diff options
| author | Marti Bolivar <mbolivar@mit.edu> | 2010-12-03 20:18:00 -0500 |
|---|---|---|
| committer | Marti Bolivar <mbolivar@mit.edu> | 2010-12-03 20:18:00 -0500 |
| commit | 5ceac644e90c929e77f05d357d1d35d45e673fac (patch) | |
| tree | 18c76f6117942fa46391fbbd8bd24e2c759c4895 /docs/source/lang | |
| parent | e5b1e44a8ae8c593456f4b4734f05c9065f6f07b (diff) | |
| download | librambutan-5ceac644e90c929e77f05d357d1d35d45e673fac.tar.gz librambutan-5ceac644e90c929e77f05d357d1d35d45e673fac.zip | |
cleaning up previous commits.
note that addition of new files under docs/source/lang/api and
docs/source/lang/cpp which were just copies of files in
docs/source/lang/ imply that change history is lost to git.
Diffstat (limited to 'docs/source/lang')
90 files changed, 0 insertions, 6714 deletions
diff --git a/docs/source/lang/abs.rst b/docs/source/lang/abs.rst deleted file mode 100644 index 0f71d9b..0000000 --- a/docs/source/lang/abs.rst +++ /dev/null @@ -1,48 +0,0 @@ -.. 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/analogread.rst b/docs/source/lang/analogread.rst deleted file mode 100644 index 0c93650..0000000 --- a/docs/source/lang/analogread.rst +++ /dev/null @@ -1,152 +0,0 @@ -.. highlight:: cpp - -.. _lang-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`\ ). - -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]_. - - -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. - -Finally, On the Arduino, it takes significantly longer to read analog -input: about 100 microseconds (0.0001 s), so the maximum reading rate -is 10,000 times a second. - - -See also --------- - -- :ref:`ADC note <adc>` -- `(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>`_. - - -.. include:: cc-attribution.txt diff --git a/docs/source/lang/analogwrite.rst b/docs/source/lang/analogwrite.rst deleted file mode 100644 index 2c50a42..0000000 --- a/docs/source/lang/analogwrite.rst +++ /dev/null @@ -1,166 +0,0 @@ -.. highlight:: cpp - -.. _lang-analogwrite: - -analogWrite() -============= - -.. note:: - - On the Maple, calling analogWrite() is the same as calling - :ref:`lang-pwmwrite`\ ; see that function's documentation for more - information. - - 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 (sigh) for the - sake of compatibility with Arduino, but we recommend using - :ref:`lang-pwmwrite` when writing new software, for clarity. - -.. 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, and 14, or twelve pins in total. That is at least as -*many* PWM pins as any Arduino board, but there are differences in -*which* pins support it. - -* 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. Maple supports PWM on pins 0, 1, and 14, - which the Mega does not, making the total number of pins supporting - PWM equal on these boards. - -* **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, 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 absolutely requires Arduino's PWM frequency (it -probably doesn't), then the steps are: - -1. Figure out which timer 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. One example is :ref:`interrupts <timers-attachinterrupt>`\ . -You've been :ref:`warned <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/lang/arithmetic.rst b/docs/source/lang/arithmetic.rst deleted file mode 100644 index 91fe22e..0000000 --- a/docs/source/lang/arithmetic.rst +++ /dev/null @@ -1,127 +0,0 @@ -.. 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/lang/array.rst b/docs/source/lang/array.rst deleted file mode 100644 index 30a818f..0000000 --- a/docs/source/lang/array.rst +++ /dev/null @@ -1,123 +0,0 @@ -.. highlight:: cpp - -.. _lang-array: - -Arrays -====== - -An array is a collection of variables that are accessed with an index -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 ------------------------------ - -All of the methods below are valid ways to create (declare) an -array. :: - - int myInts[6]; - int myPins[] = {2, 4, 8, 3, 6}; - int mySensVals[6] = {2, 4, -8, 3, 2}; - char message[6] = "hello"; - -You can declare an array without initializing it, as with myInts. In -the line referring to myPins, we declare an array without explicitly -choosing a size. The compiler counts the elements and creates an -array of the