments.rst b/docs/source/lang/cpp/comments.rst new file mode 100644 index 0000000..c5f118a --- /dev/null +++ b/docs/source/lang/cpp/comments.rst @@ -0,0 +1,67 @@ +.. highlight:: cpp + +.. _lang-comments: + +Comments +======== + +Comments are lines in the program that are used to inform yourself or +others about the way the program works. They are ignored by the +compiler, and not exported to the processor, so they don't take up any +space in RAM or Flash. + +One use for comments is to help you understand (or remember) how your +program works, or to inform others how your program works. There are +two different ways of making comments. + +.. _lang-comments-singleline: + +**Single line comment**: Anything following two slashes, ``//``, until +the end of the line, is a comment:: + + x = 5; // the rest of this line is a comment + +.. _lang-comments-multiline: + +**Multi-line comment**: Anything in between a pair of ``/*`` and ``*/`` +is a comment:: + + /* <-- a slash-star begins a multi-line comment + + all of this in the multi-line comment - you can use it to comment + out whole blocks of code + + if (gwb == 0){ // single line comment is OK inside a multi-line comment + x = 3; + } + + // don't forget the "closing" star-slash - they have to be balanced: + */ + +Note that it's okay to use single-line comments within a multi-line +comment, but you can't use multi-line comments within a multi-line +comment. Here's an example:: + + /* ok, i started a multi-line comment + + x = 3; /* this next star-slash ENDS the multi-line comment: */ + + x = 4; // this line is outside of the multi-line comment + + // next line is also outside of the comment, and causes a compile error: + */ + +Programming Tip +--------------- + +When experimenting with code, "commenting out" parts of your program +is a convenient way to remove lines that may be buggy. This leaves +the lines in the code, but turns them into comments, so the compiler +just ignores them. This can be especially useful when trying to locate +a problem, or when a program refuses to compile and the compiler error +is cryptic or unhelpful. + + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/comparison.rst b/docs/source/lang/cpp/comparison.rst new file mode 100644 index 0000000..b24355f --- /dev/null +++ b/docs/source/lang/cpp/comparison.rst @@ -0,0 +1,87 @@ +.. highlight:: cpp + +.. _lang-comparison: + +Comparison Operators (``==``, ``!=``, ``<``, ``>``, ``<=``, ``>=``) +=================================================================== + +The comparison operators ``==``, ``!=``, ``<``, ``>``, ``<=``, and +``>=`` are used to compare two numbers. They are :ref:`true +<lang-constants-true>` when the comparison is true, and :ref:`false +<lang-constants-false>` otherwise. They are based on the symbols +=, ≠, <, >, ≤, and ≥ from mathematics. + +Here are some examples, with their meaning in comments:: + + // "eq" is true when x is equal to y + bool eq = (x == y); + + // "neq" is true when x is different than y + bool neq = (x != y); + + // "lt" is true when x is less than, but NOT equal to, y + bool lt = (x < y); + + // "gt" is true when x is greater than, but NOT equal to, y + bool gt = (x > y); + + // "lte" is true when x is less than or equal to y + bool lte = (x <= y); + + // "gte" is true when x is greater than or equal to y + bool gte = (x >= y); + +The parentheses are optional; they are present only for clarity. For +example, the following two lines are the same:: + + bool eq = x == y; + + bool eq = (x == y); + +Uses +---- + +Comparison operators, along with :ref:`boolean operators +<lang-boolean>`, are useful inside the conditionals of :ref:`if +<lang-if>` statements. Here's one example:: + + if (x < 50) { + // only execute these lines if x is less than 50 + SerialUSB.println("delaying:"); + SerialUSB.println(x); + delay(x); + } + +.. warning:: + Beware of accidentally using the single equal sign (``=``) when you + meant to test if two numbers are equal (``==``). This is a common + mistake inside of ``if`` statement conditionals, e.g.:: + + // DON'T MAKE THIS MISTAKE + if (x = 10) { + // body + } + + The single equal sign is the assignment operator, and sets x to 10 + (puts the value 10 into the variable x). Instead use the double equal + sign (e.g. ``if (x == 10)``), which is the comparison operator, and + tests *whether* x is equal to 10 or not. The latter statement is only + true if x equals 10, but the former statement will always be true. + + This is because C evaluates the statement ``if (x=10)`` as follows: 10 + is assigned to x (remember that the single equal sign is the + :ref:`assignment operator <lang-assignment>`), so x now + contains 10. Then the 'if' conditional evaluates 10, which evaluates + to :ref:`true <lang-constants-true>`, since any non-zero number + evaluates to ``true``. + + Consequently, the conditional of an ``if`` statement like ``if (x = + 10) {...}`` will always evaluate to ``true``, and the variable x + will be set to 10, which is probably not what you meant. + + (This sometimes has uses, though, so just because an assignment + appears within a conditional doesn't mean it's automatically wrong. + Be careful to know what you mean.) + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/compoundarithmetic.rst b/docs/source/lang/cpp/compoundarithmetic.rst new file mode 100644 index 0000000..420f1db --- /dev/null +++ b/docs/source/lang/cpp/compoundarithmetic.rst @@ -0,0 +1,44 @@ +.. highlight:: cpp + +.. _lang-compoundarithmetic: + +Compound Arithmetic Operators (``+=`` , ``-=``, ``*=``, ``/=``) +=============================================================== + +These oparators perform a mathematical operation on a variable with +another constant or variable. These operators are just a convenient +shorthand:: + + x += y; // equivalent to the expression x = x + y; + x -= y; // equivalent to the expression x = x - y; + x *= y; // equivalent to the expression x = x * y; + x /= y; // equivalent to the expression x = x / y; + +Here is an example:: + + int x = 2; + int y = 10; + + x += 4; // x now contains 6 + x -= 3; // x now contains 3 + x *= y; // x now contains 30 + x /= 2; // x now contains 15 + x += max(20, 6); // x now contains 35 + x -= sq(5); // x now contains 15 + +Parameters +---------- + +**x**: a numeric variable + +**y**: a numeric variable, number constant, or any other expression +that evaluates to a number (e.g. call to a function that returns a +number). + +See Also +-------- + +- :ref:`Arithmetic operators <lang-arithmetic>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/compoundbitwise.rst b/docs/source/lang/cpp/compoundbitwise.rst new file mode 100644 index 0000000..a4bbb24 --- /dev/null +++ b/docs/source/lang/cpp/compoundbitwise.rst @@ -0,0 +1,231 @@ +.. highlight:: cpp + +.. _lang-compoundbitwise: + +Compound Bitwise Operators (``&=``, ``|=``, ``^=``) +=================================================== + +The compound bitwise operators perform their calculations at the +bit level of variables. They are often used to clear and set +specific bits of a variable. + +See the :ref:`bitwise math tutorial <lang-bitwisemath>` for more +information on bitwise operators. + +.. contents:: Contents + :local: + +.. _lang-compoundbitwise-and: + +Compound bitwise AND (``&=``) +----------------------------- + +The compound bitwise AND operator ``&=`` is often used with a variable +and a constant to force particular bits in a variable to be zero. This +is often referred to in programming guides as "clearing" or +"resetting" bits. In a program, writing the line ``x &= y;`` is +equivalent to writing ``x = x & y;``. That is, the value of ``x`` +after the line will be equal to its old value bitwise ANDed with the +value of ``y``:: + + x &= y; // equivalent to x = x & y; + +You can use any integer variable for ``x`` (i.e., any variable of type +``int``, ``long``, ``char``, ``byte``, etc.). You can use either an +integer variable or any :ref:`integer value +<lang-constants-integers>` (like ``3`` or ``0x20``) for ``y``. + +Before doing an example of ``&=``, let's first review the Bitwise AND +(``&``) operator:: + + 0 0 1 1 operand1 + 0 1 0 1 operand2 + ---------- + 0 0 0 1 (operand1 & operand2) = result + +As shown above, bits that are "bitwise ANDed" with 0 become 0, while +bits that are "bitwise ANDed" with 1 are left unchanged. So, if ``b`` +is a ``byte`` variable, then ``b & B00000000`` equals zero, and ``b & +B11111111`` equals ``b``. + +.. _lang-compoundbitwise-binconst: + +.. note:: The above uses :ref:`binary constants + <lang-constants-integers-bin>`\ . The numbers are still the same + value in other representations, they just might not be as easy to + understand. + + Normally, in C and C++ code, :ref:`hexadecimal + <lang-constants-integers-hex>` or :ref:`octal + <lang-constants-integers-oct>` are used when we're interested in + an integer's bits, rather than its value as a number. + + While hexadecimal and octal literals might be harder to understand + at first, you should really take the time to learn them. They're + part of C, C++, and many other programming languages, while binary + constants are available only for compatibility with Arduino. + + Also, ``B00000000`` is shown for clarity, but zero in any number + format is zero. + +So, to clear (set to zero) bits 0 and 1 of a one-byte variable, while +leaving the rest of the variable's bits unchanged, use the compound +bitwise AND operator ``&=`` with the constant ``B11111100`` +(hexadecimal ``0xFC``\ ):: + + 1 0 1 0 1 0 1 0 variable + 1 1 1 1 1 1 0 0 mask + ---------------------- + 1 0 1 0 1 0 0 0 + ^^^^^^^^^^^^^^^^ ^^^^ + unchanged cleared + + +Here is the same representation with the variable's bits replaced +with the symbol ``x``\ :: + + x x x x x x x x variable + 1 1 1 1 1 1 0 0 mask + ---------------------- + x x x x x x 0 0 + ^^^^^^^^^^^^^^^^ ^^^^ + unchanged cleared + + +So, using a byte variable ``b``\ , if we say:: + + b = B10101010; // B10101010 == 0xAA + b &= B11111100; // B11111100 == 0xFC + +then we will have :: + + b == B10101000; // B10101000 == 0xA8 + +.. _lang-compoundbitwise-or: + +Compound bitwise OR (``|=``) +---------------------------- + +The compound bitwise OR operator ``|=`` is often used with a variable +and a constant to "set" (set to 1) particular bits in a variable. In +a program, writing the line ``x |= y;`` is equivalent to writing ``x = +x | y;``. That is, the value of ``x`` after the line will be equal to +its old value bitwise ORed with the value of ``y``:: + + x |= y; // equivalent to x = x | y; + +You can use any integer variable for ``x`` (i.e., any variable of type +``int``, ``long``, ``char``, ``byte``, etc.). You can use either an +integer variable or any integer value (like ``3`` or ``0x20``) for +``y``. (This works the same way as :ref:`compound bitwise AND +<lang-compoundbitwise-and>`\ , ``&=``). + +Before doing an example of ``|=``, let's first review the Bitwise OR +(``|``) operator:: + + 0 0 1 1 operand1 + 0 1 0 1 operand2 + ---------- + 0 1 1 1 (operand1 | operand2) = result + +Bits that are "bitwise ORed" with 0 are unchanged, while bits that are +"bitwise ORed" with 1 are set to 1. So if ``b`` is a ``byte`` +variable, then ``b | B00000000`` equals ``b``, and ``b & B11111111`` +equals ``B11111111`` (here we've used binary constants; see the +:ref:`note <lang-compoundbitwise-binconst>` above). + +So, to set bits 0 and 1 of a one-byte variable, while leaving the rest +of the variable unchanged, use the compound bitwise OR operator +(``|=``) with the constant ``B00000011`` (hexadecimal ``0x3``):: + + 1 0 1 0 1 0 1 0 variable + 0 0 0 0 0 0 1 1 mask + ---------------------- + 1 0 1 0 1 0 1 1 + ^^^^^^^^^^^^^^^^ ^^^^ + unchanged set + +Here is the same representation with the variable's bits replaced with +the symbol ``x``:: + + x x x x x x x x variable + 0 0 0 0 0 0 1 1 mask + ---------------------- + x x x x x x 1 1 + ^^^^^^^^^^^^^^^^ ^^^^ + unchanged set + +So, using a byte variable ``b``, if we say:: + + b = B10101010; // B10101010 == 0xAA + b |= B00000011; // B00000011 == 0x3 + +then we will have :: + + b == B10101011; // B10101011 == 0xAB + +.. _lang-compoundbitwise-xor: + +Compound bitwise XOR (``^=``) +----------------------------- + +The compound bitwise XOR operator ``^=`` is used with a variable and a +constant to "toggle" (change 0 to 1, and 1 to 0) particular bits in a +variable. In a program, writing the line ``x ^= y;`` is equivalent to +writing ``x = x ^ y;``. That is, the value of ``x`` after the line +will be equal to its old value bitwise XORed with the value of ``y``:: + + x ^= y; // equivalent to x = x ^ y; + +You can use any integer variable for ``x`` (i.e., any variable of type +``int``, ``long``, ``char``, ``byte``, etc.). You can use either an +integer variable or any integer value (like ``3`` or ``0x20``) for +``y``. (This works the same way as :ref:`&= +<lang-compoundbitwise-and>` and :ref:`\|= +<lang-compoundbitwise-or>`; in fact, these three operators all +work the same in this way). + +Before doing an example of ``^=``, let's first review the Bitwise +XOR operator, ``^``:: + + 0 0 1 1 operand1 + 0 1 0 1 operand2 + ---------- + 0 1 1 0 (operand1 ^ operand2) = result + +One way to look at bitwise XOR is that each bit in the result is a 1 +if the input bits are different, or 0 if they are the same. Another +way to think about it is that the result bit will be 1 when *exactly* +one (no more, no less) of the input bits is 1; otherwise, it will be +zero. This means that if you XOR a bit with 1, it will change (or +toggle) its value, while if you XOR a bit with 0, it stays the same. + +So, to toggle bits 0 and 1 of a one-byte variable, while leaving the +rest of the variable unchanged, use the compound bitwise XOR operator +``^=`` with the constant ``B00000011`` (hexadecimal ``0x3``\ ; see +:ref:`note <lang-compoundbitwise-binconst>` above):: + + 1 0 1 0 1 0 1 0 variable + 0 0 0 0 0 0 1 1 mask + ---------------------- + 1 0 1 0 1 0 1 1 + ^^^^^^^^^^^^^^^^ ^^^^ + unchanged toggled + +So, using a byte variable ``b``, if we say:: + + b = B10101010; // B10101010 == 0xAA + b ^= B00000011; // B00000011 == 0x3 + +then we will have :: + + b == B10101001; // B10101001 == 0xA9 + +See Also +-------- + +- :ref:`Boolean operations <lang-boolean>` (``&&``, ``||``) +- :ref:`Bitwise operators <lang-bitwisemath>` (``&``, ``|``, ``^``, ``~``) + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/const.rst b/docs/source/lang/cpp/const.rst new file mode 100644 index 0000000..52de85f --- /dev/null +++ b/docs/source/lang/cpp/const.rst @@ -0,0 +1,52 @@ +.. highlight:: cpp + +.. _lang-const: + +``const`` +========= + +The ``const`` keyword stands for "constant". It is a variable +*qualifier* that modifies the behavior of the variable, making a +variable "*read-only*". This means that the variable can be used just +as any other variable of its type, but its value cannot be +changed. You will get a compiler error if you try to assign a value to +a ``const`` variable. + +Constants defined with the ``const`` keyword obey the same rules of +:ref:`variable scoping <lang-scope>` that govern other +variables. This, and the pitfalls of using :ref:`#define +<lang-define>`, often makes using the ``const`` keyword a superior +method for defining constants than ``#define``. + +Example +------- + +:: + + // this defines a variable called "pi", which cannot be changed: + const float pi = 3.14; + float x; + + // .... + + x = pi * 2; // it's fine to find the value of a const variable + + pi = 7; // illegal - you can't write to (modify) a constant + + +**#define** or **const** +------------------------ + +You can use either ``const`` or ``#define`` for creating numeric or +string constants. For :ref:`arrays <lang-array>`\ , you will need +to use ``const``. In general, ``const`` is preferred over ``#define`` +for defining constants. + +See Also +-------- + +- :ref:`#define <lang-define>` +- :ref:`volatile <lang-volatile>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/continue.rst b/docs/source/lang/cpp/continue.rst new file mode 100644 index 0000000..13d1815 --- /dev/null +++ b/docs/source/lang/cpp/continue.rst @@ -0,0 +1,32 @@ +.. highlight:: cpp + +.. _lang-continue: + +``continue`` +============ + +The ``continue`` keyword skips the rest of the current iteration of a +:ref:`while <lang-while>`\ , :ref:`for <lang-for>`\ , or +:ref:`do/while <lang-dowhile>` loop. It continues by checking the +conditional expression of the loop, and proceeding with any subsequent +iterations. + +Example +------- + +:: + + + for (x = 0; x < 255; x ++) { + if (x > 40 && x < 120) { // create jump in values + continue; // skips the next two lines and goes to the + // beginning of the loop, with the next value of x + } + + digitalWrite(PWMpin, x); + delay(50); + } + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/curly-braces.rst b/docs/source/lang/cpp/curly-braces.rst new file mode 100644 index 0000000..a4bd3dc --- /dev/null +++ b/docs/source/lang/cpp/curly-braces.rst @@ -0,0 +1,109 @@ +.. highlight:: cpp + +.. _lang-curly-braces: + +Curly Braces (``{``, ``}``) +=========================== + +.. contents:: Contents + :local: + +Introduction +------------ + +Curly braces (also referred to as just "braces" or as "curly +brackets") are a major part of the C and C++ programming +languages. They are used in several different constructs, outlined +below, and this can sometimes be confusing for beginners. + +An opening curly brace, ``{`` must always be followed by a closing +curly brace ``}``. This is a condition that is often referred to as +the braces being *balanced*. The Maple IDE (integrated development +environment) includes a convenient feature to check the balance of +curly braces. Just select a brace, or even click the insertion point +immediately following a brace, and its companion will be highlighted\ +[#fbug]_\ . + +Beginning programmers, and programmers coming to C++ from languages +without braces, often find using them confusing or daunting. + +Because the use of the curly brace is so varied, it is good +programming practice to type the closing brace immediately after +typing the opening brace when inserting a construct which requires +curly braces. Then insert some blank lines between your braces and +begin inserting statements. Your braces, and your attitude, will never +become unbalanced. + +Unbalanced braces can often lead to cryptic, impenetrable compiler +errors that can sometimes be hard to track down in a large program. +Because of their varied usages, braces are also incredibly important +to the syntax of a program and moving a brace one or two lines will +usually dramatically affect the meaning of a program. + +The main uses of curly braces +----------------------------- + +**Functions**:: + + // a function body needs braces around it + void myFunction(datatype argument) { + // ... function body goes in here ... + } + +**Loops** (see the :ref:`while <lang-while>`\ , :ref:`for +<lang-for>`\ , and :ref:`do/while <lang-dowhile>` loop reference +pages for more information):: + + // you should put braces around the body of a loop: + + while (boolean expression) { + // code inside the loop goes here + } + + for (initialisation; termination condition; incrementing expr) { + // code inside the loop goes here + } + + do { + // code inside the loop goes here + } while (boolean expression); + + +**Conditional statements** (see the :ref:`if statement <lang-if>` +reference page for more information):: + + // you should put braces around the body of an "if", "else if", + // or "else": + + if (boolean expression) { + // code inside the "if" + } + else if (boolean expression) { + // code inside the "else if" + } + else { + // code inside the "else" + } + +**Switch statements** (see the :ref:`switch statement +<lang-switchcase>` reference page for more information):: + + switch (var) { + case 1: + doThing1(); + break; + case 2: + doThing2(); + break; + } + +.. rubric:: Footnotes + +.. TODO remove this once IDE 0.1.0 released + +.. [#fbug] At present this feature is slightly buggy as the IDE will + often find (incorrectly) a brace in text that has been commented + out. + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/define.rst b/docs/source/lang/cpp/define.rst new file mode 100644 index 0000000..677390d --- /dev/null +++ b/docs/source/lang/cpp/define.rst @@ -0,0 +1,56 @@ +.. highlight:: cpp + +.. _lang-define: + +``#define`` +=========== + +``#define`` is a useful C and C++ feature that allows the programmer +to give a name to a constant value before the program is compiled. +The compiler will replace references to these constants with the +defined value at compile time. + +This can have some unwanted side effects. In general, the :ref:`const +<lang-const>` keyword is preferred for defining constants. + + +Syntax +------ + +The following line would define the name ``MY_CONSTANT`` to have value +``value``:: + + #define MY_CONSTANT value + +Note that the ``#`` is necessary. It is usually good style for the +name to be capitalized, although this is not required. + +There is no semicolon after the #define statement. If you include one, +the compiler will likely throw cryptic errors in unrelated places. +That is, **don't do this**:: + + // DON'T DO THIS! THE SEMICOLON SHOULDN'T BE THERE! + #define NAME value; + +Similarly, including an equal sign after the ``#define`` line will +also generate a cryptic compiler error further down the page. That +is, **don't do this, either**:: + + // DON'T DO THIS, EITHER! THE EQUALS SIGN SHOULDN'T BE THERE! + #define NAME = value + +Example +------- + +:: + + #define LED_PIN 13 + // The compiler will replace any mention of LED_PIN with + // the value 3 at compile time. + +See Also +-------- +- :ref:`const <lang-const>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/double.rst b/docs/source/lang/cpp/double.rst new file mode 100644 index 0000000..1527778 --- /dev/null +++ b/docs/source/lang/cpp/double.rst @@ -0,0 +1,48 @@ +.. _lang-double: + +``double`` +========== + +Double precision floating point type. Occupies 8 bytes. On Maple, the +``double`` type has a range of approximately -1.79769×10^308 to +1.79769×10^308; the ``double`` type subject to the same :ref:`overflow +issues <lang-variables-rollover>` as any numeric data type. + +Floating point numbers are not exact, and may yield strange results +when