83 lines
2.0 KiB
C
83 lines
2.0 KiB
C
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/* mbed Microcontroller Library - SerialHalfDuplex
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* Copyright (c) 2010-2011 ARM Limited. All rights reserved.
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*/
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#ifndef MBED_SERIALHALFDUPLEX_H
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#define MBED_SERIALHALFDUPLEX_H
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#include "platform.h"
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#if DEVICE_SERIAL
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#include "Serial.h"
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#include "gpio_api.h"
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namespace mbed {
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/** A serial port (UART) for communication with other devices using
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* Half-Duplex, allowing transmit and receive on a single
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* shared transmit and receive line. Only one end should be transmitting
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* at a time.
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*
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* Both the tx and rx pin should be defined, and wired together.
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* This is in addition to them being wired to the other serial
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* device to allow both read and write functions to operate.
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*
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* For Simplex and Full-Duplex Serial communication, see Serial()
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*
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* Example:
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* @code
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* // Send a byte to a second HalfDuplex device, and read the response
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*
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* #include "mbed.h"
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*
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* // p9 and p10 should be wired together to form "a"
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* // p28 and p27 should be wired together to form "b"
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* // p9/p10 should be wired to p28/p27 as the Half Duplex connection
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*
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* SerialHalfDuplex a(p9, p10);
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* SerialHalfDuplex b(p28, p27);
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*
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* void b_rx() { // second device response
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* b.putc(b.getc() + 4);
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* }
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*
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* int main() {
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* b.attach(&b_rx);
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* for (int c = 'A'; c < 'Z'; c++) {
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* a.putc(c);
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* printf("sent [%c]\n", c);
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* wait(0.5); // b should respond
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* if (a.readable()) {
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* printf("received [%c]\n", a.getc());
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* }
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* }
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* }
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* @endcode
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*/
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class SerialHalfDuplex : public Serial {
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public:
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/** Create a half-duplex serial port, connected to the specified transmit
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* and receive pins.
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*
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* These pins should be wired together, as well as to the target device
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*
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* @param tx Transmit pin
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* @param rx Receive pin
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*/
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SerialHalfDuplex(PinName tx, PinName rx);
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protected:
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gpio_object gpio;
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virtual int _putc(int c);
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virtual int _getc(void);
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}; // End class SerialHalfDuplex
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} // End namespace
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#endif
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#endif
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