appropriate size. - -Finally, you can both initialize and size your array, as in -mySensVals. Note that when declaring an array with elements of type -char, one more element than your initialization is required, to hold -the required `null character <http://en.wikipedia.org/wiki/Null-terminated_string>`_. - - -Accessing an Array ------------------- - - -.. compound:: - - Arrays are **zero indexed**; that is, referring to the array - initialization above, the first element of the array is at index 0, - hence :: - - mySensVals[0] == 2; - mySensVals[1] == 4 - - and so forth. - -It also means that in an array with ten elements, index nine is the -last element. Hence:: - - int myArray[10]={9,3,2,4,3,2,7,8,9,11}; - // myArray[9] contains 11 - // myArray[10] is invalid and contains random information (other memory address) - -For this reason, you should be careful in accessing arrays. Accessing -past the end of an array (using an index number greater than your -declared array size - 1) is reading from memory that is in use for -other purposes. Reading from these locations is probably not going to -do much except yield invalid data. Writing to random memory locations -is definitely a bad idea, and can often lead to unhappy results such -as crashes or program malfunction. This can also be a difficult bug to -track down. - -Unlike Basic or Java, the C compiler does no checking to see if array -access is within legal bounds of the array size that you have -declared. - - -To assign a value to an array ------------------------------ - :: - - mySensVals[0] = 10; - - -To retrieve a value from an array ---------------------------------- - - :: - - x = mySensVals[4]; - - -Arrays and ``for`` Loops ------------------------- - -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:: - - int i; - for (i = 0; i < 5; i = i + 1) { - SerialUSB.println(myPins[i]); - } - - -Example -------- - -For a complete program that demonstrates the use of arrays, see the -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/lang/assignment.rst b/docs/source/lang/assignment.rst deleted file mode 100644 index b6ad4d5..0000000 --- a/docs/source/lang/assignment.rst +++ /dev/null @@ -1,70 +0,0 @@ -.. highlight:: cpp - -.. _lang-assignment: - -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 -operator tells the microcontroller to evaluate whatever value or -expression is on the right side of the equal sign, and store it in -the variable to the left of the equal sign [#fgross]_. - - - -Example -------- - -:: - - int sensVal; // declare an integer variable named sensVal - senVal = analogRead(0); // store the (digitized) input voltage at analog pin 0 in SensVal - - - -Programming Tips ----------------- - -The variable on the left side of the assignment operator ( = sign ) -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 --------- - - -- `if (comparison operators) <http://arduino.cc/en/Reference/If>`_ -- `char <http://arduino.cc/en/Reference/Char>`_ -- `int <http://arduino.cc/en/Reference/Int>`_ -- `long <http://arduino.cc/en/Reference/Long>`_ - - -.. rubric:: Footnotes - -.. [#fgross] Experienced C++ programmers know this to be an - oversimplification of what happens when the variable on the left - hand side is an object. See Richard Gillam's wonderful and scary - `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/attachinterrupt.rst b/docs/source/lang/attachinterrupt.rst deleted file mode 100644 index 0b8907f..0000000 --- a/docs/source/lang/attachinterrupt.rst +++ /dev/null @@ -1,102 +0,0 @@ -.. highlight:: cpp - -.. _lang-attachinterrupt: - -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 - -.. doxygenenum:: ExtIntTriggerMode - -.. doxygentypedef:: voidFuncPtr - -Discussion ----------- - -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. - -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 ----------------- - -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, -or monitoring user input. - - -If you wanted to insure that a program always caught the pulses -from a rotary encoder, never missing a pulse, it would make it very -tricky to write a program to do anything else, because the program -would need to constantly poll the sensor lines for the encoder, in -order to catch pulses when they occurred. Other sensors have a -similar interface dynamic too, such as trying to read a sound -sensor that is trying to catch a click, or an infrared slot sensor -(photo-interrupter) trying to catch a coin drop. In all of these -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; // must declare volatile, since it's - // modified within the blink handler - - void setup() { - pinMode(maple_led_pin, OUTPUT); - attachInterrupt(0, blink, CHANGE); - } - - void loop() { - digitalWrite(maple_led_pin, state); - } - - void blink() { - state = !state; - } - - -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). 