compared. For example ``6.0 / 3.0`` may not equal ``2.0``. You +should instead check that the absolute value of the difference between +the numbers is less than some small number. + +Floating point math is also much slower than integer math in +performing calculations, so should be avoided if, for example, a loop +has to run at top speed for a critical timing function. Programmers +often go to some lengths to convert floating point calculations to +integer math to increase speed. + +For more information, see the `Wikipedia article on floating point +math <http://en.wikipedia.org/wiki/Floating_point>`_\ . + +Floating-point numbers represent numbers with "decimal point", unlike +integral types, which always represent whole numbers. Floating-point +numbers are often used to approximate analog and continuous values +because they have greater resolution than integers. + +The double implementation on the Maple uses twice the number of bytes +as a :ref:`float <lang-float>`, with the corresponding gains in +precision. + +Tip +--- + +Users who borrow code from other sources that includes ``double`` +variables may wish to examine the code to see if the implied range and +precision are different from that actually achieved on the Maple. + +See Also +-------- + +- :ref:`float <lang-float>` + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/doublecast.rst b/docs/source/lang/cpp/doublecast.rst new file mode 100644 index 0000000..511fe24 --- /dev/null +++ b/docs/source/lang/cpp/doublecast.rst @@ -0,0 +1,27 @@ +.. highlight:: cpp + +.. _lang-doublecast: + +``double()`` (cast) +=================== + +Converts a value to the :ref:`double <lang-double>` floating point +data type. Here is an example:: + + int x = 2; + double d = double(x); // d now holds 2.0, a double value + +The value ``x`` can be of any type. However, if ``x`` is not a number +(like an ``int`` or ``long``), you will get strange results. + +See the :ref:`double <lang-double>` reference for details about the +precision and limitations of ``double`` values on the Maple. + +See Also +-------- + +- :ref:`double <lang-double>` +- :ref:`float <lang-float>` +- :ref:`float() <lang-floatcast>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/dowhile.rst b/docs/source/lang/cpp/dowhile.rst new file mode 100644 index 0000000..fe92226 --- /dev/null +++ b/docs/source/lang/cpp/dowhile.rst @@ -0,0 +1,27 @@ +.. highlight:: cpp + +.. _lang-dowhile: + +``do``/``while`` +================ + +A ``do`` loop works in the same manner as a :ref:`while +<lang-while>` loop, with the exception that the condition is tested +at the end of the loop, so the ``do`` loop will *always* run at least +once. + +This is the basic syntax:: + + do { + // statement block + } while (test condition); + +Example:: + + do { + delay(50); // wait for sensors to stabilize + x = readSensors(); // check the sensors + } while (x < 100); + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/enum.rst b/docs/source/lang/cpp/enum.rst new file mode 100644 index 0000000..ba82383 --- /dev/null +++ b/docs/source/lang/cpp/enum.rst @@ -0,0 +1,53 @@ +.. highlight:: cpp + +.. _lang-enum: + +``enum`` +======== + +The ``enum`` keyword is used to specify an enumeration type. An +enumeration type is a type whose values are taken from a specified, +fixed list of constant values. + +Example +------- + +Here's an example defining an enumeration type called ``weather``, +which has values ``HOT``, ``COMFY``, and ``COLD``:: + + enum weather {HOT, COMFY, COLD}; + +Once you've defined this type, you can create variables of type +``weather``, in the same way you would with an :ref:`int <lang-int>` +or a :ref:`long <lang-long>`:: + + // create a weather variable named theWeather, with value COMFY: + weather theWeather = COMFY; + +Enumeration types are useful within :ref:`switch statements +<lang-switchcase>`. If you know that an argument is of an enumeration +type, you can make ``case`` statements for all of that type's possible +values, so you know you won't miss anything:: + + void describeWeather(weather currentWeather) { + switch(currentWeather) { + case HOT: + SerialUSB.println("it's hot out"); + break; + case COMFY: + SerialUSB.println("it's nice today"); + break; + case COLD: + SerialUSB.println("it's freezing!"); + break; + } + } + +Such a ``switch`` statement would need no :ref:`default +<lang-switchcase-default>`, since we know that ``currentWeather`` must +be either ``HOT``, ``COMFY``, or ``COLD``. + +See Also +-------- + +- :ref:`lang-switchcase` diff --git a/docs/source/lang/cpp/float.rst b/docs/source/lang/cpp/float.rst new file mode 100644 index 0000000..6937c8c --- /dev/null +++ b/docs/source/lang/cpp/float.rst @@ -0,0 +1,50 @@ +.. highlight:: cpp + +.. _lang-float: + +``float`` +========= + +Single-precision floating point number. Occupies 4 bytes. On Maple, +the ``float`` type has a range of approximately -3.40282×10^38 to +3.40282×10^38; the ``float`` type is subject to the same +:ref:`overflow issues <lang-variables-rollover>` as any numeric data +type. + +``float``\ s have only 6-7 decimal digits of precision. That means the +total number of digits, not the number to the right of the decimal +point. You can get more precision by using a :ref:`double +<lang-double>` (which has a precision of about 16 decimal digits). + +The following example declares a ``float`` value named ``myfloat``:: + + float myfloat; + +This example declares a ``float`` value named ``sensorCalibrate``, +with value 1.117:: + + float sensorCalibrate = 1.117; + +The general syntax for declaring a float named ``var`` with value +``val`` is:: + + float var = val; + +Here is a more extended example involving a :ref:`float cast +<lang-floatcast>`:: + + int x; + int y; + float z; + + x = 1; + y = x / 2; // y now contains 0, ints can't hold fractions + z = float(x) / 2; // z now contains .5 + +See Also +-------- + +- :ref:`double <lang-double>` +- :ref:`Variables <lang-variables>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/floatcast.rst b/docs/source/lang/cpp/floatcast.rst new file mode 100644 index 0000000..4766478 --- /dev/null +++ b/docs/source/lang/cpp/floatcast.rst @@ -0,0 +1,28 @@ +.. highlight:: cpp + +.. _lang-floatcast: + +``float()`` (cast) +================== + +Converts a value to the :ref:`float <lang-float>` data type. Here is +an example (see the :ref:`constants reference <lang-constants-fp>` for +an explanation of the "2.0f"):: + + int x = 2; + float f = float(x); // f now holds 2.0f, a float value + +The value ``x`` can be of any type. However, if ``x`` is not a number +(like an ``int``), you will get strange results. + +See the :ref:`float <lang-float>` reference for details about the +precision and limitations of ``float`` values on the Maple. + +See Also +-------- + +- :ref:`float <lang-float>` +- :ref:`double <lang-double>` +- :ref:`double() <lang-doublecast>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/for.rst b/docs/source/lang/cpp/for.rst new file mode 100644 index 0000000..71c5aca --- /dev/null +++ b/docs/source/lang/cpp/for.rst @@ -0,0 +1,142 @@ +.. highlight:: cpp + +.. _lang-for: + +``for`` +======= + +A ``for`` loop is used to repeat a block of statements enclosed in +curly braces. ``for`` loops are useful for performing repetitive +operations, and are often used in combination with :ref:`arrays +<lang-array>` to operate on collections of data or multiple +:ref:`pins <gpio>`. A ``for`` loop is composed of two parts: first, a +*header*, which sets up the for loop, and then a *body*, which is made +up of lines of code enclosed in curly braces. + +.. contents:: Contents + :local: + +Syntax +------ + +There are three parts to the ``for`` loop header: an *initialization* +expression, *loop condition* expression, and a *post-loop* +expression. The general syntax looks like this:: + + for (initialization; condition; post-loop) { + // all of these lines inside the curly braces are part + // of the loop body. + statement 1; + statement 2; + ... + } + +(Note that there is no semicolon after the post-loop). The +initialization happens first and exactly once, before the loop begins. +Each time through the loop, the condition is tested. The condition is +a :ref:`boolean <lang-boolean>` expression. If it is true, then the +list of statements inside the curly braces are executed. Next, the +post-loop is executed. The loop then begins again by evaluating the +condition again, entering the loop body if it is true. This proceeds +until the condition becomes false. + +Examples +-------- + +Here's an example:: + + // Dim an LED using a PWM pin + int pwmPin = 9; // LED in series with 470 ohm resistor on pin 9 + + void setup() { + pinMode(pwmPin, PWM); + } + + void loop() { + for (int i=0; i <= 65535; i++) { + pwmWrite(pwmPin, i); + delay(1); + } + } + +There is a ``for`` loop In the :ref:`loop() <lang-loop>` function of +the above example. This loop starts by declaring an ``int`` variable +named ``i``, whose value starts out at zero. The loop proceeds by +checking if ``i`` is less than or equal to 65535. Since ``i`` is +zero, this is true, and so the calls to :ref:`pwmWrite() +<lang-pwmwrite>` and :ref:`delay() <lang-delay>` happen next. At this +point, the post-loop expression ``i++`` is evaluated, which +:ref:`increments <lang-increment>` ``i``, so that ``i`` becomes one. +That concludes the first time through the loop. Each "time through +the loop" is referred to as an *iteration*. + +The loop then jumps back to the beginning, checking the condition as +the beginning of its second iteration (initialization is skipped, +since this only happens once, before the first iteration). One is +less than 65535, so the loop statements are executed again. This +proceeds over and over until the iteration when ``i`` finally +reaches 65536. At that point, the condition is no longer true, so the +loop stops executing, and the ``loop()`` function returns. + +Here's another example, using a ``for`` loop to brighten and fade an +LED (see the :ref:`pwmWrite() <lang-pwmwrite>` reference for more +information):: + + int pwmPin = 9; // hook up the LED to pin 9 + void loop() { + int x = 1; + for (int i = 0; i >= 0; i += x) { + analogWrite(pwmPin, i); // controls the brightness of the LED + if (i == 65535) { + x = -1; // switch direction, so i starts decreasing + } + delay(1); + } + } + +Coding Tips +----------- + +The C ``for`` loop is more flexible than ``for`` loops found in some +other computer languages, including BASIC. Any or all of the three +header elements may be left blank, although the semicolons are +required. Also the statements for initialization, condition, and +post-loop can be any valid C statements, and use any C datatypes, +including :ref:`floating point numbers <lang-double>`. These types +of unusual ``for`` loops sometimes provide solutions to less-common +programming problems. + +For example, using a multiplication in the post-loop line will +generate a `geometric progression +<http://en.wikipedia.org/wiki/Geometric_progression>`_:: + + for(int x = 1; x <= 100; x = x * 2) { + SerialUSB.println(x); + } + + +This loop prints out the numbers 1, 2, 4, 8, ..., 64. Check +your understanding of ``for`` loops by answering the following two +questions (answers are in footnote [#fanswers]_\ ): + +1. How many iterations occur before the loop finishes? + +2. Why does it stop at 64? + +See also +-------- + +- :ref:`while <lang-while>` loops +- :ref:`do <lang-dowhile>` loops + +.. rubric:: Footnotes + +.. [#fanswers] + 1. Seven. + + 2. After the seventh iteration, the post-loop causes ``x`` to + equal 128. This is larger than 100, so the loop condition is + false, and the loop stops. + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/goto.rst b/docs/source/lang/cpp/goto.rst new file mode 100644 index 0000000..ff2f248 --- /dev/null +++ b/docs/source/lang/cpp/goto.rst @@ -0,0 +1,130 @@ +.. highlight:: cpp + +.. _lang-goto: + +Labels and ``goto`` +=================== + +A *label* gives a name to a line of code within a function. You can +label a line by writing a name for it, then a colon (``:``), before +the line starts. The ``goto`` keyword allows program flow to transfer +to a labeled line from anywhere within the same function. + +.. warning:: The use of ``goto`` is discouraged in C and C++ + programming. It is *never necessary* to use ``goto`` to write a + program. + + Unless you know what you're doing, using ``goto`` tends to + encourage code which is harder to debug and understand than + programs without ``goto`` that do the same thing. That said, + however, it's sometimes useful; :ref:`see below <goto-when-to-use>` + for a concrete example. + +Using Labels and goto +--------------------- + +Labels and ``goto`` are probably best explained through example. +Let's start with an example of how to label lines. The first line +(``int x = analogRead(some_pin);``) in the :ref:`loop <lang-loop>` +function below has label ``readpin``. The third line (``delay(x);``) +has label ``startdelay``. The second line (``SerialUSB.println(x);``) +does not have a label:: + + void loop() { + readpin: + int x = analogRead(some_pin); + SerialUSB.println(x); // for debugging + startdelay: + delay(x); + // ... more code ... + } + +Anything which can be a :ref:`variable <lang-variables>` name can +be a label. + +Let's say that we wanted to print ``x`` only if it was very large, say +at least 2000. We might want to do this just so anybody watching on a +:ref:`serial monitor <ide-serial-monitor>` would know they were in for +a longer wait than usual. We can accomplish this through the use of a +``goto`` statement that skips the printing if ``x`` is less than +2000:: + + void loop() { + readpin: + int x = analogRead(some_pin); + if (x < 2000) { + goto startdelay; + } + SerialUSB.println(x); // for debugging + startdelay: + delay(x); + // ... more code ... + } + +In this modified program, whenever ``x`` is less than 2000, the body +of the :ref:`if <lang-if>` statement in the second line is +executed. The ``goto`` statement inside the ``if`` body skips +straight to the line labeled ``startdelay``, passing over the line +doing the printing. + +A ``goto`` does not have to "move forwards"; it can go "backwards", +too. For example, the following program prints "5" forever (why?):: + + void loop() { + printfive: + SerialUSB.println(5); + goto printfive; + SerialUSB.println(6); + } + +.. _goto-when-to-use: + +When to Use goto +---------------- + +As mentioned above, use of ``goto`` is `generally discouraged +<http://en.wikipedia.org/wiki/Goto#Criticism_and_decline>`_. However, +when used with care, ``goto`` can simplify certain programs. One +important use case for ``goto`` is breaking out of deeply nested +:ref:`for <lang-for>` loops or :ref:`if <lang-if>` logic blocks. +Here's an example:: + + for(int r = 0; r < 255; r++) { + for(int g = 255; g > -1; g--) { + for(int b = 0; b < 255; b++) { + if (analogRead(0) > 250) { + goto bailout; + } + // more statements ... + } + // innermost loop ends here + } + } + bailout: + // more code here + +In the above example, whenever the :ref:`analog reading +<lang-analogread>` on pin 0 was greater than 250, the program would +jump to the line labeled ``bailout``, exiting all three loops at once. + +While there is already a :ref:`break <lang-break>` keyword for +breaking out of a loop, it will only break out of the *innermost* +loop. So, if instead of saying "``goto bailout;``", there was a +"``break;``" instead, the program would only exit from the loop with +header "``for(int b = 0; b < 255; b++)``". The program would continue +at the line which reads "``// innermost loop ends here``", which is +clearly undesirable if you wanted to leave all three loops at once. + +More examples of when ``goto`` is a good choice are given in Donald +Knuth's paper, "Structured Programming with go to Statements"; see +below for a link. + +See Also +-------- + +- Dijkstra, Edsger W. `Go To Statement Considered Harmful <http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.92.4846&rep=rep1&type=pdf>`_ (PDF) + +- Knuth, Donald. `Structured Programming with go to Statements <http://pplab.snu.ac.kr/courses/adv_pl05/papers/p261-knuth.pdf>`_ (PDF) + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/if.rst b/docs/source/lang/cpp/if.rst new file mode 100644 index 0000000..bef89e2 --- /dev/null +++ b/docs/source/lang/cpp/if.rst @@ -0,0 +1,121 @@ +.. highlight:: cpp + +.. _lang-if: + +``if``/``else`` +=============== + +An ``if`` statement is used to execute code when certain conditions +are met. The general syntax for an ``if`` statement is:: + + if (condition) { + body + } + +An ``if`` statement first tests whether its *condition* is true (such +as an input being above a certain number). If the condition is true, +the ``if`` statement executes its *body*, which is made up of lines of +code inside :ref:`curly braces <lang-curly-braces>`. If the condition +is false, the body is not executed. Here's a more concrete example:: + + if (someVariable > 50) { + // do something here + } + +The program tests to see if ``someVariable`` is greater than 50. If it +is, the program executes every line in the curly braces (which in the +above example does nothing, since the body is just the :ref:`comment +<lang-comments>` line "``// do something here``"). + +Put another way, if the statement in parentheses is true, the +statements inside the braces are run. If not, the program skips over +the code. + +An ``if`` statement's condition (which is inside the parentheses after +``if``) often uses one or more :ref:`boolean <lang-boolean>` or +:ref:`comparison <lang-comparison>` operators. + +Writing the if Body +------------------- + +The brackets may be omitted after an ``if`` statement's +conditional. If this is done, the next line (which ends in a +semicolon) becomes the only line in the body. The following three +``if`` statements all do the same thing:: + + if (x > 120) digitalWrite(ledPin, HIGH); + + if (x > 120) + digitalWrite(ledPin, HIGH); + + if (x > 120) { + digitalWrite(ledPin, HIGH); + } + +However, the following two examples are different:: + + // example 1: two lines of code in the if body + if (x > 120) { + digitalWrite(ledPin1, HIGH); + digitalWrite(ledPin2, HIGH); + } + + // example 2: one line of code in the if body, and + // another line of code after the if statement + if (x > 120) + digitalWrite(ledPin1, HIGH); // this is in the if body + digitalWrite(ledPin2, HIGH); // this is NOT in the if body + +In the first example, since the body is enclosed in curly braces, both +lines are included. In the second example, since the curly braces are +missing, only the first line is in the ``if`` body. + +``else`` +-------- + +``if``/\ ``else`` allows greater control over the flow of code than +the basic :ref:`if <lang-if>` statement, by allowing multiple tests to +be grouped together. For example, an :ref:`analog input +<lang-analogread>` could be tested, with one action taken if the input +was less than 500, and another action taken if the input was 500 or +greater. The code would look like this:: + + if (pinFiveInput < 500) { + // action A + } else { + // action B + } + +``else`` can precede another ``if`` test, so that multiple, mutually +exclusive tests can be run at the same time. + +Each test will proceed to the next one until a true test is +encountered. When a true test is found, its associated block of code +is run, and the program then skips to the line following the entire +if/else construction. If no test proves to be true, the default +``else`` block is executed, if one is present, and sets the default +behavior. + +Note that an ``else if`` block may be used with or without a +terminating ``else`` block, and vice-versa. An unlimited number of +such ``else if`` branches is allowed. Here is a code example:: + + if (pinFiveInput < 500) { + // do Thing A + } else if (pinFiveInput >= 1000) { + // do Thing B + } else { + // do Thing C + } + +Another way to express branching, mutually exclusive tests, is with a +:ref:`switch/case <lang-switchcase>` statement. + + +See Also +-------- + +- :ref:`boolean operators <lang-boolean>` +- :ref:`comparison operators <lang-comparison>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/include.rst b/docs/source/lang/cpp/include.rst new file mode 100644 index 0000000..74fe7af --- /dev/null +++ b/docs/source/lang/cpp/include.rst @@ -0,0 +1,72 @@ +.. highlight:: cpp + +.. _lang-include: + +``#include`` +============ + +``#include`` is used to include outside libraries in your sketch. +This gives the programmer access to a large group of standard C +libraries (groups of pre-made functions and data types), and also +libraries written especially for Maple. + +Example +------- + +This example (from the `Arduino LiquidCrystal Tutorial +<http://arduino.cc/en/Tutorial/LiquidCrystal>`_) includes a library +that is used to control :ref:`LCD displays +<libraries-liquid-crystal>`:: + + // include the library code: + #include <LiquidCrystal.h> + + // initialize the library with the numbers of the interface pins + LiquidCrystal lcd(12, 11, 5, 4, 3, 2); + + void setup() { + // set up the LCD's number of columns and rows: + lcd.begin(16, 2); + // Print a message to the LCD. + lcd.print("hello, world!"); + } + + void loop() { + // set the cursor to column 0, line 1 + // (note: line 1 is the second row, since counting begins with 0): + lcd.setCursor(0, 1); + // print the number of seconds since reset: + lcd.print(millis()/1000); + } + +Note that a ``#include`` line, like :ref:`#define <lang-define>`, +has **no semicolon**. The compiler will print strange error messages +if you add one. + +C Standard Library +------------------ + +The standard C library that comes with Maple is called `newlib +<http://sourceware.org/newlib/>`_. Its main sources of documentation +are its `main reference <http://sourceware.org/newlib/libc.html>`_ +page and its `math functions +<http://sourceware.org/newlib/libm.html>`_ reference page. Here's an +example that imports the math.h library in order to take the `cube +root <http://en.wikipedia.org/wiki/Cube_root>`_ of a number:: + + #include <math.h> + + void setup() { + // no setup necessary + } + + void loop() { + // "cbrt" stands for "cube root" + double cubeRootOf3 = cbrt(3.0); + // prints a number that is approximately the cube root of 3: + SerialUSB.println(cubeRootOf3); + } + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/increment.rst b/docs/source/lang/cpp/increment.rst new file mode 100644 index 0000000..6dffa80 --- /dev/null +++ b/docs/source/lang/cpp/increment.rst @@ -0,0 +1,37 @@ +.. highlight:: cpp + +.. _lang-increment: + +Increment and Decrement Operators (``++``, ``--``) +================================================== + +These operators increment (add one to) or decrement (subtract one +from) a variable. If they come before the variable, they return its +new value; otherwise, they return its old value. + +Some quick examples:: + + x++; // adds one to x, and returns the old value of x + ++x; // adds one to x, and returns the new value of x + + x--; // decrement x by one and returns the old value of x + --x; // decrement x by one and returns the new value of x + +A more extended example:: + + x = 2; + y = ++x; // x now contains 3, y contains 3 + y = x--; // x contains 2 again, y still contains 3 + +.. warning:: Be careful! You cannot put a space in between the two + ``+`` or ``-`` signs. This example is broken:: + + // this line won't compile (notice the extra space): + int y = x+ +; + +See Also +-------- + +- :ref:`lang-compoundarithmetic` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/int.rst b/docs/source/lang/cpp/int.rst new file mode 100644 index 0000000..ca75f75 --- /dev/null +++ b/docs/source/lang/cpp/int.rst @@ -0,0 +1,64 @@ +.. highlight:: cpp + +.. _lang-int: + +``int`` +======= + +The ``int`` data type represents integers. Integers are your primary +data type for number storage, and store a 4 byte value. This yields a +range of -2,147,483,648 to 2,147,483,647 (minimum value of -2^31 and a +maximum value of (2^31) - 1; that's about negative 2 billion to +positive 2 billion). + +An ``int`` stores a negative number with a technique called `two's +complement math +<http://en.wikipedia.org/wiki/Two%27s_complement#Explanation>`_\ . +The highest bit in an ``int``, sometimes refered to as the "sign" bit, +flags the number as a negative number. (See the linked article on +two's complement for more information). + +The Maple takes care of dealing with negative numbers for you, so that +arithmetic operations work mostly as you'd expect. There can be an +:ref:`unexpected complication <lang-bitshift-signbit-gotcha>` in +dealing with the :ref:`bitshift right operator (>>) +<lang-bitshift>`, however. + +Here is an example of declaring an ``int`` variable named ``ledPin``, +then giving it value 13:: + + int ledPin = 13; + +The general syntax for declaring an ``int`` variable named ``var``, +then giving it value ``val``, looks like:: + + int var = val; + +.. _lang-int-overflow: + +Integer Overflow +---------------- + +When ``int`` variables leave the range specified above, they +:ref:`roll over <lang-variables-rollover>` in the other direction. +Here are some examples:: + + int x; + x = -2,147,483,648; + x--; // x now contains 2,147,483,647; rolled over "left to right" + + x = 2,147,483,647; + x++; // x now contains -2,147,483,648; rolled over "right to left" + +See Also +-------- + +- :ref:`unsigned int <lang-unsignedint>` +- :ref:`char <lang-char>` +- :ref:`unsigned char <lang-unsignedchar>` +- :ref:`long <lang-long>` +- :ref:`unsigned long <lang-unsignedlong>` +- :ref:`Integer Constants <lang-constants-integers>` +- :ref:`Variables <lang-variables>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/intcast.rst b/docs/source/lang/cpp/intcast.rst new file mode 100644 index 0000000..386fe14 --- /dev/null +++ b/docs/source/lang/cpp/intcast.rst @@ -0,0 +1,29 @@ +.. highlight:: cpp + +.. _lang-intcast: + +``int()`` (cast) +================ + +Converts a value to the :ref:`int <lang-int>` data type. Here is +an example:: + + double d = 2.5; + int i = int(d); // i holds "2", an int value + +The value inside of the parentheses (``int(...)``) can be of any type. +However, if it is not a numeric type (like ``double``, ``char``, +etc.), you will get strange results. + +See the :ref:`int <lang-int>` reference for details about the +precision and limitations of ``int`` variables on the Maple. + +See Also +-------- + +- :ref:`int <lang-int>` + + + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/keywords.rst b/docs/source/lang/cpp/keywords.rst new file mode 100644 index 0000000..e3bc20d --- /dev/null +++ b/docs/source/lang/cpp/keywords.rst @@ -0,0 +1,205 @@ +.. _lang-keywords: + +Keywords +======== + +This page lists all of the C++ keywords, and either links to a +reference page explaining their use, or provides a brief description. + +List of Keywords +---------------- + +The C++ keywords are: + +``and``, ``and_eq``, ``asm``, ``auto``, ``bitand``, ``bitor``, +``bool``, ``break``, ``case``, ``catch``, ``char``, ``class``, +``compl``, ``const``, ``const_cast``, ``continue``, ``default``, +``delete``, ``do``, ``double``, ``dynamic_cast``, ``else``, ``enum``, +``explicit``, ``export``, ``extern``, ``false``, ``float``, ``for``, +``friend``, ``goto``, ``if``, ``inline``, ``int``, ``long``, +``mutable``, ``namespace``, ``new``, ``not``, ``not_eq``, +``operator``, ``or``, ``or_eq``, ``private``, ``protected``, +``public``, ``register``, ``reinterpret_cast``, ``return``, ``short``, +``signed``, ``sizeof``, ``static``, ``static_cast``, ``struct``, +``switch``, ``template``, ``this``, ``throw``, ``true``, ``try``, +``typedef``, ``typeid``, ``typename``, ``union``, ``unsigned``, +``using``, ``virtual``, ``void``, ``volatile``, ``wchar_t``, +``while``, ``xor``, ``xor_eq`` + +Boolean Operator Synonyms +------------------------- + +- ``and`` is a synonym for :ref:`&& <lang-boolean-and>`. +- ``not`` is a synonym for :ref:`\! <lang-boolean-not>`. +- ``not_eq`` is a synonym for :ref:`\!= <lang-comparison>`. +- ``or`` is a synonym for :ref:`|| <lang-boolean-or>`. + +Bitwise Operator Synonyms +------------------------- + +- ``and_eq`` is a synonym for :ref:`&= <lang-compoundbitwise-and>`. +- ``bitand`` is a synonym for (bitwise) :ref:`& <lang-bitwisemath-and>`. +- ``bitor`` is a synonym for :ref:`\| <lang-bitwisemath-or>`. +- ``compl`` is a synonym for :ref:`~ <lang-bitwisemath-not>`. +- ``or_eq`` is a synonym for :ref:`|= <lang-compoundbitwise-or>`. +- ``xor`` is a synonym for :ref:`^ <lang-bitwisemath-xor>`. +- ``xor_eq`` is a synonym for :ref:`^= <lang-compoundbitwise-xor>`. + +Constants +--------- + +- ``true`` and ``false`` are the :ref:`boolean constants + <lang-booleanvariables>`. + +Control Flow +------------ + +- ``break`` can exit out of a :ref:`switch statement + <lang-switchcase>` or a :ref:`for <lang-for>`, :ref:`do + <lang-dowhile>`, or :ref:`while <lang-while>` loop. + +- ``case`` defines alternatives in a :ref:`switch statement <lang-switchcase>`. + +- ``continue`` will move control flow to the next iteration of the + enclosing :ref:`for <lang-for>`, :ref:`do <lang-dowhile>`, or + :ref:`while <lang-while>` loop. + +- ``default`` defines the default alternative in a :ref:`switch + statement <lang-switchcase>`. + +- ``do`` introduces a :ref:`do <lang-dowhile>` loop. + +- ``else`` is used in :ref:`if statements <lang-if>`. + +- ``for`` introduces a :ref:`for <lang-for>` loop. + +- ``goto`` :ref:`jumps <lang-goto>` to a label. + +- ``if`` introduces an :ref:`if statement <lang-if>`. + +- ``return`` :ref:`transfers flow to a function's caller <lang-return>`. + +- ``switch`` introduces a :ref:`switch statement <lang-switchcase>`. + +- ``while`` introduces a :ref:`while <lang-while>` loop. + +Types +----- + +The following keywords are used for built-in types. + +- :ref:`bool <lang-booleanvariables>` +- :ref:`lang-char` +- :ref:`lang-double` +- :ref:`lang-float` +- :ref:`lang-int` +- :ref:`lang-long` +- :ref:`short <lang-built-in-types-integral>` +- :ref:`void <lang-void>` (not really a type, but used in the absence + of one) + +The following keywords are used to introduce new types. + +- :ref:`enum <lang-enum>` + +Qualifiers +---------- + +- :ref:`static <lang-static>` can be used to declare persistent local + variables; it has other uses not documented here. + +- ``unsigned`` is used to specify an unsigned integral type. + Examples: :ref:`lang-unsignedint`, :ref:`lang-unsignedchar`, + :ref:`lang-unsignedlong`. + +- :ref:`volatile <lang-volatile>` is useful when declaring variables + that may be modified by external interrupts. + +- :ref:`const <lang-const>` is used to define constants. + +Other +----- + +These keywords are not described in the Maple documentation. For more +information, consult a C++ reference. + +- ``asm`` is used to insert literal assembly language. + +- ``auto`` is used to declare that a variable has automatic storage. + +- ``catch`` is used in exception handling. Note that the default + flags we pass to :ref:`GCC <arm-gcc>` include ``-fno-exceptions``. + +- ``class`` is used to define classes. + +- ``const_cast`` is used in typecasting. + +- ``delete`` is used to free ``new``\ -allocated storage. Note that + dynamic memory allocation is not available by default on the Maple, + so you'll have to bring your own ``new`` and ``delete`` if you want + this. + +- ``dynamic_cast`` is used in typecasting. + +- ``explicit`` is used to declare constructors that can be called only + explicitly. + +- ``export`` declares a template definition accessible to other + compilation units. + +- ``extern`` can mark a declaration as a declaration and not a + definition, and also grant external linkage to a ``const`` or + ``typedef``. + +- ``friend`` is used to declare that certain functions have access to + a class's private variables. + +- ``inline`` is a compiler hint to inline a function. + +- ``mutable`` specifies that a member can be updated, even when a + member of a ``const`` object. + +- ``namespace`` declares a new namespace. + +- ``new`` dynamically allocates space for a value. Note that dynamic + memory allocation is not available by default on the Maple, so + you'll have to bring your own ``new`` and ``delete`` if you want + this. + +- ``operator`` is used to define type-specific operator overrides. + +- ``private`` declares a private class member. + +- ``protected`` declares a protected class member. + +- ``public`` declares a public class member. + +- ``register`` is a compiler hint to store a variable in a register. + +- ``reinterpret_cast`` is used in typecasting. + +- ``signed`` is the opposite of ``unsigned``. + +- ``static_cast`` is used in typecasting. + +- ``struct`` declares a new struct. + +- ``template`` introduces a template class, function, etc. + +- ``this`` is a pointer to the receiver object. + +- ``throw`` is used in exception handling. Note that the default + flags we pass to :ref:`GCC <arm-gcc>` include ``-fno-exceptions``. + +- ``try`` is used in exception handling. Note that the default + flags we pass to :ref:`GCC <arm-gcc>` include ``-fno-exceptions``. + +- ``typedef`` defines a type synonym. + +- ``union`` defines an untagged union. + +- ``using`` is a directive related to namespaces. + +- ``virtual`` declares a method which may be overridden. + +- ``wchar_t`` is the wide character type. diff --git a/docs/source/lang/cpp/long.rst b/docs/source/lang/cpp/long.rst new file mode 100644 index 0000000..d8498c0 --- /dev/null +++ b/docs/source/lang/cpp/long.rst @@ -0,0 +1,52 @@ +.. highlight:: cpp + +.. _lang-long: + +``long`` +======== + +The ``long`` data type stores extended size integer values. You can +use a ``long`` when your values are too large to fit into an :ref:`int +<lang-int>`. A ``long`` occupies 8 bytes of memory. This yields a +range of approximately -9.2×10^18 to 9.2×10^18 (that's 9.2 billion +billion, or about 92 million times the number of stars in the Milky +Way galaxy). The exact range of a ``long`` on the Maple is from +-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807, or -2^63 to +(2^63-1). A ``long`` it is subject to the same :ref:`overflow issues +<lang-variables-rollover>` as any numeric data type. + +Here's an example of declaring a long (see :ref:`integer constants +<lang-constants-integers-u-l>` for an explanation of the "L" at the end of the +number):: + + // Speed of light in nanometers per second (approximate). + long c = 299792458000000000L; + +The general syntax for declaring an ``long`` variable named ``var``, +then giving it value ``val``, looks like:: + + long var = val; + +This is identical to the ``int`` syntax, with ``long`` replacing +``int``. + +Note that ``long`` values will still :ref:`overflow +<lang-int-overflow>`, just like ``int`` values, but their much +larger range makes this less likely to happen. + +The downside to using a ``long`` instead of an ``int`` (besides the +extra storage) is that :ref:`arithmetic <lang-arithmetic>` operations +on ``long``\ s will take slightly longer than on ``int``\ s. + +See Also +-------- + +- :ref:`char <lang-char>` +- :ref:`unsigned char <lang-unsignedchar>` +- :ref:`int <lang-int>` +- :ref:`unsigned int <lang-unsignedint>` +- :ref:`unsigned long <lang-unsignedlong>` +- :ref:`Integer Constants <lang-constants-integers>` +- :ref:`Variables <lang-variables>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/longcast.rst b/docs/source/lang/cpp/longcast.rst new file mode 100644 index 0000000..2b92345 --- /dev/null +++ b/docs/source/lang/cpp/longcast.rst @@ -0,0 +1,27 @@ +.. highlight:: cpp + +.. _lang-longcast: + +``long()`` (cast) +================= + +Converts a value to the :ref:`long <lang-long>` data type. Here is +an example:: + + double d = 2.5; + long i = long(d); // i holds "2L", an long value + +The value inside of the parentheses (``long(...)``) can be of any type. +However, if it is not a numeric type (like ``double``, ``char``, +etc.), you will get strange results. + +See the :ref:`long <lang-long>` reference for details about the +precision and limitations of ``long`` variables on the Maple. + +See Also +-------- + +- :ref:`long <lang-long>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/modulo.rst b/docs/source/lang/cpp/modulo.rst new file mode 100644 index 0000000..289fba0 --- /dev/null +++ b/docs/source/lang/cpp/modulo.rst @@ -0,0 +1,70 @@ +.. highlight:: cpp + +.. _lang-modulo: + +Modulo Operator (``%``) +======================= + +Calculates the `remainder <http://en.wikipedia.org/wiki/Remainder>`_ +when one integer is divided by another. It is useful for keeping a +variable within a particular range (e.g. the size of an array). + +Syntax +------ + +:: + + dividend % divisor + +Parameters +---------- + +**dividend**: the number to be divided + +**divisor**: the number to divide by + +Returns +------- + +The remainder of **dividend**\ /\ **divisor**\ . + +Examples +-------- + +:: + + int x; + x = 7 % 5; // x now contains 2 + x = 9 % 5; // x now contains 4 + x = 5 % 5; // x now contains 0 + x = 4 % 5; // x now contains 4 + +:: + + /* update one value in an array each time through a loop */ + + int values[10]; + int i = 0; + + void setup() { + // no setup necessary + } + + void loop() { + values[i] = analogRead(0); + i = (i + 1) % 10; // modulo operator makes sure i stays between 0 and 9 + } + +Tip +--- + +The modulo operator does not work on floats. For that, you can use +the C standard library function `fmod() +<http://sourceware.org/newlib/libm.html#fmod>`_. + +See Also +-------- + +- :ref:`Arithmetic <lang-arithmetic>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/pointer.rst b/docs/source/lang/cpp/pointer.rst new file mode 100644 index 0000000..0a42270 --- /dev/null +++ b/docs/source/lang/cpp/pointer.rst @@ -0,0 +1,31 @@ +.. _lang-pointer: + +Pointer Operators (``&``, ``*``) +================================ + +The pointer operators ``&`` (reference) and ``*`` (dereference) are +different from the bitwise math operator :ref:`& +<lang-bitwisemath-and>` and the arithmetic operator :ref:`* +<lang-arithmetic>`. + +Pointers are one of the more complicated subjects for beginners in +learning C, and it is possible to write many useful Arduino sketches +without ever encountering pointers. However, for manipulating certain +data structures, the use of pointers can simplify the code, improve +its efficiency, and generally provide many benefits that would be +difficult to achieve without the use of pointers. + +Introducing pointers is somewhat outside the scope of this +documentation. However, a good `pointer tutorial +<http://www.cplusplus.com/doc/tutorial/pointers/>`_ is available. +Also see the `Wikipedia article on pointers +<http://en.wikipedia.org/wiki/Pointer_%28computing%29>`_, especially +the section on `pointers in C +<http://en.wikipedia.org/wiki/Pointer_%28computing%29#C_pointers>`_. + +See Also +-------- + +- http://xkcd.com/138/ + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/return.rst b/docs/source/lang/cpp/return.rst new file mode 100644 index 0000000..7b5039e --- /dev/null +++ b/docs/source/lang/cpp/return.rst @@ -0,0 +1,61 @@ +.. highlight:: cpp + +.. _lang-return: + +``return`` +========== + +Terminates a function and return a value from a function to the +calling function, if the function has non-``void`` return type. + +Syntax: +------- + +:: + + // from within a "void" function: + return; + + // from within a non-"void" function: + return value; + +In the second case, ``value`` should have a type which is the same as +the return type of the function, or be convertible to it (like an +``int`` to a ``long``, etc.; see :ref:`this note +<lang-arithmetic-typeconversion>` for some references). + +Examples: +--------- + +A function to compare a sensor input to a threshold:: + + // converts analog readings between 0 and 400 to 0, and 400 up to 1. + int checkSensor() { + if (analogRead(0) > 400) { + return 1; + else { + return 0; + } + } + +An early ``return`` is also useful when testing a section of code +without having to "comment out" large sections of possibly buggy code, +like so:: + + void loop() { + + // brilliant code idea to test here + + return; + + // the rest of a dysfunctional sketch here + // this code will never be executed + } + +See Also +-------- + +- :ref:`comments <lang-comments>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/scope.rst b/docs/source/lang/cpp/scope.rst new file mode 100644 index 0000000..7b65bab --- /dev/null +++ b/docs/source/lang/cpp/scope.rst @@ -0,0 +1,120 @@ +.. highlight:: cpp + +.. _lang-scope: + +Scope +===== + +Variables in the C++ programming language, which Maple uses (all of +your sketches are C++ programs in disguise), have a property called +*scope*. Simply put, a variable's scope is made up of all of the +lines where the variable can be used. + +Scope in C++ is a fairly complex topic, so we won't try to describe it +in full here. Instead, we present a simplified view, describing two +different kinds of scopes, *global* and *local*. For more detailed +information, consult a C++ reference. + +Global and Local Variables +-------------------------- + +A global variable is one that can be "seen" by every function in a +program. In the :ref:`Maple IDE <ide>`, any variable declared outside +of a function (like :ref:`setup() <lang-setup>` and :ref:`loop() +<lang-loop>`) is a global variable. + +A local variable can only be "seen" inside of a particular function. +You can declare a variable to be local to a function by declaring it +inside of the :ref:`curly braces <lang-curly-braces>` which enclose +that function. + +When programs start to get larger and more complex, local variables +are a useful way to ensure that a function has exclusive access to its +own variables. This prevents programming errors when one function +mistakenly modifies variables used by another function. + +It is also sometimes useful to declare and initialize a variable +inside a :ref:`for <lang-for>` loop. This creates a variable that +can only be accessed from inside the loop body. + +Example +------- + +Here is an example sketch (which you can copy into the Maple IDE and +run on your Maple) that illustrates the use of global and local +variables, as well as declaring variables inside of a ``for`` loop. +Be sure to open a :ref:`serial monitor <ide-serial-monitor>` after you +:ref:`verify <ide-verify>` and :ref:`upload <ide-upload>` the sketch:: + + int globalVar; // any function will see this variable + + void setup() { + // since "globalVar" is declared outside of any function, + // every function can "see" and use it: + globalVar = 50; + + // the variables "i" and "d" declared inside the "loop" function + // can't be seen here. see what happens when you uncomment the + // following lines, and try to Verify (compile) the sketch: + // + // i = 16; + // SerialUSB.print("i = "); + // SerialUSB.println(i); + // d = 26.5; + // SerialUSB.print("d = "); + // SerialUSB.println(d); + } + + void loop() { + // since "i" and "d" are declared inside of the "loop" function, + // they can only be seen and used from inside of it: + int i; + double d; + + for (int j = 0; j < 5; j++) { + // variable i can be used anywhere inside the "loop" function; + // variable j can only be accessed inside the for-loop brackets: + i = j * j; + SerialUSB.print("i = "); + SerialUSB.println(i); + } + + // globalVar can be accessed from anywhere. note how even + // though we set globalVar = 50 in the "setup" function, we can + // see that value here: + SerialUSB.print("globalVar = "); + SerialUSB.println(globalVar); + + // d can be accessed from anywhere inside the "loop" function: + d = 26.5; + SerialUSB.print("d = "); + SerialUSB.print(d); + SerialUSB.println(" (before separateFunction())"); + + separateFunction(); + + // notice how even though separateFunction() has a variable + // named "d", it didn't touch our (local) variable which has + // the same name: + SerialUSB.print("d = "); + SerialUSB.print(d); + SerialUSB.println(" (after separateFunction())"); + } + + void separateFunction() { + // variable "d" here has the same name as variable "d" inside of + // the "loop" function, but since they're both _local_ + // variables, they don't affect each other: + double d = 30.5; + SerialUSB.print("d = "); + SerialUSB.print(d); + SerialUSB.println(" (inside of separateFunction())"); + } + +See Also +-------- + +- `C++ programming Wikibook <http://en.wikibooks.org/wiki/C%2B%2B_Programming/Programming_Languages/C%2B%2B/Code/Statements/Scope>`_. +- Wikipedia article on `scope <http://en.wikipedia.org/wiki/Scope_%28programming%29>`_ + +.. include:: cc-attribution.txt diff --git a/docs/source/arduino/semicolon.rst