Julien Tiron / AX12

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Dependents:   2-FisherMan 2-FisherMan

Fork of AX12 by Chris Styles

SerialHalfDuplex.cpp@4:c1835649c36f, 2016-05-06 (annotated)

Committer:
julientiron
Date:
Fri May 06 07:21:41 2016 +0000
Revision:
4:c1835649c36f
d

Who changed what in which revision?

UserRevisionLine numberNew contents of line
julientiron 4:c1835649c36f 1 /* mbed Microcontroller Library
julientiron 4:c1835649c36f 2 * Copyright (c) 2006-2012 ARM Limited
julientiron 4:c1835649c36f 3 *
julientiron 4:c1835649c36f 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
julientiron 4:c1835649c36f 5 * of this software and associated documentation files (the "Software"), to deal
julientiron 4:c1835649c36f 6 * in the Software without restriction, including without limitation the rights
julientiron 4:c1835649c36f 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
julientiron 4:c1835649c36f 8 * copies of the Software, and to permit persons to whom the Software is
julientiron 4:c1835649c36f 9 * furnished to do so, subject to the following conditions:
julientiron 4:c1835649c36f 10 *
julientiron 4:c1835649c36f 11 * The above copyright notice and this permission notice shall be included in
julientiron 4:c1835649c36f 12 * all copies or substantial portions of the Software.
julientiron 4:c1835649c36f 13 *
julientiron 4:c1835649c36f 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
julientiron 4:c1835649c36f 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
julientiron 4:c1835649c36f 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
julientiron 4:c1835649c36f 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
julientiron 4:c1835649c36f 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
julientiron 4:c1835649c36f 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
julientiron 4:c1835649c36f 20 * SOFTWARE.
julientiron 4:c1835649c36f 21 *
julientiron 4:c1835649c36f 22 * NOTE: This is an unsupported legacy untested library.
julientiron 4:c1835649c36f 23 */
julientiron 4:c1835649c36f 24 #include "SerialHalfDuplex.h"
julientiron 4:c1835649c36f 25
julientiron 4:c1835649c36f 26 #if DEVICE_SERIAL
julientiron 4:c1835649c36f 27 #include "mbed.h"
julientiron 4:c1835649c36f 28 #include "pinmap.h"
julientiron 4:c1835649c36f 29 #include "serial_api.h"
julientiron 4:c1835649c36f 30 #include "gpio_api.h"
julientiron 4:c1835649c36f 31
julientiron 4:c1835649c36f 32 namespace mbed {
julientiron 4:c1835649c36f 33
julientiron 4:c1835649c36f 34 SerialHalfDuplex::SerialHalfDuplex(PinName tx, PinName rx, const char *name)
julientiron 4:c1835649c36f 35 : Serial(tx, rx, name) {
julientiron 4:c1835649c36f 36 _txpin = tx;
julientiron 4:c1835649c36f 37
julientiron 4:c1835649c36f 38 DigitalIn TXPIN(_txpin); // set as input
julientiron 4:c1835649c36f 39 pin_mode(_txpin, PullNone); // no pull
julientiron 4:c1835649c36f 40 pin_function(_txpin, 0); // set as gpio
julientiron 4:c1835649c36f 41 }
julientiron 4:c1835649c36f 42
julientiron 4:c1835649c36f 43 // To transmit a byte in half duplex mode:
julientiron 4:c1835649c36f 44 // 1. Disable interrupts, so we don't trigger on loopback byte
julientiron 4:c1835649c36f 45 // 2. Set tx pin to UART out
julientiron 4:c1835649c36f 46 // 3. Transmit byte as normal
julientiron 4:c1835649c36f 47 // 4. Read back byte from looped back tx pin - this both confirms that the
julientiron 4:c1835649c36f 48 // transmit has occurred, and also clears the byte from the buffer.
julientiron 4:c1835649c36f 49 // 5. Return pin to input mode
julientiron 4:c1835649c36f 50 // 6. Re-enable interrupts
julientiron 4:c1835649c36f 51
julientiron 4:c1835649c36f 52 int SerialHalfDuplex::_putc(int c) {
julientiron 4:c1835649c36f 53 int retc;
julientiron 4:c1835649c36f 54
julientiron 4:c1835649c36f 55 // TODO: We should not disable all interrupts
julientiron 4:c1835649c36f 56 __disable_irq();
julientiron 4:c1835649c36f 57
julientiron 4:c1835649c36f 58 serial_pinout_tx(_txpin);
julientiron 4:c1835649c36f 59
julientiron 4:c1835649c36f 60 Serial::_putc(c);
julientiron 4:c1835649c36f 61 retc = Serial::getc(); // reading also clears any interrupt
julientiron 4:c1835649c36f 62
julientiron 4:c1835649c36f 63 pin_function(_txpin, 0);
julientiron 4:c1835649c36f 64
julientiron 4:c1835649c36f 65 __enable_irq();
julientiron 4:c1835649c36f 66
julientiron 4:c1835649c36f 67 return retc;
julientiron 4:c1835649c36f 68 }
julientiron 4:c1835649c36f 69
julientiron 4:c1835649c36f 70 int SerialHalfDuplex::_getc(void) {
julientiron 4:c1835649c36f 71 return Serial::_getc();
julientiron 4:c1835649c36f 72 }
julientiron 4:c1835649c36f 73
julientiron 4:c1835649c36f 74 } // End namespace
julientiron 4:c1835649c36f 75
julientiron 4:c1835649c36f 76 #endif