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 --------- - - -- :ref:`detachInterrupt <lang-detachinterrupt>` -- :ref:`external-interrupts` - - - -.. include:: cc-attribution.txt diff --git a/docs/source/lang/bit.rst b/docs/source/lang/bit.rst deleted file mode 100644 index dd5c050..0000000 --- a/docs/source/lang/bit.rst +++ /dev/null @@ -1,44 +0,0 @@ -.. _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/bitclear.rst b/docs/source/lang/bitclear.rst deleted file mode 100644 index 941f912..0000000 --- a/docs/source/lang/bitclear.rst +++ /dev/null @@ -1,44 +0,0 @@ -.. _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/bitread.rst b/docs/source/lang/bitread.rst deleted file mode 100644 index 46b4478..0000000 --- a/docs/source/lang/bitread.rst +++ /dev/null @@ -1,46 +0,0 @@ -.. _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/bitset.rst b/docs/source/lang/bitset.rst deleted file mode 100644 index ccd76de..0000000 --- a/docs/source/lang/bitset.rst +++ /dev/null @@ -1,46 +0,0 @@ -.. _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/bitshift.rst b/docs/source/lang/bitshift.rst deleted file mode 100644 index e1c8de0..0000000 --- a/docs/source/lang/bitshift.rst +++ /dev/null @@ -1,144 +0,0 @@ -.. 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/bitwisemath.rst b/docs/source/lang/bitwisemath.rst deleted file mode 100644 index 28fe6bf..0000000 --- a/docs/source/lang/bitwisemath.rst +++ /dev/null @@ -1,186 +0,0 @@ -.. 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/bitwrite.rst b/docs/source/lang/bitwrite.rst deleted file mode 100644 index b3feff2..0000000 --- a/docs/source/lang/bitwrite.rst +++ /dev/null @@ -1,46 +0,0 @@ -.. 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/boolean.rst b/docs/source/lang/boolean.rst deleted file mode 100644 index 8d6aa5c..0000000 --- a/docs/source/lang/boolean.rst +++ /dev/null @@ -1,91 +0,0 @@ -.. 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/booleanvariables.rst b/docs/source/lang/booleanvariables.rst deleted file mode 100644 index 6051b8c..0000000 --- a/docs/source/lang/booleanvariables.rst +++ /dev/null @@ -1,54 +0,0 @@ -.. 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/break.rst b/docs/source/lang/break.rst deleted file mode 100644 index ce8ac17..0000000 --- a/docs/source/lang/break.rst +++ /dev/null @@ -1,35 +0,0 @@ -.. 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/byte.rst b/docs/source/lang/byte.rst deleted file mode 100644 index 45c9d5f..0000000 --- a/docs/source/lang/byte.rst +++ /dev/null @@ -1,34 +0,0 @@ -.. 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/bytecast.rst b/docs/source/lang/bytecast.rst deleted file mode 100644 index b3f0de2..0000000 --- a/docs/source/lang/bytecast.rst +++ /dev/null @@ -1,50 +0,0 @@ -.. 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/char.rst b/docs/source/lang/char.rst deleted file mode 100644 index b8747f3..0000000 --- a/docs/source/lang/char.rst +++ /dev/null @@ -1,50 +0,0 @@ -.. 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/charcast.rst b/docs/source/lang/charcast.rst deleted file mode 100644 index a480dec..0000000 --- a/docs/source/lang/charcast.rst +++ /dev/null @@ -1,36 +0,0 @@ -.. 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/comments.rst b/docs/source/lang/comments.rst deleted file mode 100644 index c5f118a..0000000 --- a/docs/source/lang/comments.rst +++ /dev/null @@ -1,67 +0,0 @@ -.. 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/comparison.rst b/docs/source/lang/comparison.rst deleted file mode 100644 index b24355f..0000000 --- a/docs/source/lang/comparison.rst +++ /dev/null @@ -1,87 +0,0 @@ -.. 