b/docs/source/lang/cpp/semicolon.rst index b3cc8c4..8164616 100644 --- a/docs/source/arduino/semicolon.rst +++ b/docs/source/lang/cpp/semicolon.rst @@ -1,16 +1,11 @@ -.. _arduino-semicolon: +.. highlight:: cpp -; semicolon -=========== +.. _lang-semicolon: -Used to end a statement. +Semicolon (``;``) +================= - - -Example -~~~~~~~ - -:: +Used to end a line of code. Example:: int a = 13; @@ -25,3 +20,6 @@ missing semicolon, in the immediate vicinity, preceding the line at which the compiler complained. + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/sizeof.rst b/docs/source/lang/cpp/sizeof.rst new file mode 100644 index 0000000..eae509c --- /dev/null +++ b/docs/source/lang/cpp/sizeof.rst @@ -0,0 +1,64 @@ +.. highlight:: cpp + +.. _lang-sizeof: + +``sizeof()`` +============ + +The ``sizeof`` operator on the Maple returns the number of bytes +needed to store a value of a given type\ [#fcharsize]_. This can be +an ordinary numeric type, like ``int``. It can be something more +complicated, like a ``struct`` or ``union``. If the argument to +``sizeof`` is an array, it returns the total number of bytes occupied +by the array. + +The general syntax looks like this:: + + sizeof(type) + sizeof(var) + +Example +------- + +The ``sizeof`` operator is useful for dealing with arrays (such as +strings) where it is convenient to be able to change the size of the +array without breaking other parts of the program. + +This program prints out a text string one character at a time. Try +changing the text phrase:: + + char myStr[] = "this is a test"; + int i; + + void setup() { + Serial.begin(9600); + } + + void loop() { + for (i = 0; i < sizeof(myStr) - 1; i++) { + Serial.print(i, DEC); + Serial.print(" = "); + Serial.println(myStr[i], BYTE); + } + } + + +Note that ``sizeof`` returns the total number of bytes. So for larger +variable types such as ``int``, the :ref:`for loop <lang-for>` +would look something like this:: + + for (i = 0; i < (sizeof(myInts)/sizeof(int)) - 1; i++) { + // do something with myInts[i] + } + +.. rubric:: Footnotes + +.. [#fcharsize] Technically (and pedantically) speaking, ``sizeof`` + returns a multiple of the number of bits a ``char`` occupies in + memory. However, on the Maple (this goes for most C++ + implementations), a ``char`` occupies 8 bits = 1 byte. All the C++ + standard guarantees, however, is that a ``char`` occupies at + *least* 8 bits. + +.. include:: cc-attribution.txt + diff --git a/docs/source/lang/cpp/sqrt.rst b/docs/source/lang/cpp/sqrt.rst new file mode 100644 index 0000000..956a754 --- /dev/null +++ b/docs/source/lang/cpp/sqrt.rst @@ -0,0 +1,25 @@ +.. _lang-sqrt: + +sqrt() +====== + +Calculates the square root of a number. + +Library Documentation +--------------------- + +.. doxygenfunction:: sqrt + +Arduino Compatibility +--------------------- + +The Maple versino of ``sqrt()`` is compatible with Arduino. + +See Also +-------- + +- :ref:`pow <lang-pow>` +- :ref:`sq <lang-sq>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/static.rst b/docs/source/lang/cpp/static.rst new file mode 100644 index 0000000..5d1802e --- /dev/null +++ b/docs/source/lang/cpp/static.rst @@ -0,0 +1,57 @@ +.. highlight:: cpp + +.. _lang-static: + +``static`` +========== + +The ``static`` keyword can be used to create variables that are +visible to only one function. However, unlike local variables that get +created and destroyed every time a function is called, ``static`` +variables persist beyond the function call, preserving their data +between function calls. + +Variables declared as ``static`` will only be created and initialized +the first time a function is called. + +.. note:: This is only one use of the ``static`` keyword in C++. It + has some other important uses that are not documented here; consult + a reliable C++ reference for details. + +Example +------- + +One use case for ``static`` variables is implementing counters that +last longer than the functions which need them, but shouldn't be +shared to other functions. Here's an example:: + + void setup() { + SerialUSB.begin(); + } + + void loop() { + int reading; + if (timeToReadSensors()) { + reading = readSensors(); + } + // do something with reading + } + + int readSensors() { + static int numSensorReadings = 0; + numSensorReadings++; + if (numSensorReadings % 100 == 0) { + SerialUSB.print("just got to another 100 sensor readings"); + } + return analogRead(...); + } + +In this example, the static variable ``numSensorReadings`` is +initialized to zero the first time ``readSensors()`` is called, and +then incremented, so it starts out at one. Subsequent calls to +``readSensors()`` won't reset ``numSensorReadings`` to zero, because +it was declared ``static``. Thus, ``numSensorReadings`` is a count of +the number of times that ``readSensors()`` has been called. + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/string.rst b/docs/source/lang/cpp/string.rst new file mode 100644 index 0000000..0a270da --- /dev/null +++ b/docs/source/lang/cpp/string.rst @@ -0,0 +1,128 @@ +.. highlight:: cpp + +.. _lang-string: + +Strings +======= + +Text strings can be represented in two ways. You can + +1. Use the :ref:`String <lang-stringclass>` data type, which is +part of the core as of version 0.0.9, or + +2. You can make a string out of an array of type :ref:`char +<lang-char>` and null-terminate it. + +This page describes the second method. + +Examples +-------- + +All of the following are valid declarations for strings:: + + char str1[15]; + char str2[6] = {'m', 'a', 'p', 'l', 'e'}; + char str3[6] = {'m', 'a', 'p', 'l', 'e', '\0'}; + char str4[ ] = "maple"; + char str5[6] = "maple"; + char str6[15] = "maple"; + +As you can see, there are several methods available for declaring and +initializing strings: + +- Declare an array of ``char`` without initializing it, as with ``str1``. + +- Declare an array of ``char`` (with one extra ``char``) and the + compiler will add the required null character, as with ``str2``. + +- Explicitly add the null character (``'\0'``), as with ``str3``. + +- Initialize with a string constant in quotation marks (``"..."``); + the compiler will size the array to fit the string constant and a + terminating null character (``str4``). + +- Initialize the array with an explicit size and string constant, + (``str5``). + +- Initialize the array, leaving extra space for a larger string + (``str6``). + +Null Termination +---------------- + +Generally, strings are terminated with a null character (`ASCII +<http://en.wikipedia.org/wiki/ASCII>`_ code 0). This allows functions +(like ``SerialUSB.print()``) to tell where the end of a string is. +Otherwise, they would continue reading subsequent bytes of memory that +aren't actually part of the string. + +This means that your string needs to have space for one more character +than the text you want it to contain. That is why ``str2`` and +``str5`` need to be six characters, even though "maple" is only five +-- the last position is automatically filled with a NULL +character. ``str4`` will be automatically sized to six characters, one +for the extra null. In the case of ``str3``, we've explicitly included +the null character (written ``'\0'``) ourselves. + +Note that it's possible to have a string without a final null +character (e.g. if you had specified the length of ``str2`` as five +instead of six). This will break most functions that use strings, so +you shouldn't do it intentionally. If you notice something behaving +strangely (operating on characters not in the string), however, this +could be the problem. + +Single quotes or double quotes? +------------------------------- + +Strings are always defined inside double quotes (``"Abc"``) and +characters are always defined inside single quotes (``'A'``). + +Wrapping long strings +--------------------- + +You can wrap long strings like this:: + + char myString[] = "This is the first line" + " this is the second line" + " etcetera"; + +Arrays of Strings +----------------- + +It is often convenient, when working with large amounts of text, +such as a project with an LCD display, to setup an array of +strings. Because strings themselves are arrays, this is in actually +an example of a two-dimensional array. + +In the code below, the asterisk after the datatype char ``char *`` +indicates that this is an array of "pointers". All array names are +actually pointers, so this is required to make an array of arrays. +Pointers are one of the more esoteric parts of C for beginners to +understand, but it isn't necessary to understand pointers in detail to +use them effectively here:: + + char* myStrings[] = {"This is string 1", "This is string 2", + "This is string 3", "This is string 4", + "This is string 5", "This is string 6"}; + + void setup() { + SerialUSB.begin(); + } + + void loop() { + for (int i = 0; i < 6; i++) { + SerialUSB.println(myStrings[i]); + delay(500); + } + } + + +See Also +-------- + +- :ref:`array <lang-array>` +- :ref:`__attribute__ <arm-gcc-attribute-flash>` +- :ref:`Variables <lang-variables>` + + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/switchcase.rst b/docs/source/lang/cpp/switchcase.rst new file mode 100644 index 0000000..b484bc5 --- /dev/null +++ b/docs/source/lang/cpp/switchcase.rst @@ -0,0 +1,118 @@ +.. highlight:: cpp + +.. _lang-switchcase: + +``switch``\ /\ ``case`` +======================= + +Like :ref:`if <lang-if>` statements, A ``switch`` statement controls +program flow by allowing you to specify different code that should be +executed under various cases. + +The general syntax looks like this:: + + switch (var) { + case val1: + // statements + break; + case val2: + // statements + break; + ... + default: + // statements + } + +Where ``var`` is a variable whose value to investigate, and the +``val1``, ``val2`` after each ``case`` are constant values that +``var`` might be. + +Description +----------- + +A ``switch`` statement compares the value of a variable to the values +specified in ``case`` statements. When a ``case`` statement is found +whose value matches that of the variable, the code in that case +statement is run. + +Here's a more concrete example:: + + switch (var) { + case 1: + doThing1(); + break; + case 2: + doThing2(); + break; + } + afterTheSwitch(); + +In the above example, if ``var == 1``, then the code beginning on the +line after ``case 1`` gets executed. That is, if ``var`` is one, +``doThing1()`` gets called first, and then the ``break`` statement is +executed. + +The ``break`` keyword exits the ``switch`` statement, and is typically +used at the end of each ``case``. Since there is a ``break`` at the +end of ``case 1``, the ``switch`` statement exits, and the next line +to be run is the one which calls ``afterTheSwitch()``. + +Without a ``break``, the ``switch`` statement will continue executing +the following ``case`` expressions ("falling-through") until a +``break`` (or the end of the switch statement) is reached. Let's +pretend the ``switch`` looked like this instead:: + + switch (var) { + case 1: + doThing1(); + // no break statement anymore + case 2: + doThing2(); + break; + } + afterTheSwitch(); + +Now, if ``var`` is one, ``doThing1()`` gets executed like before. +However, without a ``break``, the code would continue to be executed +line-by-line, so ``doThing2()`` would be called next. At this point, +a ``break`` has been reached, so the program continues by calling +``afterTheSwitch()``. This is usually not what you want, which is why +each ``case`` usually has a ``break`` at the end. + +.. _lang-switchcase-default: + +Writing "``default:``" instead of a ``case`` statement allows you to +specify what to do if none of the ``case`` statements matches. Having +a ``default`` is optional (you can leave it out), but if you have one, +it must appear after all of the ``case`` statements. Let's add a +``default`` to the ``switch`` we've been discussing:: + + switch (var) { + case 1: + doThing1(); + break; + case 2: + doThing2(); + break; + default: + doSomethingElse(); + } + afterTheSwitch(); + +If ``var`` is one, then ``doThing1()`` gets called. If ``var`` is +two, ``doThing2()`` gets called. If ``var`` is anything else, +``doSomethingElse()`` gets called. As stated above, a ``default`` is +optional. If you're missing one and none of the ``case`` statements +match, the ``switch`` does nothing at all, as if it weren't there. + +``switch`` statements are often used with an :ref:`enum <lang-enum>` +value as the variable to compare. In this case, you can write down +all of the values the ``enum`` takes as ``case`` statements, and be +sure you've covered all the possibilities. + +See also: +--------- + +- :ref:`if/else <lang-if>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/unsignedchar.rst b/docs/source/lang/cpp/unsignedchar.rst new file mode 100644 index 0000000..5b946ed --- /dev/null +++ b/docs/source/lang/cpp/unsignedchar.rst @@ -0,0 +1,33 @@ +.. highlight:: cpp + +.. _lang-unsignedchar: + +``unsigned char`` +================= + +An unsigned version of the :ref:`char <lang-char>` data type. An +``unsigned char`` occupies 1 byte of memory; it stores an integer from +0 to 255. + +Like an :ref:`unsigned int <lang-unsignedint>`, an ``unsigned char`` +won't store negative numbers; it is also subject to the same +:ref:`overflow issues <lang-int-overflow>` as any integral data type. + +Example +------- + +:: + + unsigned char c = 240; + +See Also +-------- + + +- :ref:`byte <lang-byte>` +- :ref:`int <lang-int>` +- :ref:`array <lang-array>` +- :ref:`SerialUSB.println() <lang-serialusb-println>` +- :ref:`Serial.println() <lang-serial-println>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/unsignedint.rst b/docs/source/lang/cpp/unsignedint.rst new file mode 100644 index 0000000..f6311da --- /dev/null +++ b/docs/source/lang/cpp/unsignedint.rst @@ -0,0 +1,55 @@ +.. highlight:: cpp + +.. _lang-unsignedint: + +``unsigned int`` +================ + +An ``unsigned int`` (unsigned integer) is the same as an :ref:`int +<lang-int>` in that it stores a 4 byte integer value. However, +Instead of storing both negative and positive numbers, an ``unsigned +int`` can only store nonnegative values, yielding a range of 0 to +4,294,967,295 (the positive value is 2^32 - 1). + +The difference between an ``unsigned int`` and a (signed) ``int`` lies +in the way the highest bit, sometimes referred to as the "sign" bit, +is interpreted. In the case of the Maple ``int`` type (which is +signed), if the high bit is a "1", the number is interpreted as a +negative number, using a technique known as `two's complement math +<http://en.wikipedia.org/wiki/Two%27s_complement#Explanation>`_. The +bits in an an ``unsigned int`` are interpreted according to the usual +rules for converting `binary to decimal +<http://en.wikipedia.org/wiki/Binary_numeral_system#Counting_in_binary>`_. + +An ``unsigned int`` is subject to the same :ref:`overflow issues +<lang-int-overflow>` as a regular ``int``; the only difference is +that an ``unsigned int`` will "underflow" at 0, and "overflow" at +4,294,967,295. Here is some example code which illustrates this:: + + unsigned int x; + x = 0; + x--; // x now contains 4,294,967,295; rolled over "left to right" + x++; // x now contains 0; rolled over "right to left" + +Here is an example of declaring an ``unsigned int`` variable named +``ledPin``, then giving it value 13:: + + unsigned int ledPin = 13; + +The general syntax for declaring an ``unsigned int`` variable named +``var``, then giving it value ``val``, looks like:: + + unsigned int var = val; + +See Also +-------- + +- :ref:`int <lang-int>` +- :ref:`char <lang-char>` +- :ref:`unsigned char <lang-unsignedchar>` +- :ref:`long <lang-long>` +- :ref:`unsigned long <lang-unsignedlong>` +- :ref:`Integer Constants <lang-constants-integers>` +- :ref:`Variables <lang-variables>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/unsignedlong.rst b/docs/source/lang/cpp/unsignedlong.rst new file mode 100644 index 0000000..14a4fc3 --- /dev/null +++ b/docs/source/lang/cpp/unsignedlong.rst @@ -0,0 +1,41 @@ +.. highlight:: cpp + +.. _lang-unsignedlong: + +``unsigned long`` +================= + +An unsigned version of the :ref:`long <lang-long>` data type. An +``unsigned long`` occupies 8 bytes of memory; it stores an integer +from 0 to 2^64-1, which is approximately 1.8×10^19 (18 quintillion, or +18 billion billion). + +Like an :ref:`unsigned int <lang-unsignedint>`, an ``unsigned long`` +won't store negative numbers; it is also subject to the same +:ref:`overflow issues <lang-int-overflow>` as any integral data type. + +Here is an example of declaring an ``unsigned long`` variable named +``c``, then giving it value 299,792,458,000,000,000 (see :ref:`integer +constants <lang-constants-integers-u-l>` for an explanation of the "L" +at the end of the number):: + + // Speed of light in nanometers per second (approximate). + unsigned long c = 299792458000000000L; + +The general syntax for declaring an ``unsigned long`` variable named +``var``, then giving it value ``val``, looks like:: + + unsigned long var = val; + +See Also +-------- + +- :ref:`long <lang-long>` +- :ref:`int <lang-int>` +- :ref:`unsigned <lang-unsignedint>` +- :ref:`char <lang-char>` +- :ref:`unsigned char <lang-unsignedchar>` +- :ref:`Integer Constants <lang-constants-integers>` +- :ref:`Variables <lang-variables>` + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/variables.rst b/docs/source/lang/cpp/variables.rst new file mode 100644 index 0000000..e6da0c9 --- /dev/null +++ b/docs/source/lang/cpp/variables.rst @@ -0,0 +1,170 @@ +.. highlight:: cpp + +.. _lang-variables: + +Variables +========= + +A variable is a way of naming and storing a value for later use by +the program, such as data from a sensor or an intermediate value +used in a calculation. + +.. contents:: Contents + :local: + +.. _lang-variables-declaring: + +Declaring Variables +------------------- + +Before they are used, all variables have to be *declared*. Declaring a +variable means defining its type, giving it a name, and (optionally) +giving it an initial value (this is often referred to as +*initializing* the variable). Variables do not have to be initialized +(given a value) when they are declared, but it is good style to give +them an initial value whenever possible. + +Here is an example of declaring a variable named ``inputVariable1`` +with type :ref:`int <lang-int>` (the ``int`` type is used to store +integers, like -2, -1, 0, 1, etc.):: + + int inputVariable1; + +In the above declaration, we did not give the variable an initial +value. Here is another example, where we declare an ``int`` variable +named ``inputVariable2``, with an initial value of ``0``:: + + int inputVariable2 = 0; + +The Maple environment comes ready to use with many useful types of +variables. See the :ref:`built-in types <lang-built-in-types>` page +for more information. + +Here are a few examples of declaring variables of different types:: + + int lightSensVal; + char currentLetter; + unsigned long speedOfLight = 186000UL; + char errorMessage = {"choose another option"}; // see string + +Naming Variables +---------------- + +The rules for naming a variable are simple. Names for variables can +contain letters, numbers, and underscores (the underscore is the +:kbd:`_` character), and cannot begin with a number. So +``temperature_reading``, ``tempReading``, ``tempReading1``, and +``tempReading2`` are all valid variable names, but ``4_temp_readings`` +is not, because it begins with a number. + +You cannot choose a name for a variable that is one of the C++ +:ref:`keywords <lang-keywords>`. + +Variable names are case-sensitive, so "tempreading" and "tempReading" +are different variables. However, it is very bad style to write code +that chooses variables which are the same up to case. + +You should give your variables descriptive names, so as to make your +code more readable. Variable names like ``tiltSensor`` or +``pushButton`` help you (and anyone else reading your code) understand +what the variable represents. Variable names like ``var`` or +``value``, on the other hand, do little to make your code readable. + +.. _lang-variables-scope: + +Variable Scope +-------------- + +An important choice that programmers face is where (in the program +text) to declare variables. The specific place that variables are +declared influences how various functions in a program will "see" the +variable. This is called variable *scope*. See the :ref:`scope +reference <lang-scope>` for more information. + +.. _lang-variables-initializing: + +Initializing Variables +---------------------- + +Variables may be *initialized* (assigned a starting value) when they +are declared or not. It is always good programming practice however to +double check that a variable has valid data in it before it is used. +Using a variable before you give it a value is a common source of +bugs. + +.. _lang-variables-rollover: + +Variable Rollover +----------------- + +Every (numeric) type has a valid *range*. The range of a type is the +smallest and largest value that a variable of that type can store. +For example, the :ref:`int <lang-int>` type has a range of +-2,147,483,648 to 2,147,483,647 [#frange]_. + +When variables are made to exceed their range's maximum value, they +"roll over" back to their minimum value. Note that this happens in +both directions. It's like in the game *Pac-Man* -- when Pac-Man goes +past the right edge of the screen, he reappears on the left, and when +he goes past the left side of the screen, he reappears on the right:: + + int x; + x = -2,147,483,648; + x = x - 1; // x now contains -2,147,483,647; rolled over "left to right" + + x = 2,147,483,647; + x = x + 1; // x now contains -2,147,483,648; rolled over "right to left" + +Each numeric type's reference page includes its range. See the +:ref:`built-in types <lang-built-in-types>` reference for links to each +type's reference page. + +Using Variables +--------------- + +Once variables have been declared, they are given values using the +:ref:`assignment operator <lang-assignment>`, which is a single equals +sign, ``=``. The assignment operator tells the program to store the +value on the right side of the equals sign into the variable on the +left side:: + + inputVariable1 = 7; // sets variable named inputVariable1 to 7 + inputVariable2 = analogRead(2); // sets variable named inputVariable2 to + // the (digitized) input voltage read from + // analog pin #2 + +Once a variable has been set (assigned a value), you can test its +value to see if it meets certain conditions, or you can use its value +directly. For instance, the following code tests whether the +inputVariable2 is less than 100, then sets a delay based on +inputVariable2 (which, at that point, is at least 100):: + + if (inputVariable2 < 100) { + inputVariable2 = 100; + } + + delay(inputVariable2); + +See Also +-------- + +- :ref:`lang-scope` +- :ref:`lang-built-in-types` + +.. rubric:: Footnotes + +.. [#frange] This range might seem a little weird at first. The + reasons for this range of values have to do with the fact that an + ``int`` occupies 32 bits of memory, and the facts :: + + 2^31 = -2,147,483,648 + 2^31 - 1 = 2,147,483,647 + + + Why 2^31 instead of 2^32? Well, that has to do with `how ints are + (usually) stored + <http://en.wikipedia.org/wiki/Two%27s_complement>`_ on computers. + + +.. include:: cc-attribution.txt + diff --git a/docs/source/lang/cpp/void.rst b/docs/source/lang/cpp/void.rst new file mode 100644 index 0000000..88c9c64 --- /dev/null +++ b/docs/source/lang/cpp/void.rst @@ -0,0 +1,33 @@ +.. highlight:: cpp + +.. _lang-void: + +``void`` +======== + +.. cpp:type:: void + + The ``void`` keyword is used in function declarations. It indicates + that the function is expected to return no information to the + function from which it was called, or that it expects no arguments + from its caller. + +Example +------- + +:: + + // actions are performed in the functions "setup" and "loop" + // but no information is reported to the larger program + + void setup() { + // ... + } + + void loop() { + // ... + } + +.. TODO doc page on function declaration? + +.