tmk_core/tool/mbed/mbed-sdk/libraries/tests/libs/SerialHalfDuplex/SerialHalfDuplex.h

   1 /* mbed Microcontroller Library - SerialHalfDuplex
   2  * Copyright (c) 2010-2011 ARM Limited. All rights reserved.
   3  */
   4 #ifndef MBED_SERIALHALFDUPLEX_H
   5 #define MBED_SERIALHALFDUPLEX_H
   6
   7 #include "platform.h"
   8
   9 #if DEVICE_SERIAL
  10
  11 #include "Serial.h"
  12 #include "gpio_api.h"
  13
  14 namespace mbed {
  15
  16 /** A serial port (UART) for communication with other devices using
  17  * Half-Duplex, allowing transmit and receive on a single
  18  * shared transmit and receive line. Only one end should be transmitting
  19  * at a time.
  20  *
  21  * Both the tx and rx pin should be defined, and wired together.
  22  * This is in addition to them being wired to the other serial
  23  * device to allow both read and write functions to operate.
  24  *
  25  *  For Simplex and Full-Duplex Serial communication, see Serial()
  26  *
  27  *  Example:
  28  * @code
  29  * // Send a byte to a second HalfDuplex device, and read the response
  30  *
  31  * #include "mbed.h"
  32  *
  33  * // p9 and p10 should be wired together to form "a"
  34  * // p28 and p27 should be wired together to form "b"
  35  * // p9/p10 should be wired to p28/p27 as the Half Duplex connection
  36  *
  37  * SerialHalfDuplex a(p9, p10);
  38  * SerialHalfDuplex b(p28, p27);
  39  *
  40  * void b_rx() { // second device response
  41  *     b.putc(b.getc() + 4);
  42  * }
  43  *
  44  * int main() {
  45  *     b.attach(&b_rx);
  46  *     for (int c = 'A'; c < 'Z'; c++) {
  47  *         a.putc(c);
  48  *         printf("sent [%c]\n", c);
  49  *         wait(0.5);   // b should respond
  50  *         if (a.readable()) {
  51  *             printf("received [%c]\n", a.getc());
  52  *         }
  53  *     }
  54  * }
  55  * @endcode
  56  */
  57 class SerialHalfDuplex : public Serial {
  58
  59 public:
  60     /** Create a half-duplex serial port, connected to the specified transmit
  61      * and receive pins.
  62      *
  63      * These pins should be wired together, as well as to the target device
  64      *
  65      *  @param tx Transmit pin
  66      *  @param rx Receive pin
  67      */
  68     SerialHalfDuplex(PinName tx, PinName rx);
  69
  70 protected:
  71     gpio_object gpio;
  72
  73     virtual int _putc(int c);
  74     virtual int _getc(void);
  75
  76 }; // End class SerialHalfDuplex
  77
  78 } // End namespace
  79
  80 #endif
  81
  82 #endif