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/compoundarithmetic.rst b/docs/source/lang/compoundarithmetic.rst deleted file mode 100644 index 420f1db..0000000 --- a/docs/source/lang/compoundarithmetic.rst +++ /dev/null @@ -1,44 +0,0 @@ -.. 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/compoundbitwise.rst b/docs/source/lang/compoundbitwise.rst deleted file mode 100644 index a4bbb24..0000000 --- a/docs/source/lang/compoundbitwise.rst +++ /dev/null @@ -1,231 +0,0 @@ -.. 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/const.rst b/docs/source/lang/const.rst deleted file mode 100644 index 52de85f..0000000 --- a/docs/source/lang/const.rst +++ /dev/null @@ -1,52 +0,0 @@ -.. 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/constants.rst b/docs/source/lang/constants.rst deleted file mode 100644 index bc5c894..0000000 --- a/docs/source/lang/constants.rst +++ /dev/null @@ -1,304 +0,0 @@ -.. _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`` - -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/constrain.rst b/docs/source/lang/constrain.rst deleted file mode 100644 index d19b61c..0000000 --- a/docs/source/lang/constrain.rst +++ /dev/null @@ -1,69 +0,0 @@ -.. 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/continue.rst b/docs/source/lang/continue.rst deleted file mode 100644 index 13d1815..0000000 --- a/docs/source/lang/continue.rst +++ /dev/null @@ -1,32 +0,0 @@ -.. 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/cos.rst b/docs/source/lang/cos.rst deleted file mode 100644 index 3fbb0af..0000000 --- a/docs/source/lang/cos.rst +++ /dev/null @@ -1,32 +0,0 @@ -.. _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/curly-braces.rst b/docs/source/lang/curly-braces.rst deleted file mode 100644 index a4bd3dc..0000000 --- a/docs/source/lang/curly-braces.rst +++ /dev/null @@ -1,109 +0,0 @@ -.. 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/define.rst b/docs/source/lang/define.rst deleted file mode 100644 index 677390d..0000000 --- a/docs/source/lang/define.rst +++ /dev/null @@ -1,56 +0,0 @@ -.. 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/delay.rst b/docs/source/lang/delay.rst deleted file mode 100644 index 90ca268..0000000 --- a/docs/source/lang/delay.rst +++ /dev/null @@ -1,72 +0,0 @@ -.. 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/delaymicroseconds.rst b/docs/source/lang/delaymicroseconds.rst deleted file mode 100644 index 24a8286..0000000 --- a/docs/source/lang/delaymicroseconds.rst +++ /dev/null @@ -1,65 +0,0 @@ -.. 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/detachinterrupt.rst b/docs/source/lang/detachinterrupt.rst deleted file mode 100644 index adb2439..0000000 --- a/docs/source/lang/detachinterrupt.rst +++ /dev/null @@ -1,37 +0,0 @@ -.. _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/digitalread.rst b/docs/source/lang/digitalread.rst deleted file mode 100644 index 3502587..0000000 --- a/docs/source/lang/digitalread.rst +++ /dev/null @@ -1,58 +0,0 @@ -.. 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/digitalwrite.rst b/docs/source/lang/digitalwrite.rst deleted file mode 100644 index 6124d5f..0000000 --- a/docs/source/lang/digitalwrite.rst +++ /dev/null @@ -1,68 +0,0 @@ -.. 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/double.rst b/docs/source/lang/double.rst deleted file mode 100644 index 1527778..0000000 --- a/docs/source/lang/double.rst +++ /dev/null @@ -1,48 +0,0 @@ -.. _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/doublecast.rst b/docs/source/lang/doublecast.rst deleted file mode 100644 index 511fe24..0000000 --- a/docs/source/lang/doublecast.rst +++ /dev/null @@ -1,27 +0,0 @@ -.. 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/dowhile.rst b/docs/source/lang/dowhile.rst deleted file mode 100644 index fe92226..0000000 --- a/docs/source/lang/dowhile.rst +++ /dev/null @@ -1,27 +0,0 @@ -.. 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/enum.rst b/docs/source/lang/enum.rst deleted file mode 100644 index ba82383..0000000 --- a/docs/source/lang/enum.rst +++ /dev/null @@ -1,53 +0,0 @@ -.. 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/float.rst b/docs/source/lang/float.rst deleted file mode 100644 index 6937c8c..0000000 --- a/docs/source/lang/float.rst +++ /dev/null @@ -1,50 +0,0 @@ -.. 