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/while.rst b/docs/source/lang/cpp/while.rst new file mode 100644 index 0000000..9047d05 --- /dev/null +++ b/docs/source/lang/cpp/while.rst @@ -0,0 +1,38 @@ +.. highlight:: cpp + +.. _lang-while: + +``while`` +========= + +Syntax +------ + +:: + + while (expression) { + // block of code + } + +Description +----------- + +``while`` loops will repeat the statements inside their associated +block of code until the expression inside the parentheses becomes +:ref:`false <lang-constants-false>`. Something must change the tested +expressions' value, or the ``while`` loop will never exit. This could +be in your code, such as an incremented variable, or an external +condition, such as testing a sensor. + +Example +------- + +:: + + var = 0; + while(var < 200) { + // do something repetitive 200 times + var++; + } + +.. include:: cc-attribution.txt diff --git a/docs/source/arduino/notone.rst b/docs/source/lang/unimplemented/notone.rst index 4390b52..485c9c5 100644 --- a/docs/source/arduino/notone.rst +++ b/docs/source/lang/unimplemented/notone.rst @@ -1,4 +1,4 @@ -.. _arduino-notone: +.. _lang-notone: noTone() ======== @@ -45,3 +45,6 @@ See also - `tone <http://arduino.cc/en/Reference/Tone>`_ () + + +.. include:: /lang/cc-attribution.txt diff --git a/docs/source/arduino/pulsein.rst b/docs/source/lang/unimplemented/pulsein.rst index 568d992..2b52428 100644 --- a/docs/source/arduino/pulsein.rst +++ b/docs/source/lang/unimplemented/pulsein.rst @@ -1,4 +1,4 @@ -.. _arduino-pulsein: +.. _lang-pulsein: pulseIn() ========= @@ -61,19 +61,22 @@ Example :: - - + + int pin = 7; unsigned long duration; - + void setup() { pinMode(pin, INPUT); } - + void loop() { duration = pulseIn(pin, HIGH); } + + +.. include:: /lang/cc-attribution.txt diff --git a/docs/source/arduino/shiftout.rst b/docs/source/lang/unimplemented/shiftout.rst index 2277cf1..ff3852f 100644 --- a/docs/source/arduino/shiftout.rst +++ b/docs/source/lang/unimplemented/shiftout.rst @@ -1,4 +1,4 @@ -.. _arduino-shiftout: +.. _lang-shiftout: shiftOut() ========== @@ -72,16 +72,16 @@ requires a two step operation to output values larger than 255. // Do this for MSBFIRST serial int data = 500; // shift out highbyte - shiftOut(dataPin, clock, MSBFIRST, (data >> 8)); + shiftOut(dataPin, clock, MSBFIRST, (data >> 8)); // shift out lowbyte shiftOut(data, clock, MSBFIRST, data); - + // Or do this for LSBFIRST serial data = 500; // shift out lowbyte - shiftOut(dataPin, clock, LSBFIRST, data); - // shift out highbyte - shiftOut(dataPin, clock, LSBFIRST, (data >> 8)); + shiftOut(dataPin, clock, LSBFIRST, data); + // shift out highbyte + shiftOut(dataPin, clock, LSBFIRST, (data >> 8)); @@ -102,32 +102,35 @@ Example // Notes : Code for using a 74HC595 Shift Register // // : to count from 0 to 255 // //**************************************************************** - + //Pin connected to ST_CP of 74HC595 int latchPin = 8; //Pin connected to SH_CP of 74HC595 int clockPin = 12; ////Pin connected to DS of 74HC595 int dataPin = 11; - + void setup() { //set pins to output because they are addressed in the main loop pinMode(latchPin, OUTPUT); pinMode(clockPin, OUTPUT); pinMode(dataPin, OUTPUT); } - + void loop() { //count up routine for (int j = 0; j < 256; j++) { //ground latchPin and hold low for as long as you are transmitting digitalWrite(latchPin, LOW); - shiftOut(dataPin, clockPin, LSBFIRST, j); - //return the latch pin high to signal chip that it + shiftOut(dataPin, clockPin, LSBFIRST, j); + //return the latch pin high to signal chip that it //no longer needs to listen for information digitalWrite(latchPin, HIGH); delay(1000); } - } + } + + +.. include:: /lang/cc-attribution.txt diff --git a/docs/source/lang/unimplemented/stringclass.rst b/docs/source/lang/unimplemented/stringclass.rst new file mode 100644 index 0000000..b893e83 --- /dev/null +++ b/docs/source/lang/unimplemented/stringclass.rst @@ -0,0 +1,6 @@ +.. _lang-stringclass: + +String Class +============ + +.. include:: /lang/cc-attribution.txt diff --git a/docs/source/arduino/stringobject.rst b/docs/source/lang/unimplemented/stringobject.rst index ffee295..e47ed7e 100644 --- a/docs/source/arduino/stringobject.rst +++ b/docs/source/lang/unimplemented/stringobject.rst @@ -1,4 +1,4 @@ -.. _arduino-stringobject: +.. _lang-stringobject: String ====== @@ -6,12 +6,11 @@ String Description ----------- -The String class, part of the core as of version 0019, allows you -to use and manipulate strings of text in more complex ways than -`character arrays <http://arduino.cc/en/Reference/String>`_ do. You -can concatenate Strings, append to them, search for and replace -substrings, and more. It takes more memory than a simple character -array, but it is also more useful. +The String class, part of the core as of version 0019, allows you to +use and manipulate strings of text in more complex ways than character +arrays do. You can concatenate Strings, append to them, search for and +replace substrings, and more. It takes more memory than a simple +character array, but it is also more useful. @@ -81,8 +80,10 @@ See Also -------- -- `string <http://arduino.cc/en/Reference/String>`_: character - arrays +- `Character array strings <http://arduino.cc/en/Reference/String>`_ - `Variable Declaration <http://arduino.cc/en/Reference/VariableDeclaration>`_ + + +.. include:: /lang/cc-attribution.txt diff --git a/docs/source/arduino/tone.rst b/docs/source/lang/unimplemented/tone.rst index c7b1e44..f83bf6b 100644 --- a/docs/source/arduino/tone.rst +++ b/docs/source/lang/unimplemented/tone.rst @@ -1,4 +1,4 @@ -.. _arduino-tone: +.. _lang-tone: tone() ====== @@ -72,7 +72,10 @@ See also - `Tutorial:Pitch follower <http://arduino.cc/en/Tutorial/Tone2>`_ - `Tutorial:Simple Keyboard <http://arduino.cc/en/Tutorial/Tone3>`_ - `Tutorial: multiple tones <http://arduino.cc/en/Tutorial/Tone4>`_ - + - `Tutorial: PWM <http://arduino.cc/en/Tutorial/PWM>`_ + + +.. include:: /lang/cc-attribution.txt diff --git a/docs/source/language-index.rst b/docs/source/language-index.rst new file mode 100644 index 0000000..e160e2b --- /dev/null +++ b/docs/source/language-index.rst @@ -0,0 +1,40 @@ +.. _language-index: + +======================= +Complete Language Index +======================= + +This is the index of Maple's :ref:`language reference +<language-lang-docs>` documentation. The "Maple API" column provides +API references for documented libmaple functionality. The "C++ for +Maple".. pages are adaptations of the Arduino C++ documentation to the +.. Maple, and are intended as a minimal reference/refresher for +.. programmers familiar with the Arduino language. + +.. _index-language-index-cpp: +.. _index-language-index-api: + ++----------------------------------+------------------------------------+ +| Maple API | C++ for Maple | +| | | ++==================================+====================================+ +| | | +| .. toctree:: | .. toctree:: | +| :maxdepth: 1 | :maxdepth: 1 | +| :glob: | :glob: | +| | | +| lang/api/* | lang/cpp/* | +| | | ++----------------------------------+------------------------------------+ + +.. Unimplemented in libmaple or not part of current release: + +.. toctree:: + :hidden: + + lang/unimplemented/notone.rst + lang/unimplemented/pulsein.rst + lang/unimplemented/shiftout.rst + lang/unimplemented/stringclass.rst + lang/unimplemented/stringobject.rst + lang/unimplemented/tone.rst diff --git a/docs/source/language.rst b/docs/source/language.rst index 5a2efad..018eb8c 100644 --- a/docs/source/language.rst +++ b/docs/source/language.rst @@ -9,16 +9,6 @@ The Maple can be programmed in the `Wiring <http://www.wiring.org.co/reference/>`_ language, which is the same language used to program the `Arduino <http://arduino.cc/>`_ boards. -Please see the extensive `language reference -<http://arduino.cc/en/Reference/HomePage>`_ on the Arduino webpage for -more information, or follow a direct link below. - -.. warning:: - - The Arduino boards have different sizes for data types, so don't - trust their documentation for how many bytes an ``int``, ``long``, - etc. take up. The sizes of each data type on the Maple are given - in the :ref:`table below <language-arduino-docs>`. C or C++ programmers curious about the differences between the Wiring language and C++ may wish to skip to the @@ -52,284 +42,257 @@ Unique Maple Additions #define DEBUG_LEVEL DEBUG_NONE - before including either wirish or libmaple. In this case, all + before including either wirish.h or libmaple.h. In this case, all assertions will pass without any lost clock cycles. Note that this will **not work in the IDE**; even with this definition, assertions will still be enabled. -.. _language-arduino-docs: - -Arduino Documentation Links ---------------------------- - -(This table was copied from http://arduino.cc/en/Reference/Extended). - -+------------------------------------+------------------------------------+-----------------------------------------+ -| Structure | Variables | Functions | -| | | | -+====================================+====================================+=========================================+ -| |**Constants** |**Digital I/O** | -|* `setup()`_ | | | -| |* `HIGH`_ | `LOW`_ |* `pinMode()`_ | -|* `loop()`_ | | | -| |* `INPUT`_ | `OUTPUT`_ |* `digitalWrite()`_ | -| | | | -|**Control Structures** |* `true`_ | `false`_ |* `digitalRead()`_ | -| | | | -|* `if`_ |* `integer constants`_ | | -| | |**Analog I/O** | -|* `if...else`_ |* `floating point constants`_ | | -| | |* `analogReference()`_ | -|* `for`_ | | | -| |**Data Types** |* `analogRead()`_ | -|* `switch/case`_ | | | -| |Primitive data types on the Maple |* `analogWrite()`_ - PWM | -|* `while`_ |have different sizes than on the | | -| |Arduino, since the Maple has a full | | -|* `do...while`_ |32-bit processor. The size of each |**Advanced I/O** | -| |such type on the Maple is given | | -|* `break`_ |below. |* `tone()`_ | -| | | | -|* `continue`_ |The ``word`` type is (deliberately) |* `noTone()`_ | -| |:ref:`not supported | | -|* `return`_ |<language-no-word>`. |* `shiftOut()`_ | -| | | | -|* `goto`_ |* `void`_ |* `pulseIn()`_ | -| | | | -| |* `boolean`_ (1 byte) | | -|**Further syntax** | |**Time** | -| |* `char`_ (1 byte) | | -|* `;`_ (semicolon) | |* `millis()`_ | -| |* `unsigned char`_ (1 byte) | | -|* `{}`_ (curly braces) | |* `micros()`_ | -| |* `byte`_ (1 byte) | | -|* `//`_ (single line comment) | |* `delay()`_ | -| |* `int`_ (4 bytes) | | -|* `/\* \*/`_ (multi-line comment) | |* `delayMicroseconds()`_ | -| |* `unsigned int`_ (4 bytes) | | -|* `#define`_ | | | -| |* `long`_ (8 bytes) |**Math** | -|* `#include`_ | | | -| |* `unsigned long`_ (8 bytes) |* `min()`_ | -| | | | -|**Arithmetic Operators** |* `float`_ (4 bytes) |* `max()`_ | -| | | | -|* `=`_ (assignment operator) |* `double`_ (8 bytes) |* `abs()`_ | -| | | | -|* `+`_ (addition) |* `string`_ |* `constrain()`_ | -| | | | -|* `-`_ (subtraction) |* `array`_ |* `map()`_ | -| | | | -|* `*`_ (multiplication) | |* `pow()`_ | -| |**Conversion** | | -|* `/`_ (division) | |* `sqrt()`_ | -| |* `char()`_ | | -|* `%`_ (modulo) | | | -| |* `byte()`_ |**Trigonometry** | -| | | | -|**Comparison Operators** |* `int()`_ |* `sin()`_ | -| | | | -|* `==`_ (equal to) |* `word()`_ |* `cos()`_ | -| | | | -|* `!=`_ (not equal to) |* `long()`_ |* `tan()`_ | -| | | | -|* `<`_ (less than) |* `float()`_ | | -| | |**Random Numbers** | -|* `>`_ (greater than) | | | -| |**Variable Scope & Qualifiers** |* `randomSeed()`_ | -|* `<=`_ (less than or equal to) | | | -| |* `variable scope`_ |* `random()`_ | -|* `>=`_ (greater than or equal to) | | | -| |* `static`_ | | -| | |**Bits and Bytes** | -|**Boolean Operators** |* `volatile`_ | | -| | |* `lowByte()`_ | -|* `&&`_ (and) |* `const`_ | | -| | |* `highByte()`_ | -|* `||`_ (or) | | | -| |**Utilities** |* `bitRead()`_ | -|* `!`_ (not) | | | -| |* `sizeof()`_ (sizeof operator) |* `bitWrite()`_ | -| | | | -|**Pointer Access Operators** | |* `bitSet()`_ | -| | | | -|* `* dereference operator`_ | |* `bitClear()`_ | -| | | | -|* `& reference operator`_ | |* `bit()`_ | -| | | | -| | | | -|**Bitwise Operators** | |**External Interrupts** | -| | | | -|* `&`_ (bitwise and) | |For more information on external | -| | |interrupts on Maple, see | -|* `|`_ (bitwise or) | |`our reference page`_. | -| | | | -|* `^`_ (bitwise xor) | | | -| | |* `attachInterrupt()`_ | -|* `~`_ (bitwise not) | | | -| | |* `detachInterrupt()`_ | -|* `<<`_ (shift left) | | | -| | | | -|* `>>`_ (shift right) | |**Interrupts** | -| | | | -| | |* `interrupts()`_ | -|**Compound Operators** | | | -| | |* `noInterrupts()`_ | -|* `++`_ (increment) | | | -| | | | -|* `- -`_ (decrement) | |**Communication** | -| | | | -|* `+=`_ (compound addition) | |* `Serial`_ | -| | | | -|* `-=`_ (compound subtraction) | |**Looking for something else?** | -| | | | -|* `*=`_ (compound multiplication) | |See the :ref:`libraries` page for | -| | |interfacing with particular types of | -|* `/=`_ (compound division) | |hardware. Try the list of | -| | |`community-contributed code`_. Maple | -|* `&=`_ (compound bitwise and) | |links against `newlib`_ and allows the | -| | |use of any of its functions; see its | -|* `|=`_ (compound bitwise or) | |documentation for more details. | -| | | | -+------------------------------------+------------------------------------+-----------------------------------------+ +.. _language-lang-docs: + +Maple Language Reference +------------------------ + +The following table summarizes the available core language features. +A more exhaustive index is available at the :ref:`language-index`. + ++--------------------------------------------+----------------------------------------------+---------------------------------------------------+ +| Structure | Variables | Functions | +| | | | ++============================================+==============================================+===================================================+ +|* :ref:`setup() <lang-setup>` |**Constants** |**Digital I/O** | +| | | | +|* :ref:`loop() <lang-loop>` |* :ref:`HIGH <lang-constants-high>` | |* :ref:`pinMode() <lang-pinmode>` | +| | :ref:`LOW <lang-constants-low>` | | +| | |* :ref:`digitalWrite() <lang-digitalwrite>` | +|**Control Structures** |* :ref:`INPUT <lang-constants-input>` | | | +| | :ref:`OUTPUT <lang-constants-output>` |* :ref:`digitalRead() <lang-digitalread>` | +|* :ref:`if/else <lang-if>` | | | +| |* :ref:`true <lang-constants-true>` | |* :ref:`togglePin() <lang-togglepin>` | +|* :ref:`for <lang-for>` | :ref:`false <lang-constants-false>` | | +| | |* :ref:`toggleLED() <lang-toggleled>` | +|* :ref:`switch/case <lang-switchcase>` |* :ref:`BOARD_LED_PIN <lang-constants-led>` | | | +| | :ref:`BOARD_BUTTON_PIN <lang-constants-but>`|* :ref:`isButtonPressed() <lang-isbuttonpressed>` | +|* :ref:`while <lang-while>` | | | +| |* :ref:`Constants |* :ref:`waitForButtonPress() | +|* :ref:`do...while <lang-dowhile>` | <lang-constants>` (:ref:`integers | <lang-waitforbuttonpress>` | +| | <lang-constants-integers>`, :ref:`floating | | +|* :ref:`break <lang-break>` | point <lang-constants-fp>`) |**Analog I/O** | +| | | | +|* :ref:`continue <lang-continue>` |**Data Types** |* :ref:`analogRead() <lang-analogread>` | +| | | | +|* :ref:`return <lang-return>` | The size of each datatype, in bytes, is |* :ref:`pwmWrite() <lang-pwmwrite>` | +| | given in parentheses where appropriate. | (:ref:`analogWrite() <lang-analogwrite>` is | +|* :ref:`goto <lang-goto>` | | also available, though its use is discouraged) | +| | *Note*: The ``word`` type is (deliberately) | | +| | :ref:`not supported <language-no-word>`. | | +|**Further syntax** | |**Advanced I/O** | +| |* :ref:`void <lang-void>` | | +|* :ref:`; (semicolon) <lang-semicolon>` | |* tone(): TODO | +| |* :ref:`boolean <lang-boolean>` (1 byte) | | +|* :ref:`{} (curly braces) | |* noTone(): TODO | +| <lang-curly-braces>` |* :ref:`char <lang-char>` (1 byte) | | +| | |* shiftOut(): TODO | +|* :ref:`// (single-line comment) |* :ref:`unsigned char | | +| <lang-comments-singleline>` | <lang-unsignedchar>` (1 byte) |* pulseIn(): TODO | +| | | | +|* :ref:`/\* \*/ (multi-line comment) |* :ref:`byte <lang-byte>` (1 byte) | | +| <lang-comments-multiline>` | |**Time** | +| |* :ref:`int <lang-int>` (4 bytes) | | +|* :ref:`#define <lang-define>` | |* :ref:`millis() <lang-millis>` | +| |* :ref:`unsigned int <lang-unsignedint>` | | +|* :ref:`#include <lang-include>` | (4 bytes) |* :ref:`micros() <lang-micros>` | +| | | | +| |* :ref:`long <lang-long>` (8 bytes) |* :ref:`delay() <lang-delay>` | +|**Arithmetic Operators** | | | +| |* :ref:`unsigned long <lang-unsignedlong>` |* :ref:`delayMicroseconds() | +|* :ref:`= <lang-assignment>` | (8 bytes) | <lang-delaymicroseconds>` | +| (assignment operator) | | | +| |* :ref:`float <lang-float>` (4 bytes) | | +|* :ref:`+ <lang-arithmetic>` (addition) | |**Math** | +| |* :ref:`double <lang-double>` (8 bytes) | | +|* :ref:`- <lang-arithmetic>` | |* :ref:`min() <lang-min>` | +| (subtraction) |* :ref:`Strings <lang-string>` | | +| | |* :ref:`max() <lang-max>` | +|* :ref:`* <lang-arithmetic>` |* :ref:`Arrays <lang-array>` | | +| (multiplication) | |* :ref:`abs() <lang-abs>` | +| |* :ref:`enum <lang-enum>` | | +|* :ref:`/ <lang-arithmetic>` (division) | |* :ref:`constrain() <lang-constrain>` | +| |* :ref:`Numeric types <lang-built-in-types>` | | +|* :ref:`% <lang-modulo>` (modulo) | |* :ref:`map() <lang-map>` | +| |**Conversion** | | +| | |* :ref:`pow() <lang-pow>` | +|**Comparison Operators** |* :ref:`char() <lang-charcast>` | | +| | |* :ref:`sqrt() <lang-sqrt>` | +|* :ref:`== <lang-comparison>` (equal to) |* :ref:`byte() <lang-bytecast>` | | +| | | | +|* :ref:`\!= <lang-comparison>` |* :ref:`int() <lang-intcast>` |**Trigonometry** | +| (not equal to) | | | +| |* :ref:`long() <lang-longcast>` |* :ref:`sin() <lang-sin>` | +|* :ref:`< <lang-comparison>` (less than) | | | +| |* :ref:`float() <lang-floatcast>` |* :ref:`cos() <lang-cos>` | +|* :ref:`> <lang-comparison>` | | | +| (greater than) |* :ref:`double() <lang-doublecast>` |* :ref:`tan() <lang-tan>` | +| | | | +|* :ref:`<= <lang-comparison>` | | | +| (less than or equal to) |**Variable Scope & Qualifiers** |**Random Numbers** | +| | | | +|* :ref:`>= <lang-comparison>` |* :ref:`variables <lang-variables>`, |* :ref:`randomSeed() <lang-randomseed>` | +| (greater than or equal to) | :ref:`scope <lang-variables-scope>` | | +| | |* :ref:`random() <lang-random>` | +| |* :ref:`static <lang-static>` | | +|**Boolean Operators** | | | +| |* :ref:`volatile <lang-volatile>` |**Bits and Bytes** | +|* :ref:`&& <lang-boolean-and>` (and) | | | +| |* :ref:`const <lang-const>` |* :ref:`lowByte() <lang-lowbyte>` | +|* :ref:`|| <lang-boolean-or>` (or) | | | +| | |* :ref:`highByte() <lang-highbyte>` is | +|* :ref:`\! <lang-boolean-not>` (not) |**Utilities** | provided, though its use is discouraged. | +| | | | +| |* :ref:`sizeof() <lang-sizeof>` |* :ref:`bitRead() <lang-bitread>` | +|**Pointer Operators** | | | +| | |* :ref:`bitWrite() <lang-bitwrite>` | +|* :ref:`* dereference operator | | | +| <lang-pointer>` | |* :ref:`bitSet() <lang-bitset>` | +| | | | +|* :ref:`& reference operator | |* :ref:`bitClear() <lang-bitclear>` | +| <lang-pointer>` | | | +| | |* :ref:`bit() <lang-bit>` | +| | | | +|**Bitwise Operators** | | | +| | |**External Interrupts** | +|* :ref:`& <lang-bitwisemath-and>` | | | +| (bitwise and) | |* :ref:`Reference Page <external-interrupts>` | +| | | | +|* :ref:`| <lang-bitwisemath-or>` | |* :ref:`attachInterrupt() | +| (bitwise or) | | <lang-attachinterrupt>` | +| | | | +|* :ref:`^ <lang-bitwisemath-xor>` | |* :ref:`detachInterrupt() | +| (bitwise xor) | | <lang-detachinterrupt>` | +| | | | +|* :ref:`~ <lang-bitwisemath-not>` | | | +| (bitwise not) | |**Interrupts** | +| | | | +|* :ref:`\<\< <lang-bitshift>` | |* :ref:`interrupts() <lang-interrupts>` | +| (shift left) | | | +| | |* :ref:`noInterrupts() <lang-nointerrupts>` | +|* :ref:`>> <lang-bitshift>` | | | +| (shift right) | | | +| | |**Communication** | +| | | | +|**Compound Operators** | |* :ref:`SerialUSB <lang-serialusb>` | +| | | | +|* :ref:`++ <lang-increment>` | |* :ref:`Serial <lang-serial>` | +| (increment) | | | +| | |**Looking for something else?