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diff --git a/source/lang/serialusb.rst b/source/lang/serialusb.rst deleted file mode 100644 index af3a7e0..0000000 --- a/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); - } - |