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/floatcast.rst b/docs/source/lang/floatcast.rst deleted file mode 100644 index 4766478..0000000 --- a/docs/source/lang/floatcast.rst +++ /dev/null @@ -1,28 +0,0 @@ -.. 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/for.rst b/docs/source/lang/for.rst deleted file mode 100644 index 71c5aca..0000000 --- a/docs/source/lang/for.rst +++ /dev/null @@ -1,142 +0,0 @@ -.. 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/goto.rst b/docs/source/lang/goto.rst deleted file mode 100644 index ff2f248..0000000 --- a/docs/source/lang/goto.rst +++ /dev/null @@ -1,130 +0,0 @@ -.. 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/highbyte.rst b/docs/source/lang/highbyte.rst deleted file mode 100644 index 50a1fa6..0000000 --- a/docs/source/lang/highbyte.rst +++ /dev/null @@ -1,59 +0,0 @@ -.. 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/if.rst b/docs/source/lang/if.rst deleted file mode 100644 index bef89e2..0000000 --- a/docs/source/lang/if.rst +++ /dev/null @@ -1,121 +0,0 @@ -.. 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/include.rst b/docs/source/lang/include.rst deleted file mode 100644 index 74fe7af..0000000 --- a/docs/source/lang/include.rst +++ /dev/null @@ -1,72 +0,0 @@ -.. 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/increment.rst b/docs/source/lang/increment.rst deleted file mode 100644 index 6dffa80..0000000 --- a/docs/source/lang/increment.rst +++ /dev/null @@ -1,37 +0,0 @@ -.. 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/int.rst b/docs/source/lang/int.rst deleted file mode 100644 index ca75f75..0000000 --- a/docs/source/lang/int.rst +++ /dev/null @@ -1,64 +0,0 @@ -.. 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/intcast.rst b/docs/source/lang/intcast.rst deleted file mode 100644 index 386fe14..0000000 --- a/docs/source/lang/intcast.rst +++ /dev/null @@ -1,29 +0,0 @@ -.. 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/keywords.rst b/docs/source/lang/keywords.rst deleted file mode 100644 index e4ebe99..0000000 --- a/docs/source/lang/keywords.rst +++ /dev/null @@ -1,205 +0,0 @@ -.. _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-numeric-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/long.rst b/docs/source/lang/long.rst deleted file mode 100644 index d8498c0..0000000 --- a/docs/source/lang/long.rst +++ /dev/null @@ -1,52 +0,0 @@ -.. 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/longcast.rst b/docs/source/lang/longcast.rst deleted file mode 100644 index 2b92345..0000000 --- a/docs/source/lang/longcast.rst +++ /dev/null @@ -1,27 +0,0 @@ -.. 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/loop.rst b/docs/source/lang/loop.rst deleted file mode 100644 index d8f6183..0000000 --- a/docs/source/lang/loop.rst +++ /dev/null @@ -1,45 +0,0 @@ -.. 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/lowbyte.rst b/docs/source/lang/lowbyte.rst deleted file mode 100644 index 58e622f..0000000 --- a/docs/source/lang/lowbyte.rst +++ /dev/null @@ -1,25 +0,0 @@ -.. _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/map.rst b/docs/source/lang/map.rst deleted file mode 100644 index 79122b3..0000000 --- a/docs/source/lang/map.rst +++ /dev/null @@ -1,68 +0,0 @@ -.. 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/max.rst b/docs/source/lang/max.rst deleted file mode 100644 index d38eebe..0000000 --- a/docs/source/lang/max.rst +++ /dev/null @@ -1,65 +0,0 @@ -.. 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/micros.rst b/docs/source/lang/micros.rst deleted file mode 100644 index f12976b..0000000 --- a/docs/source/lang/micros.rst +++ /dev/null @@ -1,46 +0,0 @@ -.. 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/millis.rst b/docs/source/lang/millis.rst deleted file mode 100644 index 54e4507..0000000 --- a/docs/source/lang/millis.rst +++ /dev/null @@ -1,52 +0,0 @@ -.. 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/min.rst b/docs/source/lang/min.rst deleted file mode 100644 index 1245f6f..0000000 --- a/docs/source/lang/min.rst +++ /dev/null @@ -1,66 +0,0 @@ -.. 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/modulo.rst b/docs/source/lang/modulo.rst deleted file mode 100644 index 289fba0..0000000 --- a/docs/source/lang/modulo.rst +++ /dev/null @@ -1,70 +0,0 @@ -.. 