** | +|* :ref:`- - <lang-increment>` | | | +| (decrement) | | See the :ref:`libraries` page for interfacing with| +| | | particular types of hardware. Maple links | +|* :ref:`+= <lang-compoundarithmetic>` | | against `newlib <http://sourceware.org/newlib/>`_ | +| (compound add) | | and allows the use of any of its functions; see | +| | | its documentation for more details. | +|* :ref:`-= | | | +| <lang-compoundarithmetic>` (compound | | | +| subtract) | | | +| | | | +|* :ref:`*= | | | +| <lang-compoundarithmetic>` (compound | | | +| multiply) | | | +| | | | +|* :ref:`/= | | | +| <lang-compoundarithmetic>` (compound | | | +| divide) | | | +| | | | +|* :ref:`&= | | | +| <lang-compoundbitwise>` (compound | | | +| bitwise and) | | | +| | | | +|* :ref:`|= | | | +| <lang-compoundbitwise>` (compound | | | +| bitwise or) | | | +| | | | +|**Keywords** | | | +| | | | +|* :ref:`C++ Keywords <lang-keywords>` | | | +| | | | +| | | | ++--------------------------------------------+----------------------------------------------+---------------------------------------------------+ + +.. _language-missing-features: + +Missing Arduino Features +------------------------ + +.. _langage-missing-analogreference: + +**analogReference()** + + It is not possible to implement this function on the Maple + hardware. It will be possible on the upcoming Maple Native. .. _language-no-word: -.. note:: - - The ``word`` data type is not supported on the Maple. This is by - choice. - - We decided not to include it because, while the Maple has 32-bit - words, the word size on an Arduino board is only 16 bits, and code - that uses the ``word`` type is likely to rely on that fact. - - By not supporting ``word``, you'll get a compile error when porting - Arduino code to your Maple instead of potentially weird, - hard-to-debug runtime behavior. - - If you're porting over Arduino code and really want ``word``, you - can put the following at the top of the file you're porting:: - - typedef uint16 word; - -.. _if: http://arduino.cc/en/Reference/If -.. _if...else: http://arduino.cc/en/Reference/Else -.. _for: http://arduino.cc/en/Reference/For -.. _switch/case: http://arduino.cc/en/Reference/SwitchCase -.. _while: http://arduino.cc/en/Reference/While -.. _do...while: http://arduino.cc/en/Reference/DoWhile -.. _break: http://arduino.cc/en/Reference/Break -.. _continue: http://arduino.cc/en/Reference/Continue -.. _return: http://arduino.cc/en/Reference/Return -.. _goto: http://arduino.cc/en/Reference/Goto - -.. _;: http://arduino.cc/en/Reference/SemiColon -.. _{}: http://arduino.cc/en/Reference/Braces -.. _//: http://arduino.cc/en/Reference/Comments -.. _/\* \*/: http://arduino.cc/en/Reference/Comments -.. _#define: http://arduino.cc/en/Reference/Define -.. _#include: http://arduino.cc/en/Reference/Include - -.. _=: http://arduino.cc/en/Reference/Assignment -.. _+: http://arduino.cc/en/Reference/Arithmetic -.. _-: http://arduino.cc/en/Reference/Arithmetic -.. _*: http://arduino.cc/en/Reference/Arithmetic -.. _/: http://arduino.cc/en/Reference/Arithmetic -.. _%: http://arduino.cc/en/Reference/Modulo - -.. _==: http://arduino.cc/en/Reference/If -.. _!=: http://arduino.cc/en/Reference/If -.. _<: http://arduino.cc/en/Reference/If -.. _>: http://arduino.cc/en/Reference/If -.. _<=: http://arduino.cc/en/Reference/If -.. _>=: http://arduino.cc/en/Reference/If - -.. _&&: http://arduino.cc/en/Reference/Boolean -.. _||: http://arduino.cc/en/Reference/Boolean -.. _!: http://arduino.cc/en/Reference/Boolean - -.. _* dereference operator: http://arduino.cc/en/Reference/Pointer -.. _& reference operator: http://arduino.cc/en/Reference/Pointer - -.. _&: http://arduino.cc/en/Reference/BitwiseAnd -.. _|: http://arduino.cc/en/Reference/BitwiseAnd -.. _^: http://arduino.cc/en/Reference/BitwiseAnd -.. _~: http://arduino.cc/en/Reference/BitwiseXorNot -.. _<<: http://arduino.cc/en/Reference/Bitshift -.. _>>: http://arduino.cc/en/Reference/Bitshift - -.. _++: http://arduino.cc/en/Reference/Increment -.. FIXME can't freaking get two hyphens to show up! sphinx turns "--" -.. into an endash, whatever, fine, try to escape like "\-\-", that -.. ALSO becomes endash (!@#$), damn, well, maybe someone else is -.. eating my slash, try "\\-\\-", nope, that turns into a motherfing -.. \-\-. i hate everything. -.. _- -: http://arduino.cc/en/Reference/Increment -.. _+=: http://arduino.cc/en/Reference/IncrementCompound -.. _-=: http://arduino.cc/en/Reference/IncrementCompound -.. _*=: http://arduino.cc/en/Reference/IncrementCompound -.. _/=: http://arduino.cc/en/Reference/IncrementCompound -.. _&=: http://arduino.cc/en/Reference/BitwiseCompound -.. _|=: http://arduino.cc/en/Reference/BitwiseCompound - -.. _HIGH: http://arduino.cc/en/Reference/Constants -.. _LOW: http://arduino.cc/en/Reference/Constants -.. _INPUT: http://arduino.cc/en/Reference/Constants -.. _OUTPUT: http://arduino.cc/en/Reference/Constants -.. _true: http://arduino.cc/en/Reference/Constants -.. _false: http://arduino.cc/en/Reference/Constants -.. _integer constants: http://arduino.cc/en/Reference/IntegerConstants -.. _floating point constants: http://arduino.cc/en/Reference/Fpconstants - -.. _void: http://arduino.cc/en/Reference/Void -.. _boolean: http://arduino.cc/en/Reference/BooleanVariables -.. _char: http://arduino.cc/en/Reference/Char -.. _unsigned char: http://arduino.cc/en/Reference/UnsignedChar -.. _byte: http://arduino.cc/en/Reference/Byte -.. _int: http://arduino.cc/en/Reference/Int -.. _unsigned int: http://arduino.cc/en/Reference/UnsignedInt -.. _word: http://arduino.cc/en/Reference/Word -.. _long: http://arduino.cc/en/Reference/Long -.. _unsigned long: http://arduino.cc/en/Reference/UnsignedLong -.. _float: http://arduino.cc/en/Reference/Float -.. _double: http://arduino.cc/en/Reference/Double -.. _string: http://arduino.cc/en/Reference/String -.. _array: http://arduino.cc/en/Reference/Array - -.. _char(): http://arduino.cc/en/Reference/CharCast -.. _byte(): http://arduino.cc/en/Reference/ByteCast -.. _int(): http://arduino.cc/en/Reference/IntCast -.. _word(): http://arduino.cc/en/Reference/WordCast -.. _long(): http://arduino.cc/en/Reference/LongCast -.. _float(): http://arduino.cc/en/Reference/FloatCast - -.. _variable scope: http://arduino.cc/en/Reference/Scope -.. _static: http://arduino.cc/en/Reference/Static -.. _volatile: http://arduino.cc/en/Reference/Volatile -.. _const: http://arduino.cc/en/Reference/Const -.. _sizeof(): http://arduino.cc/en/Reference/Sizeof - -.. Links for the standard Arduino built-in functions are included as -.. part of the standard epilog. +**word** + + Readers familiar with the Arduino environment may notice that the + ``word`` datatype is missing from the above table's list of data + types. We chose **not to provide** the ``word`` data type on the + Maple. If you want a 16-bit unsigned integer, use the ``uint16`` + type instead. + + While the Maple has 32-bit words, the word size on an Arduino + board is only 16 bits, and code that uses the ``word`` type is + likely to rely on that fact. + + By not supporting ``word``, you'll get a compile error when + porting Arduino code to the Maple instead of potentially weird, + hard-to-debug runtime behavior. + + If you really must have ``word``, you can include the following + ``typedef`` in your program:: + + typedef uint16 word; + +Unimplemented Arduino Features +------------------------------ + +The following Wiring/Arduino features are currently unimplemented on +the Maple. However, they will be present in future versions: + +- `noTone() <http://www.arduino.cc/en/Reference/NoTone>`_ +- `pulseIn() <http://www.arduino.cc/en/Reference/PulseIn>`_ +- `shiftOut() <http://www.arduino.cc/en/Reference/ShiftOut>`_ +- `String <http://arduino.cc/en/Reference/StringObject>`_ +- `tone() <http://www.arduino.cc/en/Reference/Tone>`_ + .. _our reference page: http://leaflabs.com/docs/external-interrupts/ -.. _Serial: http://arduino.cc/en/Reference/Serial -.. _community-contributed code: http://www.arduino.cc/playground/Main/GeneralCodeLibrary .. _newlib: http://sourceware.org/newlib/ +.. _cpp-for-maple: + +C++ for Maple +-------------- + +If you haven't programmed in C++, or if you just need to jog your +memory, you may want to check out our :ref:`Language Index +<language-index>`. It provides some introductory coverage of +programming ideas and C++. .. _arduino_c_for_c_hackers: -Note for C/C++ Programmers --------------------------- +Note for C/C++ Hackers +---------------------- This is a note for programmers comfortable with C or C++ (although, you C programmers should remember that `C++ is not a superset of C <http://en.wikipedia.org/wiki/Compatibility_of_C_and_C%2B%2B>`_) who want a better understanding of the differences between C++ and the Wiring language. The good news is that the differences are relatively -few. +few; Wiring is just a thin wrapper around C++. + +Some potentially better news is that the Maple can be programmed using +a :ref:`standard Unix toolchain <unix-toolchain>`, so if you'd rather +stick with :command:`gcc`, :command:`make`, and friends, you can. A *sketch* is the IDE's notion of a project; it consists of one or more files written in the Wiring language, which is mostly the same as @@ -359,8 +322,8 @@ The Wiring language also does not require you to define your own are required to define two functions, ``setup`` and ``loop``, with type signatures :: - void setup(void) - void loop(void) + void setup(void); + void loop(void); Once a sketch is uploaded to a Maple and begins to run, ``setup()`` is called once, and then ``loop()`` is called repeatedly. The IDE @@ -394,7 +357,7 @@ method, which behaves roughly like:: while (true) loop(); } -(The truth is a little bit more complicated, but not by much). +(The truth is a little bit more complicated, but not by much). As an example, consider a sketch with two files. The first file contains ``setup()`` and ``loop()``:: @@ -407,9 +370,7 @@ contains ``setup()`` and ``loop()``:: } void loop() { - static int toggle = 0; - toggle ^= 1; - digitalWrite(the_pin, toggle); + togglePin(the_pin); } The second file contains the (not very useful) implementation for @@ -429,9 +390,7 @@ Then the results of the concatenation process might be :: } void loop() { - static int toggle = 0; - toggle ^= 1; - digitalWrite(the_pin, toggle); + togglePin(the_pin); } int choose_a_pin(void); @@ -456,9 +415,7 @@ Which could plausibly be turned into the final source file :: } void loop() { - static int toggle = 0; - toggle ^= 1; - digitalWrite(the_pin, toggle); + togglePin(the_pin); } int choose_a_pin(void); @@ -482,7 +439,6 @@ Recommended Reading * `newlib Documentation <http://sourceware.org/newlib/>`_ * STMicro documentation for STM32F103RB microcontroller: - * `All documents <http://www.st.com/mcu/devicedocs-STM32F103RB-110.html>`_ * `Datasheet <http://www.st.com/stonline/products/literature/ds/13587.pdf>`_ (pdf) * `Reference Manual <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (pdf) * `Programming Manual <http://www.st.com/stonline/products/literature/pm/15491.pdf>`_ (assembly language and register reference) diff --git a/docs/source/libmaple-api.rst b/docs/source/libmaple-api.rst deleted file mode 100644 index d5b90b6..0000000 --- a/docs/source/libmaple-api.rst +++ /dev/null @@ -1,11 +0,0 @@ -.. _libmaple_api: - -======================== - libmaple API reference -======================== - -This page documents the lower-level features of libmaple, which may be -of use to programmers who don't wish to use the Arduino-style -environment provided by the `Maple IDE <maple-ide-install>`_. - -Stub. diff --git a/docs/source/libmaple.rst b/docs/source/libmaple.rst index a018cd7..b76c7c8 100644 --- a/docs/source/libmaple.rst +++ b/docs/source/libmaple.rst @@ -2,19 +2,19 @@ .. _libmaple: -==================== - libmaple Reference -==================== +``libmaple`` Reference +====================== .. image:: /_static/img/libmaple-screenshot-small.png :align: center :alt: libmaple screenshot -`LeafLabs libmaple <libmaple-libmaple>`_ is the low level library we have developed for for the ARM -Cortex-M3 chips manufactured by STMicroelectronics used in the Maple -boards (the `STM32F103x`_ series). We found the generic peripheral -libraries too painful to build on top of, and reimplemented the -functionality we needed in a simpler (and less general) form. +`LeafLabs libmaple <libmaple-libmaple>`_ is the low level library we +have developed for for the ARM Cortex-M3 chips manufactured by +STMicroelectronics used in the Maple boards (the `STM32F103x`_ +series). We found the generic peripheral libraries too painful to +build on top of, and reimplemented the functionality we needed in a +simpler (and less general) form. .. _libmaple-libmaple: http://github.com/leaflabs/libmaple .. _STM32F103x: http://www.st.com/stonline/stappl/productcatalog/app?path=/pages/stcom/PcStComPartNumberSearch.searchPartNumber&search=stm32f103 @@ -22,7 +22,7 @@ functionality we needed in a simpler (and less general) form. This library is transparently included in the `Maple IDE <http://leaflabs.com/docs/maple-ide/>`_, but we develop it separately using good old Unix command line tools and release it for advanced -users who might chafe at the “sketch” programming model of the +users who might chafe at the "sketch" programming model of the IDE. Included are some examples, a Makefile, and the compatibility wrappers and code to imitate the Arduino programming library. @@ -36,4 +36,7 @@ wrappers and code to imitate the Arduino programming library. :maxdepth: 2 Unix Toolchain Quickstart <unix-toolchain> - libmaple API reference <libmaple-api> + Guide to using GCC's ARM target <arm-gcc> + +.. TODO LATER create, style, and host a pure Doxygen libmaple +.. reference docs. This implies determining a stable API. diff --git a/docs/source/libraries.rst b/docs/source/libraries.rst index 6a97b0e..7623963 100644 --- a/docs/source/libraries.rst +++ b/docs/source/libraries.rst @@ -7,6 +7,9 @@ Maple Library Reference ========================= +.. Note: if you port an Arduino library and document it here, be sure +.. to update compatibility.rst to reflect that fact. + This page briefly summarizes the Arduino libraries that have been ported to Maple. You can use a library from within a sketch by going to Sketch > Import Library... from within the IDE, then choosing the @@ -18,13 +21,69 @@ in the description of the library. .. contents:: Contents :local: -.. _liquid_crystal: +.. toctree:: + :hidden: + + libs/servo.rst + +.. _libraries-servo: + +Servo +----- + +The Servo library is provided for convenient control of RC +servomotors. For more information, see the :ref:`Servo <libs-servo>` +reference. + +**Compatibility Note** + +The Servo class provides a public interface identical to the Arduino +version's documented functionality (as of Arduino 0021), so in most +cases, this library will be a drop-in replacement. + +However, there are some differences, essentially at the level of +implementation details. + +The major difference is that while the Arduino implementation drives +the servos with "bit-banged" :ref:`PWM <pwm>`, the Maple +implementation uses :ref:`timers <timers>` to drive the PWM directly. + +Consequently, **the Maple implementation only allows Servo instances +to** :ref:`attach <libs-servo-attach>` **to pins that support PWM**. + +To determine if a pin supports PWM (15 Maple pins do), you can either +check if "PWM" appears next to its number on the Maple silkscreen, or +consult the :ref:`pwmWrite() <lang-pwmwrite>` documentation. + +RC Servos expect a pulse approximately every 20ms. In the Maple +implementation, :ref:`periods <lang-hardwaretimer-setperiod>` are set +for entire timers, rather than individual channels. Thus, +``attach()``\ ing a Servo to a pin can interfere with other pins +associated with the same timer\ [#fard-servo]_. + +Because of this, we recommend connecting multiple servomotors to pins +which share a timer, in order to keep as many timers free for other +purposes as possible. Consult the :ref:`table provided in the timers +reference <timers-pin-channel-map>` to match up pins and timer +channels. + +Another difference: although it is not publicly documented to do so, +the Arduino implementation of `attach() +<http://arduino.cc/en/Reference/ServoAttach>`_ returns the timer +channel associated with the newly-attached pin, or 0 on failure (as of +Arduino 0021). The Maple implementation returns true on success, and +false on failure (and this is its documented behavior). + +.. _libraries-liquid-crystal: LiquidCrystal ------------- +.. TODO 0.0.10 make our own LiquidCrystal docs + The LiquidCrystal library allows Maple to control LCD screens. For -more information, see the Arduino LiquidCrystal documentation. +more information, see the `Arduino LiquidCrystal documentation +<http://www.arduino.cc/en/Reference/LiquidCrystal>`_. **Compatibility Note** @@ -32,7 +91,7 @@ At this time, no incompatibilities between the Maple and Arduino versions are known. Any observed differences should be considered bugs, and reported on the forums. -.. _wire: +.. _libraries-wire: Wire ---- @@ -54,8 +113,10 @@ the hardware i2c peripheral on the stm32 as well as the DMA for performance. Support for slave, smBUS, and multimaster modes are also slated for inclusion in the enhanced Wire port. -Function Reference -^^^^^^^^^^^^^^^^^^ +.. TODO 0.0.10 Wire docs in the cpp domain in own page under /libs/ + +Wire Function Reference +^^^^^^^^^^^^^^^^^^^^^^^ ``Wire.begin()`` Joins the i2c bus as master, using pin 20 as SDA and pin 21 as SCL @@ -124,3 +185,10 @@ Function Reference Returns the number of bytes which are still available for reading (with ``Wire.receive()``) from the last call to ``Wire.requestFrom(uint8, int)``. + +.. rubric:: Footnotes + +.. [#fard-servo] The Arduino implementation also captures timer + channels in groups as more Servo objects are attached, but the + details of which channels have their periods reset when are + slightly different. diff --git a/docs/source/libs/servo.rst b/docs/source/libs/servo.rst new file mode 100644 index 0000000..f92fd91 --- /dev/null +++ b/docs/source/libs/servo.rst @@ -0,0 +1,108 @@ +.. highlight:: cpp + +.. _libs-servo: + +======= + Servo +======= + +This documents the Servo library for controlling RC servomotors. It +is implemented as a thin layer over the built-in :ref:`timer +peripherals <timers>`. + +You can use this library in the :ref:`IDE <ide>` by choosing the Servo +item under the Sketch > Import Library... menu. + +If you are using the :ref:`Unix toolchain <unix-toolchain>`, the +library is located in ``$LIB_MAPLE_HOME/libraries/Servo/``. + +Servo Class Reference +--------------------- + +You can construct a Servo object by including the declaration :: + + Servo servo; + +in your sketch. This will create a Servo object called ``servo``. +You can then use any of its methods; for instance, to control a +servomotor attached to pin 9, you could write :: + + servo.attach(9); + +.. cpp:class:: Servo + + Class for controlling RC servomotors via :ref:`timers <timers>`. + +.. _libs-servo-attach: + +.. cpp:function:: bool Servo::attach(uint8 pin, uint16 min, uint16 max) + + Attach this Servo object to the given ``pin``. The pin must be + capable of PWM. You can check this by seeing if "PWM" is written + next to its number on the Maple silkscreen, or by consulting the + :ref:`pwmWrite() <lang-pwmwrite>` documentation. + + Sets this pin's :ref:`mode <lang-pinmode>` to :ref:`PWM + <lang-pinmode-wiringpinmode>`, and returns true if successful. + Does nothing and returns false if the pin doesn't support PWM. + + Parameter ``min`` is the pulse width corresponding to 0 degrees; + ``max`` is the pulse width corresponding to 180 degrees (both are + in microseconds). + +.. cpp:function:: bool Servo::attach(uint8 pin) + + Equivalent to :ref:`attach(pin, 544, 2400) <libs-servo-attach>`. + +.. _libs-servo-attached: + +.. cpp:function:: int Servo::attached() const + + If currently attached (via :ref:`attach() <libs-servo-attach>`) to + a pin, returns that pin's number. Returns ``NOT_ATTACHED`` + otherwise. + +.. cpp:function:: bool Servo::detach() + + If this Servo object is currently attached to pin, stops driving + the servo by setting a zero pulse width (this is accomplished by + setting the associated :ref:`channel mode + <lang-hardwaretimer-setchannelmode>` to ``TIMER_DISABLED``). + + Subsequently, calling :ref:`attached() <libs-servo-attached>` will + return ``NOT_ATTACHED``. + +.. cpp:function:: void Servo::write(unsigned int value) + + If ``value`` is less than ``SERVO_MAX_WRITE_ANGLE`` (which, for + Arduino compatibility, is 200), it's interpreted as an angle in + degrees. Otherwise, it's treated as a pulse width in microseconds. + + Drives the servo to target the given angle, based on a linear + interpolation of the ``min`` and ``max`` pulse widths determined + when :ref:`attach() <libs-servo-attach>` was called. + + Be aware that some (especially lower-cost) servos have fairly + non-linear maps between pulse width and target angle. Make sure to + test your motor before relying on this method. + +.. cpp:function:: void Servo::writeMicroseconds(uint16 pulseWidth) + + Drives the servo using a ``pulseWidth``-microsecond pulse. + + If ``pulseWidth`` is outside of the [``min``, ``max``\ ] pulse + width range set during :ref:`attach() <libs-servo-attach>`, it will + be clamped to lie in this range. + +.. cpp:function:: int Servo::read() const + + Returns the servo's target angle, in degrees. This will be clamped + to lie between 0 (when the pulse width is at most ``min``) and 180 + (when the pulse width is at least ``max``). + +.. cpp:function:: uint16 Servo::readMicroseconds() const + + Returns the pulse width of the wave currently driving the servo, in + microseconds. This will be clamped to lie in the [``min``, + ``max``\ ] pulse width range set during :ref:`attach() + <libs-servo-attach>`. diff --git a/docs/source/maple-quickstart.rst b/docs/source/maple-quickstart.rst index 6d99a4a..ca902f3 100644 --- a/docs/source/maple-quickstart.rst +++ b/docs/source/maple-quickstart.rst @@ -66,6 +66,8 @@ bottom window, and then a confirmation message will appear: :align: center :alt: Code verified successfully. +.. _maple-quickstart-upload: + Upload that program! -------------------- @@ -127,7 +129,7 @@ OS X: :alt: Board type and serial port for the OS X Then press the "Upload" button to upload your program to the -Maple. +Maple. .. image:: /_static/img/upload-button.png :align: center diff --git a/docs/source/pwm.rst b/docs/source/pwm.rst index 178d103..1a8f4df 100644 --- a/docs/source/pwm.rst +++ b/docs/source/pwm.rst @@ -1,10 +1,9 @@ .. _pwm: -============================== - Pulse-Width Modulation (PWM) -============================== +PWM +=== -Pulse Width Modulation is a basic technique to create repeated square +Pulse Width Modulation (PWM) is a basic technique to create repeated square waves (digital high/low voltage transitions) of user defined length and duty cycle. It can be used as a way to encode an "analog" signal on a single digital (high/low) line using the time between transitions @@ -29,9 +28,9 @@ Note that unlike the Arduino, the Maple does not have PWM functionality on pin D10; all other pins are :ref:`compatible <compatibility>`. -The following table shows which :ref:`timer <timers>` generates which -PWM outputs. See the :ref:`pin mapping table <pin-mapping-mega-table>` -to track down exactly which timer *channel* corresponds to each pin. +The following table shows which timer can generate which PWM +outputs. See the :ref:`pin mapping table <pin-mapping-mega-table>` to +track down exactly which timer *channel* corresponds to each pin. .. _pwm-timer-table: @@ -42,7 +41,7 @@ to track down exactly which timer *channel* corresponds to each pin. Timer1 | D6,D7,D8 Timer2 | D0,D1,D2,D3 Timer3 | D11,D12,D27,D28 - Timer4 | D5,D9,D14,D24 + Timer4 | D5,D9,D14,D24 Background ---------- @@ -66,12 +65,13 @@ The Maple has 16-bit PWM resolution, which means that the counter and variables can be as large as 65535, as opposed to 255 with 8-bit resolution. With a 72MHz clock rate, a PWM output could have maximum period of about one millisecond; using a :ref:`prescaler -<pwm-prescaler>` (clock divider) in front of the counter can increase -this maximum period. Setting the :ref:`period <pwm-overflow>` to -something other than the maximum value gives further control over the -total length of the waveform. However, this effectively limits the -resolution with which the duty can be modified: the duty must be less -than or equal to the period. +<lang-hardwaretimer-setprescalefactor>` (clock divider) in front of +the counter can increase this maximum period. Setting the +:ref:`period <lang-hardwaretimer-setperiod>` to something other than +the maximum value gives further control over the total length of the +waveform. However, this effectively limits the resolution with which +the duty can be modified: the duty must be less than or equal to the +period. Here are some commonly used PWM configurations (note that servos are notoriously variable, especially the lower cost models): @@ -94,58 +94,13 @@ notoriously variable, especially the lower cost models): Function Reference ------------------ -``pinMode(pin_num, PWM)`` - - This command is usually called from `setup()`_ to tell the - microcontroller that pin_num should be configured to PWM - output. ``PWM`` implies regular driven OUTPUT; ``PWM_OPEN_DRAIN`` is - also available (see the list of :ref:`GPIO modes <gpio-modes>` for - more information). - -.. _pwm-pwmwrite: - -``pwmWrite(pin_num, value)`` - - This command sets the PWM duty. User code is expected to determine - and honor the maximum value (based on the configured period). As a - convenience, ``analogWrite`` is an alias for ``pwmWrite`` to ease - porting Arduino code, though period and duty will have to be - recalibrated (see :ref:`compatibility <compatibility>`). - -.. _pwm-overflow: - -``Timer1.setOverflow(overflow)`` - - This function sets the period ("reload" or "overflow") value for - an entire PWM timer bank. The value is 16bit (0 to 65535) and - determines the maximum value that can be written with - :ref:`pwmWrite() <pwm-pwmwrite>` corresponding to 100% duty - cycle. This also affects the PWM frequency: the higher reload is, - the lower the PWM frequency will be. - - The PWM output pin starts HIGH, then the timer begins counting up - from zero (with frequency equal to 72MHz/:ref:`prescaler - <pwm-prescaler>`) until it hits the duty value, at which point it - drops to LOW. The timer then continues counting up until it hits - the total period (set with this function), at which point the - cycle starts again. - -.. _pwm-prescaler: - -``Timer[1,2,3,4].setPrescaleFactor(prescale)`` - - Find the appropriate timer for a given PWM header using the table - :ref:`above <pwm-timer-table>`, then set the prescaler. A - prescaler is a clock divider. The timer will normally count with - frequency equal to the STM32's normal clock (72MHz); this - corresponds to setting ``prescale`` to 1 (which is the default). - - If a longer frequency is desired, use a larger ``prescale`` value. - For instance, an 8MHz frequency can be achieved by setting - ``prescale`` to 9, since 72MHz / 9 = 8MHz. - - This function is normally called once from, `setup()`_, but the - timer can be reconfigured with a new prescaler at any time. +- :ref:`lang-pinmode` +- :ref:`lang-pwmwrite` +- :ref:`Timer API<lang-hardwaretimer>` (especially :ref:`setOverflow() + <lang-hardwaretimer-setoverflow>`, :ref:`setPrescaleFactor() + <lang-hardwaretimer-setprescalefactor>`, and :ref:`setPeriod() + <lang-hardwaretimer-setperiod>`). +- :ref:`Timers reference <timers>`. Recommended Reading ------------------- @@ -159,6 +114,5 @@ Recommended Reading * `So You Want To Use PWM, Eh? <http://www.arcfn.com/2009/07/secrets-of-arduino-pwm.html>`_ at Non-Lexical Vocables * STMicro documentation for STM32F103RB microcontroller: - * `All <http://www.st.com/mcu/devicedocs-STM32F103RB-110.html>`_ * `Datasheet <http://www.st.com/stonline/products/literature/ds/13587.pdf>`_ (pdf) * `Reference Manual <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (pdf) diff --git a/docs/source/specs.rst b/docs/source/specs.rst new file mode 100644 index 0000000..4972a83 --- /dev/null +++ b/docs/source/specs.rst @@ -0,0 +1,29 @@ +.. _specs: + +.. _specs-Technical-Specifications: + +================================ +Maple's Technical Specifications +================================ + + * STM32 F103RB: a **32-bit** ARM Cortex M3 microprocessor + * Clock Speed: **72 MHz** + * Operating Voltage: 3.3V + * Input Voltage (recommended): 3.0V-12V + * 39 Digital I/O Pins (:ref:`GPIO <gpio>`) + * 16 Analog Input Pins + * 12-bit **ADC** resolution (:ref:`ADC <adc>`) + * 15 **PWM** pins at 16-bit resolution (:ref:`PWM <pwm>`) + * Dedicated **USB** port for programming and communications (:ref:`USB<usb>`) + * External **JTAG** interface (:ref:`USB <jtag>`) + * **128 Flash** and **20KB SRAM** + * 64 Channel nested vector interrupt handler (including external interrupt on GPIO’s) + * Integrated **SPI** (:ref:`SPI<spi>`) + * Integrated **I2C** (:ref:`I2C<i2c>`) + * 7 Channels of Direct Memory Access (DMA) + * 3 **USART** divices (:ref:`USART <usart>`) + * Four 4-channel Timers (:ref:`Timers <timers>`) + * Supplies up to 800mA @ 3.3v + * Support for low power and sleep modes (<500uA) + * Dimensions are 2.05″x2.1″ + diff --git a/docs/source/spi.rst b/docs/source/spi.rst index 4cfd7e7..ba43eef 100644 --- a/docs/source/spi.rst +++ b/docs/source/spi.rst @@ -4,54 +4,16 @@ SPI ===== -The Maple has two SPI ports. The first has NSS on D10, MOSI on D11, -MISO on D12, and SCK on D13. The second has NSS on D31, SCK on D32, -MISO on D33, and MOSI on D34. +The Serial Peripheral Interface Bus (SPI) is a serial data transfer +protocol useful for interacting with a wide variety of hardware +peripherals. -.. _spi-speeds: +The Maple has two SPI ports. The first has NSS on D10, MOSI on +D11, MISO on D12, and SCK on D13. The second has NSS on D31, SCK on +D32, MISO on D33, and MOSI on D34. -Each port can be configured at one of the following speeds: - -* ``SPI_18MHZ``: 18 MHz -* ``SPI_9MHZ``: 9 MHz -* ``SPI_4_5MHZ``: 4.5 MHz -* ``SPI_2_25MHZ``: 2.25 MHz -* ``SPI_1_125MHZ``: 1.124 MHz -* ``SPI_562_500KHZ``: 562.500 KHz -* ``SPI_281_250KHZ``: 281.250 KHz -* ``SPI_140_625KHZ``: 140.625 KHz - -.. contents:: Contents - :local: - -Function Reference ------------------- - -``HardwareSPI Spi(number);`` - - This declaration must be included at the start of any sketch or - program that uses the SPI interface. The argument number is either - 1 or 2 and specifies which port to use. - -``Spi.begin(freq, endianness, mode)`` - - ``begin`` is usually called in `setup()`_ to configure the - baudrate of the given SPI port and to set up the header pins - appropriately. ``freq`` is one of the set listed :ref:`above - <spi-speeds>`; ``endianness`` is either ``LSBFIRST`` or - ``MSBFIRST``; mode is one of 0, 1, 2, 3, and specifies which "SPI - Mode" is used (see specification docs linked below). - -``Spi.begin()`` - - A default ``begin`` with no arguments is provided for the lazy; it - is equivalent to ``Spi.begin(SPI_1_125MHZ, MSBFIRST, 0)``. - -``Spi.send(data, size)`` - - Writes data into the port buffer to be transmitted as soon as - possible. ``data`` should be an array of type ``byte*``; ``size`` - should be the number of elements in ``data``. +The public libmaple API for managing the SPI ports is the +:ref:`HardwareSpi <lang-hardwarespi>` class. Recommended Reading ------------------- @@ -63,7 +25,6 @@ Recommended Reading * `Hardcore SPI on Arduino <http://klk64.com/arduino-spi/>`_ by kik64 * STMicro documentation for STM32F103RB microcontroller: - * `All <http://www.st.com/mcu/devicedocs-STM32F103RB-110.html>`_ * `Datasheet <http://www.st.com/stonline/products/literature/ds/13587.pdf>`_ (pdf) * `Reference Manual <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (pdf) diff --git a/docs/source/timers.rst b/docs/source/timers.rst index e0e57cb..56dd686 100644 --- a/docs/source/timers.rst +++ b/docs/source/timers.rst @@ -2,42 +2,73 @@ .. _timers: -======== - Timers -======== +Timers +====== There are four general purpose timers in the Maple microcontroller that can be configured to generate periodic or delayed events with minimal work done by the microcontroller. For example, the :ref:`PWM -<pwm>` channels, once enabled, generate regular square-wave signals on -specific output pins that will continue even if the microcontroller is -busy crunching numbers or handling communications interrupts. By -attaching interrupt handlers to these channels (instead of just -changing the voltage on an external pin), more complex events like -printing to a serial port, updating a variable, or emitting a whale -mating call can be scheduled. You can even modify the configuration of -the timer itself at a regular interval; the possibilities are endless! - -The four timers each have four separate compare channels. Each timer -is a single 16-bit counter that can be configured with both a -prescaler and an overflow value. The prescaler acts as a divider of -the 72MHz system clock; without prescaling the counter would get up to -65536 (2 to the 16th power) and roll over more than a thousand times a -second; even with the full prescaler it rolls over about once a -minute. The overflow value is the maximum value the counter will go up -to. It defaults to the full 65535; smaller values will cause the -counter to reset to zero more frequently. +<pwm>` channels can generate regular square-wave signals on specific +output pins without consuming extra clock cycles. By attaching +interrupt handlers to these channels (instead of just changing the +voltage on an external pin), more complex events can be scheduled. + +.. contents:: Contents + :local: + +Introduction +------------ + +.. _timers-prescale: + +The four timers each have four separate compare channels. Each channel +has an associated 16-bit counter that can be configured with a 16-bit +prescaler and a 16-bit overflow value. The prescaler determines how +fast the counter changes, while the overflow value determines when it +gets reset. + +The prescaler acts as a divider of the 72MHz system clock. That is, +with a prescaler of 1, the channel's counter increments with a +frequency of 72MHz, rolling over (passing the maximum 16-bit unsigned +integer value of 65,535) more than a thousand times a second. With a +prescaler of 7200, it has a frequency of (72/7200) MHz = 10 KHz, +rolling over approximately every 6.55 seconds. + +The overflow value is the maximum value the counter will go up to. It +defaults to the full 65,535; smaller values will cause the counter to +reset to zero more frequently. + +Whenever a channel's counter reaches its overflow value, an "update +event" interrupt is generated. You can configure the Maple to notify +you when this takes place, by registering an interrupt handler, which +is a function that will be called when the update event occurs. + +libmaple Reference +------------------ +The libmaple API for interacting with timers is documented at the +:ref:`HardwareTimer reference <lang-hardwaretimer>`. Caveats ------- +.. _timers-pwm-conflicts: + **PWM Conflicts:** Because PWM functionality on a given pin depends on the configuration of the timer and channel, you must chose your channels carefully if you want to use both timer interrupts and PWM in -the same program. Refer to the full :ref:`pin mapping table -<pin-mapping-mega-table>` to match up timer channels and Maple header -pin numbers. +the same program. Refer to the following table to match up timer +channels and Maple header pin numbers: + +.. _timers-pin-channel-map: + +.. csv-table:: + :header: Timer, Ch. 1 pin, Ch. 2 pin, Ch. 3 pin, Ch. 4 pin + + ``Timer1``, 6, 7, 8, -- + ``Timer2``, 2, 3, 1, 0 + ``Timer3``, 12, 11, 27, 28 + ``Timer4``, 5, 9, 14, 24 **Overhead:** there is some overhead associated with function and interrupt calls (loading and unloading the stack, preparing state, @@ -50,7 +81,7 @@ configuration being the same. **Jitter:** other interrupts (USB, Serial, SysTick, or other timers) can and will get called before or during the timer - interrupt routines, causing pseudo-random delays and other + interrupt routines, causing pseudorandom delays and other frustrations. Disabling the USB port (by calling ``SerialUSB.end()``, or just @@ -58,7 +89,8 @@ configuration being the same. auto-reset and communications functionality. This will require that you put your Maple into :ref:`perpetual bootloader mode <troubleshooting-perpetual-bootloader>` before uploading a new - program to it. + program to it (or somehow causing your program to re-enable serial + over USB using :ref:`SerialUSB.begin() <lang-serialusb-begin>`). Disabling SysTick with ``systick_disable()`` helps as well. However, calling this function will break the ``micros()`` and @@ -72,33 +104,6 @@ a handler isn't going to block other interrupts from firing (e.g. USB, Serial, SysTick) if those other interrupts are important for your program. -.. _timers-modes: - -General Timer Modes -------------------- - -``TIMER_DISABLED`` - - Exactly what it sounds like: the timer stops counting, interrupts - are not called, and no state changes are output. - -``TIMER_PWM`` - - This is the default mode for pins after initialization. See the - :ref:`PWM docs <pwm>` for more information on this mode. - - .. note:: - - ``Timer1.setChannel1Mode(TIMER_PWM)`` may not work as expected; - if you want PWM functionality on a channel, make sure you don't - set it to something else. - -``TIMER_OUTPUTCOMPARE`` - - In this mode, the timer counts from 0 to the overflow value - repeatedly; every time the counter value reaches one of the - channel compare values, the corresponding interrupt is fired. - SysTick Peripheral ------------------ @@ -110,133 +115,22 @@ VGA code, where the timing jitters are transformed into visual jags in the image. The SysTick peripheral can be disabled by calling ``systick_disable()``, and re-enabled using ``systick_resume()``. -Function Reference ------------------- - -For all of these functions, ``Timer1`` can be replaced with -``Timer2``, ``Timer3``, or ``Timer4``; the channel numbers also range -from 1 to 4. - -``Timer1.pause()``/\ ``Timer1.resume()`` - - These functions start and stop the counter without affecting the - rest of the configuration. These functions can be used during the - setup period to prevent interrupts from firing before they are - completely configured. Note that there is some function call - overhead with these functions, so they are not a perfect way to - align multiple timers to the same count value. - -``Timer1.setOverflow(val)`` - - Sets the overflow (or "reload") value for the whole timer; when - the counter reaches this value it resets to zero. Defaults to - 65535 (the largest unsigned 16bit integer); setting it to anything - lower will cause interrupts to be called more frequently (see the - setPeriod function below for a shortcut). This number sets the - maximum value for the channel compare values. - -``Timer1.setPrescaleFactor(val)`` - - The prescaler acts as a clock divider to slow down the rate at - which the counter increments. For example, the system clock rate - is 72MHz, so the counter will reach 65535 in (13.89 nanoseconds) * - (65535 counts) = (910.22 microseconds), or about a thousand times - a second. If you set the prescaler to 1098, then the clock rate is - effectively 65.56KHz, and the counter will reach 65536 in (15.25 - microseconds) * (65536 counts) = (0.999 seconds), or just about - once a second. Use the :ref:`setPeriod <timers-set-period>` - function below if you are allergic to math! - -.. _timers-set-period: - -``Timer1.setPeriod(val)`` - - This tricky trick will configure the prescaler and overflow values - to generate a timer reload with a period as close to val - microseconds as possible. It returns the chosen overflow value, - which you can then use to set the channel compare values - appropriately: if you just want the interrupts to fire when the - clock rolls over and you don't care about the relative "phase", - you can always set the channel compare values to 1. - - Remember: a microsecond is 1/1,000,000th of a second, or 1/1,000 - of a millisecond. The prescaler itself is 16bit, so the longest - period that can be configured is 1/(72MHz) * (2^32) = (59.65 - seconds) or about a minute. You can get around this by creating an - interrupt that increments a 32-bit variable, by using the - ``millis()`` function, or by interfacing with an external - real-time-clock chip. - -``Timer1.setCount(val)``/\ ``Timer1.getCount()`` - - These functions let you mess with the counter's brains - directly. You can probably make it not work if you try! The timer - is 16bit, so ``val`` and the return value of ``getCount`` are - ``uint16``. - -``Timer1.setChannel1Mode(MODE)`` - - This sets the given channel (here 1) of the given timer (here 1) - to the given mode. See the :ref:`list above <timers-modes>` for - possible values; for interrupts you want ``TIMER_OUTPUTCOMPARE``. - -``Timer1.setCompare1(val)`` - - Sets the compare value for the given channel; when the counter - reaches this value the interrupt for this channel will fire if the - channel is in output compare mode and an interrupt is attached. - - By default this only changes the relative offsets between events - on a single timer ("phase"); they don't control the frequency with - which they occur. However, a common trick is to increment the - compare value manually in the interrupt handler so that the event - will fire again after the increment period. There can be a - different increment value for each channel, so this trick allows - events to be programmed at 4 different rates on a single timer! - Note that function call overhead means that the smallest increment - rate is a couple microseconds. - -``Timer1.attachCompare1Interrupt(function)``/\ ``Timer1.detachCompare1Interrupt()`` - - This is how to attach or disable an interrupt handlers to timer - channels; this what will get called when the counter reaches the - compare value set with ``setCompareN(val)``. ``function`` - (sometimes referred to as an ISR: "interrupt service routine") - should be of a type that does not accept or return any values - (C/C++ programmers: ``void (function*)(void)``). They are just - like any other function in your sketch/program and must be - initialized at the top of the file and defined below. - - ``function`` should try to do what it has to do as fast as - possible. Blinking the LED, some logic, PWM updates, and Serial - writes are fine; writing to SerialUSB or waiting for user input - can take a long time and other compare interrupts won't fire. Tip: - if you have a ``delay()`` in your ISR, you're probably doing it - wrong. - - Stay vigilant here... function pointers are serious business, and - once you go down that path you'll find yourself in a `forest of - parentheses <http://mitpress.mit.edu/sicp/>`_ before you know it. - Code Examples ------------- LED blink ^^^^^^^^^ -\ :: +:: - #define LED_PIN 13 #define LED_RATE 500000 // in microseconds; should give 0.5Hz toggles void handler_led(void); - int toggle = 0; - void setup() { - // Set up the LED to blink - pinMode(LED_PIN, OUTPUT); + // Set up the LED to blink + pinMode(BOARD_LED_PIN, OUTPUT); // Setup Timer Timer2.setChannel1Mode(TIMER_OUTPUTCOMPARE); @@ -246,20 +140,17 @@ LED blink } void loop() { - // Nothing! It's all in the interrupts + // Nothing! It's all in the interrupts } void handler_led(void) { - toggle ^= 1; - digitalWrite(LED_PIN, toggle); - } + toggleLED(); + } Racing Counters ^^^^^^^^^^^^^^^ -\ :: - - #define BUTTON_PIN 38 +:: void handler_count1(void); void handler_count2(void); @@ -270,7 +161,7 @@ Racing Counters void setup() { // Set up BUT for input - pinMode(BUTTON_PIN, INPUT_PULLUP); + pinMode(BOARD_BUTTON_PIN, INPUT_PULLUP); // Setup Counting Timers Timer3.setChannel1Mode(TIMER_OUTPUTCOMPARE); @@ -282,7 +173,7 @@ Racing Counters Timer3.setOverflow(30000); Timer4.setOverflow(30000); Timer3.setCompare1(1000); // somewhere in the middle - Timer4.setCompare1(1000); + Timer4.setCompare1(1000); Timer3.attachCompare1Interrupt(handler1); Timer4.attachCompare1Interrupt(handler2); Timer3.resume(); @@ -291,14 +182,14 @@ Racing Counters void loop() { // Display the running counts - SerialUSB.print("Count 1: "); + SerialUSB.print("Count 1: "); SerialUSB.print(count1); - SerialUSB.print("\t\tCount 2: "); + SerialUSB.print("\t\tCount 2: "); SerialUSB.println(count2); // Run... while BUT is held, pause Count2 for(int i = 0; i<1000; i++) { - if(digitalRead(BUTTON_PIN)) { + if(digitalRead(BOARD_BUTTON_PIN)) { Timer4.pause(); } else { Timer4.resume(); @@ -309,7 +200,7 @@ Racing Counters void handler1(void) { count1++; - } + } void handler2(void) { count2++; - } + } diff --git a/docs/source/troubleshooting.rst