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/numeric-types.rst b/docs/source/lang/numeric-types.rst deleted file mode 100644 index 9d2be48..0000000 --- a/docs/source/lang/numeric-types.rst +++ /dev/null @@ -1,79 +0,0 @@ -.. _lang-numeric-types: - -Numeric types -============= - -This document serves as a reference for all of the built-in numeric -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``; several are -defined in in `libmaple_types.h -<https://github.com/leaflabs/libmaple/blob/master/libmaple/libmaple_types.h>`_. - -.. _lang-numeric-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. diff --git a/docs/source/lang/pinmode.rst b/docs/source/lang/pinmode.rst deleted file mode 100644 index b9095da..0000000 --- a/docs/source/lang/pinmode.rst +++ /dev/null @@ -1,77 +0,0 @@ -.. highlight:: cpp - -.. _lang-pinmode: - -pinMode() -========= - -.. contents:: Contents - :local: - -Library Documentation ---------------------- - -.. doxygenfunction:: pinMode - -.. 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/pointer.rst b/docs/source/lang/pointer.rst deleted file mode 100644 index 0a42270..0000000 --- a/docs/source/lang/pointer.rst +++ /dev/null @@ -1,31 +0,0 @@ -.. _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/pow.rst b/docs/source/lang/pow.rst deleted file mode 100644 index 4280400..0000000 --- a/docs/source/lang/pow.rst +++ /dev/null @@ -1,23 +0,0 @@ -.. _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/pwmwrite.rst b/docs/source/lang/pwmwrite.rst deleted file mode 100644 index 7a1d51f..0000000 --- a/docs/source/lang/pwmwrite.rst +++ /dev/null @@ -1,49 +0,0 @@ -.. 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. - -.. contents:: Contents - :local: - -Library Documentation ---------------------- - -.. doxygenfunction:: pwmWrite - -Example -------- - -Sets the output to the LED proportional to the value read from the -potentiometer:: - - int ledPin = 13; // LED connected to pin 13 (Maple) - 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 LED pin as output - - pinMode(analogPin, PWM); // sets the potentiometer pin as PWM - // output - } - - void loop() { - val = analogRead(analogPin); // read the input pin - - analogWrite(ledPin, 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/random.rst b/docs/source/lang/random.rst deleted file mode 100644 index f2a9762..0000000 --- a/docs/source/lang/random.rst +++ /dev/null @@ -1,73 +0,0 @@ -.. 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/randomseed.rst b/docs/source/lang/randomseed.rst deleted file mode 100644 index d0a15b7..0000000 --- a/docs/source/lang/randomseed.rst +++ /dev/null @@ -1,60 +0,0 @@ -.. 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/return.rst b/docs/source/lang/return.rst deleted file mode 100644 index 7b5039e..0000000 --- a/docs/source/lang/return.rst +++ /dev/null @@ -1,61 +0,0 @@ -.. 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/scope.rst b/docs/source/lang/scope.rst deleted file mode 100644 index 7b65bab..0000000 --- a/docs/source/lang/scope.rst +++ /dev/null @@ -1,120 +0,0 @@ -.. 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/lang/semicolon.rst b/docs/source/lang/semicolon.rst deleted file mode 100644 index 8164616..0000000 --- a/docs/source/lang/semicolon.rst +++ /dev/null @@ -1,25 +0,0 @@ -.. highlight:: cpp - -.. _lang-semicolon: - -Semicolon (``;``) -================= - -Used to end a line of code. Example:: - - int a = 13; - -Tip ---- - -Forgetting to end a line in a semicolon will result in a compiler -error. The error text may be obvious, and refer to a missing -semicolon, or it may not. If an impenetrable or seemingly illogical -compiler error comes up, one of the first things to check is a -missing semicolon, in the immediate vicinity, preceding the line at -which the compiler complained. - - - - -.. include:: cc-attribution.txt diff --git a/docs/source/lang/serial.rst b/docs/source/lang/serial.rst deleted file mode 100644 index ca89b31..0000000 --- a/docs/source/lang/serial.rst +++ /dev/null @@ -1,226 +0,0 @@ -.. _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/serialusb.rst b/docs/source/lang/serialusb.rst deleted file mode 100644 index af3a7e0..0000000 --- a/docs/source/lang/serialusb.rst +++ /dev/null @@ -1,242 +0,0 @@ -.. 