b/docs/source/troubleshooting.rst index 9d452d1..f3052d9 100644 --- a/docs/source/troubleshooting.rst +++ b/docs/source/troubleshooting.rst @@ -30,10 +30,8 @@ use :ref:`perpetual bootloader mode My board is bricked! I can't upload via the bootloader no matter what! ---------------------------------------------------------------------- -Use the hardcoded serial STM32 serial bootloader to re-flash the -bootloader. - -.. TODO insert docs on reflashing the bootloader +Use the hardcoded serial STM32 serial bootloader to :ref:`re-flash the +bootloader <bootloader-reflashing>`. If it really is bricked, and you think it's our fault, `contact us <http://leaflabs.com/contact>`_\ ! @@ -43,8 +41,8 @@ My 5v peripheral doesn't work! (I2C, SPI, USART, etc) Yup, the Maple is a 3.3v board. You may need to use a level converter. See the :ref:`compatibility <compatibility>`, :ref:`GPIO -<gpio>`, or other :ref:`hardware specific documentation <hardware>` -for more information. +<gpio>`, or other :ref:`hardware specific documentation +<index-hardware>` for more information. The reset and D38/serial buttons don't seem to work reliably! ------------------------------------------------------------- @@ -100,18 +98,18 @@ a board selected. The work-around is to restart the IDE. Mysterious! ``NullPointerException`` ------------------------ -A classic! Make sure you have selected a board from the pulldown menu. +A classic! Make sure you have selected a board from the pulldown menu. .. TODO: remove when Python version is released ``undefined reference to setup()/loop()`` ----------------------------------------- -Your sketch/program either does not include one of the `setup -<setup()>`_ or `loop <loop()>`_ functions, or it was not found by the -compiler. Your program must include both ``void setup()`` and ``void -loop()`` functions; they don't have to do anything, but they **must** -be there. +Your sketch/program either does not include one of the :ref:`setup() +<lang-setup>` or `loop() <lang-loop>` functions, or it was not found +by the compiler. Your program must include both ``void setup()`` and +``void loop()`` functions; they don't have to do anything, but they +**must** be there. You can start with an example program (to see one in the IDE, click on File > Examples > Stubs > BareMinimum) to get the basic structure. @@ -152,7 +150,11 @@ is several times more FLASH memory available for user programs. ``No DFU capable USB device found`` ----------------------------------- -This probably means you don't have a Maple plugged in or powered on! +This probably means you don't have a Maple plugged in or powered on. +Try unplugging and plugging your Maple or pressing the RESET button. + +This can also happen if you disable the USB peripheral, e.g. using +:ref:`SerialUSB.end() <lang-serialusb-end>`. I have multiple Maples installed; how do I know which one will get flashed? --------------------------------------------------------------------------- @@ -163,19 +165,26 @@ board. There's no solution to this problem for now: you'll have to just plug in the Maples one at a time. If this is a real problem let us know and we'll see if we can come up with a better solution. +My flash programs don't seem to stick; they behave like they are RAM! +--------------------------------------------------------------------- + +If you have uploaded a program to RAM, this will take priority over +any program subsequently uploaded to flash. We'll be removing this +bug in a later version of the bootloader. For now, you can fix this +by unplugging your Maple to clear the contents of RAM, then plugging +it back in. + +If you are using the :ref:`Unix toolchain <unix-toolchain>`, Make sure +you :command:`make clean` when switching between FLASH and RAM +targets; :command:`make` isn't smart enough to rebuild everything that +needs to be for the new target. + .. _troubleshooting-shell: ===================== Command-line issues ===================== -My flash programs don't seem to stick; they behave like they are RAM! ---------------------------------------------------------------------- - -Make sure you :command:`make clean` when switching between FLASH and -RAM targets; :command:`make` isn't smart enough to rebuild everything -that needs to be for the new target. - [Linux] ``cdc_acm 3-1:1.0: no more free acm devices`` ----------------------------------------------------- diff --git a/docs/source/unix-toolchain.rst b/docs/source/unix-toolchain.rst index b595f70..e6039a2 100644 --- a/docs/source/unix-toolchain.rst +++ b/docs/source/unix-toolchain.rst @@ -32,20 +32,16 @@ GCC compiler tools <http://www.codesourcery.com/sgpp/features.html>`_ please post in the forums, so we can fold your tips into this document! -* :ref:`Linux setup <toolchain-linux-setup>` -* :ref:`OS X setup <toolchain-osx-setup>` -* :ref:`Test compilation <toolchain-test>` -* :ref:`Upload a program <toolchain-upload>` -* :ref:`Communicate over USB-serial interface <toolchain-serialusb>` -* :ref:`Starting your own projects <toolchain-projects>` -* :ref:`Debug with OpenOCD <toolchain-openocd>` -* :ref:`Do it all with Code::Blocks <toolchain-codeblocks>` -* :ref:`Go forth exuberantly! <toolchain-exuberantly>` +.. contents:: Contents + :local: .. _toolchain-linux-setup: -Linux Setup ------------ +Setup +----- + +Linux +^^^^^ These instructions are oriented towards Linux users using a contemporary Debian-based distribution. @@ -55,7 +51,7 @@ contemporary Debian-based distribution. First I'll give the commands to run, then explain:: $ sudo aptitude install build-essential git-core wget screen dfu-util \ - openocd python python-serial + openocd python python-serial You'll want to install a bunch of developer "basics" like :command:`make`, :command:`tar`, etc. A good catch-all for these @@ -90,23 +86,23 @@ package; this could also be installed with `easy_install **2. Fetch libmaple and Compiler Toolchain** :: - $ cd ~ - $ git clone git://github.com/leaflabs/libmaple.git libmaple - $ cd libmaple + $ cd ~ + $ git clone git://github.com/leaflabs/libmaple.git libmaple + $ cd libmaple $ wget http://static.leaflabs.com/pub/codesourcery/gcc-arm-none-eabi-latest-linux32.tar.gz $ tar xvf arm-*-linux32.tar.gz - $ export PATH=$PATH:~/libmaple/arm/bin # or wherever these tools ended up + $ export PATH=$PATH:~/libmaple/arm/bin # or wherever these tools ended up This step is fairly straightforward: do a git clone of the `libmaple repository <http://github.com/leaflabs/libmaple>`_ to some directory, then download and extract the ARM compiler toolchain. -The :file:`arm/bin/` directory will need to be added to -:envvar:`PATH`; you can check that this worked by entering -``arm-none-`` and hitting tab to auto-complete (bash should show a -bunch of results). Regardless of where you put the toolchain, make -sure to preserve its internal directory layout, as the binaries make -relative path calls and references. +The :file:`arm/bin/` directory will need to be added to ``PATH``; you +can check that this worked by entering ``arm-none-`` and hitting tab +to auto-complete (bash should show a bunch of results). Regardless of +where you put the toolchain, make sure to preserve its internal +directory layout, as the binaries make relative path calls and +references. .. _toolchain-udev: @@ -114,9 +110,9 @@ relative path calls and references. From the libmaple directory, :: - $ groups # make sure it includes plugdev; if not add, yourself to it - $ sudo cp support/scripts/45-maple.rules /etc/udev/rules.d/45-maple.rules - $ sudo /etc/init.d/udev restart + $ groups # make sure it includes plugdev; if not add, yourself to it + $ sudo cp support/scripts/45-maple.rules /etc/udev/rules.d/45-maple.rules + $ sudo /etc/init.d/udev restart As a security precaution on linux, unknown USB devices can only be accessed by the superuser. This udev script identifies the Maple based @@ -132,8 +128,8 @@ Great! Test your setup by :ref:`compiling a sample program .. _toolchain-osx-setup: -OS X Setup ----------- +OS X +^^^^ These instructions have been tested successfully on OS X 10.6.4. As stated previously, this document assumes a general level of Unix @@ -180,12 +176,12 @@ You will need the following tools to get started: :file:`/Applications/OpenMoko Flasher.app/Contents/Mac OS/dfu-util` To get access to it from the command line, just make a symbolic link - to the binary from some place on your :envvar:`PATH`:: + to the binary from some place on your ``PATH``:: $ ln -s /Applications/OpenMoko\ Flasher.app/Contents/Mac\ OS/dfu-util \ /somewhere/on/your/PATH/dfu-util - .. note:: + .. note:: Just copying the binary somewhere doesn't work, as it relies on dynamically linked libraries found elsewhere in the .app bundle. It's possible to pull just the relevant pieces out of the @@ -245,7 +241,7 @@ live with :: $ export PATH=$PATH:~/libmaple/arm/bin After that's done, you'll probably want to update your shell startup -script so :file:`~/libmaple/arm/bin` stays in your :envvar:`PATH`. +script so :file:`~/libmaple/arm/bin` stays in your ``PATH``. **So far, so good?** @@ -354,8 +350,8 @@ Starting your own projects -------------------------- So everything worked, and you want to start your own project? Great! -It's easy. Just set the environment variable :envvar:`LIB_MAPLE_HOME` -in your shell startup script to point to the libmaple repository you +It's easy. Just set the environment variable ``LIB_MAPLE_HOME`` in +your shell startup script to point to the libmaple repository you cloned (this tutorial assumes you put it in :file:`~/libmaple`). For example, if you use bash as your shell, just put this line in your :file:`~/.bashrc` or :file:`~/.bash_profile`:: @@ -421,12 +417,11 @@ but it might be helpful for people who are allergic to `vim <http://www.gnu.org/software/emacs/>`_. The simple configuration described here just calls down to the :file:`Makefile`, so follow the above directions to get the command line tools configured (you'll -definitely need the arm-none-eabi-* tools on your :envvar:`PATH`), -then `install Code::Blocks -<http://www.codeblocks.org/downloads/26>`_. You can do this on Linux -with:: +definitely need the arm-none-eabi-* tools on your ``PATH``), then +`install Code::Blocks <http://www.codeblocks.org/downloads/26>`_. You +can do this on Linux with:: - $ sudo aptitude install codeblocks + $ sudo aptitude install codeblocks The first time it runs you'll maybe want to disable all the glitzy "Getting Started" crap (when will they learn?). We've added a .cbp @@ -438,8 +433,8 @@ to get a feel for how it all works. To create your own "libmaple" project, start with an "Empty Project" with the "Folder to create project in" set to your -:envvar:`LIB_MAPLE_HOME`. Make sure that the "Resulting filename" is -in the top level directory as well. +``LIB_MAPLE_HOME``. Make sure that the "Resulting filename" is in the +top level directory as well. .. image:: /_static/img/codeblocks_newproject.png :align: center diff --git a/docs/source/usart.rst b/docs/source/usart.rst index 19b054f..3beb3fc 100644 --- a/docs/source/usart.rst +++ b/docs/source/usart.rst @@ -10,82 +10,18 @@ Hardware/Circuit Design ----------------------- -The Maple has 3 separate USART devices: ``Serial1``, ``Serial2``, and -``Serial3``. In the most simple use case, the RX and TX pins are used -to send data at a predetermined baudrate with the line voltage level -relative to ground. - -+-----------+--------+-----+ -|Port |Function|Pin | -+===========+========+=====+ -|``Serial1``|TX |D7 | -| | | | -| |RX |D8 | -| | | | -| |CK |D6 | -+-----------+--------+-----+ -|``Serial2``|TX |D1 | -| | | | -| |RX |D0 | -| | | | -| |CK |D10 | -| | | | -| |CTS |D2 | -| | | | -| |RTS |D3 | -+-----------+--------+-----+ -|``Serial3``|TX |D29 | -| | | | -| |RX |D30 | -| | | | -| |CK |D31 | -| | | | -| |CTS |D32 | -| | | | -| |RTS |D33 | -+-----------+--------+-----+ - -.. TODO make above less ugly +The Maple has 3 separate USART devices. In the most simple use case, +the RX and TX pins are used to send data at a predetermined baudrate +with the line voltage level relative to ground. Their usage is +documented in the :ref:`Serial Ports <lang-serial>` language reference +page. Compatible Devices and Specifications ------------------------------------- -We have successfully used the Maple USART ports with an FT232R-based USB-serial converter at up to 115200 baud; higher speeds should certainly be possible. - -Function Reference ------------------- - -In the following, you may replace ``SerialN`` with ``Serial1``, -``Serial2``, or ``Serial3``. - -``SerialN.begin(baudrate)`` - - ``SerialN.begin`` is usually called in `setup()`_ to configure the - baudrate of the given serial port and to set up the header pins - appropriately. It can be called at any time to reconfigure a port - or to change the baudrate. 9600 baud is the generic speed most - widely supported by other devices and terminals. - -``SerialN.print(...)``/\ ``SerialN.println(...)`` - - Writes data into the port buffer to be transmitted as soon as - possible. Accepts strings (``char*``). If a raw integer is - passed, the corresponding ASCII character will be transmitted; to - print out a number in human readable form add a second parameter - with the base system. - - For example, to print out the decimal number '1234' use - ``SerialN.print(1234, DEC)``; to print out the binary number - '1001', use ``SerialN.print(9, BIN)``. - -``SerialN.available()``/\ ``SerialN.read()`` - - ``SerialN.read()`` will return the next unread character that has - been received over the port. ``SerialN.available()`` returns how - many such bytes are available (or zero if none are). If none are - available, ``SerialN.read()`` will block/fail, so the usual - program structure is to poll with ``SerialN.available`` and only - read if a nonzero value is returned. +We have successfully used the Maple USART ports with an FT232R-based +USB-serial converter at up to 115200 baud; higher speeds should +certainly be possible. Recommended Reading ------------------- @@ -94,6 +30,5 @@ Recommended Reading * `Arduino reference on Serial <http://arduino.cc/en/Reference/Serial>`_ * STMicro documentation for STM32F103RB microcontroller: - * `All <http://www.st.com/mcu/devicedocs-STM32F103RB-110.html>`_ * `Datasheet <http://www.st.com/stonline/products/literature/ds/13587.pdf>`_ (pdf) * `Reference Manual <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (pdf) diff --git a/docs/source/usb.rst b/docs/source/usb.rst index baabde5..f502f31 100644 --- a/docs/source/usb.rst +++ b/docs/source/usb.rst @@ -6,21 +6,6 @@ USB ===== -.. note:: Changes and Caveats - - The SerialUSB functionality was modified for the 0.0.6 IDE - release. It now includes a 50 millisecond timeout for writes and - does not try to detect if the USB host is "really" connected or - just enumerated and initialized. This means that if you have a - number of SerialUSB writes or prints in your code and you are not - monitoring on a computer your program will run much, much slower - than if it is being monitored or totally disconnected (battery). - - You can avoid this behavior by :ref:`deciphering the port status - <usb-safe-print>` using the DTR and RTS line status; the behavior - of these control lines is platform dependent and we no longer - interpret them by default. - The Maple STM32 microprocessor includes a dedicated USB peripheral which can be configured to act as a general USB slave device with transfer rates up to 12Mbps (it unfortunately can't be configured as a @@ -30,152 +15,21 @@ and second, to emulate a regular serial port for use as a terminal (text read/write). The emulated terminal is relatively slow and inefficient; it is best -for transferring data at regular serial speeds (kilobaud). Users -requiring faster data transfer should consider implementing a -different communications protocol; the Maple could be reprogrammed to -appear as a mass storage device (thumb drive), human interface device -(mouse or keyboard), microphone, or any other USB device. +for transferring data at regular serial speeds (kilobaud). Library +support for accessing the emulated terminal is available at the +:ref:`SerialUSB <lang-serialusb>` reference. -The SerialUSB channel is also used as part of the auto-reset feature -of the IDE to program the board (on Maple Rev3): a :ref:`magic +The SerialUSB channel is used as part of the auto-reset feature of the +IDE to program the board on Maple Rev 3 and Rev 5: a :ref:`magic sequence of control line toggles and transmitted data <bootloader-rev3>` causes the Maple to reset itself and enter bootloader mode. As an unfortunate consequence, the auto-reset will not work if the IDE can not access the serial port, either due to a conflict with another program (serial monitor) or because the interface has been disabled from the Maple side (through -``SerialUSB.end()``). - -Function Reference ------------------- - -``SerialUSB.print(...)``/\ ``SerialUSB.println(...)`` - - Writes data into the port buffer to be transmitted as soon as - possible. Accepts strings (``char*``). If a raw integer is passed - the corresponding ASCII character will be transmitted; to print - out a number in human readable form add a second parameter with - the base system. For example, to print out the decimal number - "1234", use ``SerialUSB.print(1234, DEC)``; to print out the - binary number "1001", use ``SerialUSB.print(9, BIN)``. - -.. _usb-write: - -``SerialUSB.write(bytes)`` - - ``write`` is a lower-level function that writes bytes directly - into the buffer. :ref:`print() <usb-print>` often calls this - function dozens of times to write out a single formatted number; - user code can optimize raw data speed by calling this function - with 64-byte chunks instead. - -``SerialUSB.available()``/\ ``SerialUSB.read()`` - - ``SerialUSB.read()`` will return the next available character - (``byte``) that has been received over the port. - ``SerialUSB.available()`` returns how many such bytes are actually - available. If there is no data, ``read`` will block/fail, so the - usual program structure is to poll with ``available`` and only - ``read`` if there are data to read. - -``SerialUSB.read(buffer, length)`` - - An alternative version of ``SerialUSB.read``; will write the next - ``length`` available characters into the array ``buffer``. - -``SerialUSB.pending()`` - - Returns the number of bytes waiting in the transmit - buffer. Usercode can use this to prevent any blocking/waiting when - using the direct :ref:`write <usb-write>` functions, or to check - if data was actually requested/received by the host. - -``SerialUSB.getRTS()`` - - Returns the state (1 or 0) of the virtual RTS ("ready to send") - line. This can be used to guess if the USB host is actively - waiting for data (e.g., if a serial monitor program is running) or - just "configured" (i.e., the virtual serial port is configured, - but no program is reading data). - -``SerialUSB.getDTR()`` - - Returns the state (1 or 0) of the virtual DTR ("data terminal - ready") line. This can be used to guess if the USB host is - actively waiting for data (e.g., if a serial monitor program is - running) or just "configured" (i.e., the virtual serial port is - configured, but no program is reading data). - -.. TODO deprecate crap out of above two functions; write a sane API - -``SerialUSB.isConnected()`` - - Returns 1 if the USB host is connected and the virtual serial - interface is initialized (though not necessarily active). - Otherwise, returns 0. - -``SerialUSB.end()``/\ ``SerialUSB.begin()`` - - The USB peripheral is enabled by default so that the auto-reset - feature will work, but it can be disabled/restarted at any time - with the ``SerialUSB.end()`` and ``SerialUSB.begin()`` - functions. - - ``SerialUSB.end()`` is a relatively hard shutdown, similar to - unplugging the board; this may crash or confuse any programs - running host-side. Note that calling this function will require - the Maple to be put into :ref:`perpetual bootloader mode - <troubleshooting-perpetual-bootloader>` before another program can - be uploaded onto it, unless ``SerialUSB.begin()`` is called before - the upload is attempted. - - It's probably wise to wait a few seconds between calls to - ``SerialUSB.end()`` and ``SerialUSB.begin()`` (or to - ``SerialUSB.begin()`` and ``SerialUSB.print()``) to let the - computer reconfigure. - -Code Examples -------------- - -.. _usb-safe-print: - -Safe Print -^^^^^^^^^^ - -This function should run smoothly and not block; the LED should blink -at roughly the same speed whether being monitored, running from -battery, or connected but not monitored. You may need to experiment -with the DTR/RTS logic for your platform and device configuration. :: - - #define LED_PIN 13 - - void setup() { - /* Set up the LED to blink */ - pinMode(LED_PIN, OUTPUT); - } - - void loop() { - // LED will stay off if we are disconnected; - // will blink quickly if USB is unplugged (battery etc) - if(SerialUSB.isConnected()) { - digitalWrite(LED_PIN, 1); - } - delay(100); - - // If this logic fails to detect if bytes are going to - // be read by the USB host, then the println() will fully - // many times, causing a very slow LED blink. - // If the characters are printed and read, the blink will - // only slow a small amount when "really" connected, and fast - // when the virtual port is only configured. - if(SerialUSB.isConnected() && (SerialUSB.getDTR() || SerialUSB.getRTS())) { - for(int i=0; i<10; i++) { - SerialUSB.println(123456,BIN); - } - } - digitalWrite(LED_PIN, 0); - delay(100); - } +:ref:`SerialUSB.end() <lang-serialusb-end>`). A solution to the +second problem is the use of :ref:`perpetual bootloader mode +<troubleshooting-perpetual-bootloader>`. Recommended Reading ------------------- @@ -185,7 +39,6 @@ Recommended Reading * Linux Kernel documentation for `USB ACM <http://www.kernel.org/doc/Documentation/usb/acm.txt>`_ and `USB Serial <http://www.kernel.org/doc/Documentation/usb/usb-serial.txt>`_ * STMicro documentation for STM32F103RB microcontroller: - * `All documents <http://www.st.com/mcu/devicedocs-STM32F103RB-110.html>`_ * `Datasheet <http://www.st.com/stonline/products/literature/ds/13587.pdf>`_ (pdf) * `Reference Manual <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (pdf) * `Programming Manual <http://www.st.com/stonline/products/literature/pm/15491.pdf>`_ (pdf; assembly |