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 - instance. - -.. 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. - -.. 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::flush() - - Removes the contents of the Serial's associated input buffer. That - is, clears any buffered characters, so that the next character read - is guaranteed to be new. - -.. 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/setup.rst b/docs/source/lang/setup.rst deleted file mode 100644 index 837ddd6..0000000 --- a/docs/source/lang/setup.rst +++ /dev/null @@ -1,29 +0,0 @@ -.. 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/sin.rst b/docs/source/lang/sin.rst deleted file mode 100644 index 398b8f3..0000000 --- a/docs/source/lang/sin.rst +++ /dev/null @@ -1,32 +0,0 @@ -.. _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/sizeof.rst b/docs/source/lang/sizeof.rst deleted file mode 100644 index eae509c..0000000 --- a/docs/source/lang/sizeof.rst +++ /dev/null @@ -1,64 +0,0 @@ -.. 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/sq.rst b/docs/source/lang/sq.rst deleted file mode 100644 index bd32648..0000000 --- a/docs/source/lang/sq.rst +++ /dev/null @@ -1,46 +0,0 @@ -.. 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/sqrt.rst b/docs/source/lang/sqrt.rst deleted file mode 100644 index 956a754..0000000 --- a/docs/source/lang/sqrt.rst +++ /dev/null @@ -1,25 +0,0 @@ -.. _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/static.rst b/docs/source/lang/static.rst deleted file mode 100644 index 5d1802e..0000000 --- a/docs/source/lang/static.rst +++ /dev/null @@ -1,57 +0,0 @@ -.. 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/string.rst b/docs/source/lang/string.rst deleted file mode 100644 index 0a270da..0000000 --- a/docs/source/lang/string.rst +++ /dev/null @@ -1,128 +0,0 @@ -.. 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/switchcase.rst b/docs/source/lang/switchcase.rst deleted file mode 100644 index b484bc5..0000000 --- a/docs/source/lang/switchcase.rst +++ /dev/null @@ -1,118 +0,0 @@ -.. 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/tan.rst b/docs/source/lang/tan.rst deleted file mode 100644 index 4bbe0db..0000000 --- a/docs/source/lang/tan.rst +++ /dev/null @@ -1,31 +0,0 @@ -.. _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/unsignedchar.rst b/docs/source/lang/unsignedchar.rst deleted file mode 100644 index 5b946ed..0000000 --- a/docs/source/lang/unsignedchar.rst +++ /dev/null @@ -1,33 +0,0 @@ -.. 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/unsignedint.rst b/docs/source/lang/unsignedint.rst deleted file mode 100644 index f6311da..0000000 --- a/docs/source/lang/unsignedint.rst +++ /dev/null @@ -1,55 +0,0 @@ -.. 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/unsignedlong.rst b/docs/source/lang/unsignedlong.rst deleted file mode 100644 index 14a4fc3..0000000 --- a/docs/source/lang/unsignedlong.rst +++ /dev/null @@ -1,41 +0,0 @@ -.. 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/variables.rst b/docs/source/lang/variables.rst deleted file mode 100644 index 9094cd5..0000000 --- a/docs/source/lang/variables.rst +++ /dev/null @@ -1,170 +0,0 @@ -.. 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-numeric-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-numeric-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-numeric-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/void.rst b/docs/source/lang/void.rst deleted file mode 100644 index 88bd448..0000000 --- a/docs/source/lang/void.rst +++ /dev/null @@ -1,31 +0,0 @@ -.. highlight:: cpp - -.. _lang-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, 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/volatile.rst b/docs/source/lang/volatile.rst deleted file mode 100644 index 276bb6a..0000000 --- a/docs/source/lang/volatile.rst +++ /dev/null @@ -1,65 +0,0 @@ -.. 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/while.rst b/docs/source/lang/while.rst deleted file mode 100644 index 9047d05..0000000 --- a/docs/source/lang/while.rst +++ /dev/null @@ -1,38 +0,0 @@ -.. 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 |