Tom Soulanille / RTOS-Serial

An RTOS-friendly Serial interface Its primary benefit is that it never hogs the CPU. An amusing alternative to the traditional ring-bufferd interrupt-serviced systems, it uses short mbed-rtos queues to buffer characters to and from the UART, and a thread to service the transmitter. Short interrupt service routines enqueue received characters and signal the transmit thread when the transmitter is available. WARNING: Do not create RTOS-Serial objects before the RTOS is running! Put them inside your main() block or another function, not in the global initialization.

Dependents:   Test_RDM880_rfid_reader

rtos_serial.cpp@8:3644d12758da, 2013-10-22 (annotated)

Committer:
altasoul
Date:
Tue Oct 22 17:38:50 2013 +0000
Revision:
8:3644d12758da
Parent:
7:dd892347b524
Child:
10:d5adca63e94a
Instance method can be attached as ISR so do that

Who changed what in which revision?

UserRevisionLine numberNew contents of line
altasoul 0:0547c8bf304f 1 /*
altasoul 0:0547c8bf304f 2 * Copyright (c) 2013 Tom Soulanille
altasoul 0:0547c8bf304f 3 *
altasoul 0:0547c8bf304f 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
altasoul 0:0547c8bf304f 5 * of this software and associated documentation files (the "Software"), to deal
altasoul 0:0547c8bf304f 6 * in the Software without restriction, including without limitation the rights
altasoul 0:0547c8bf304f 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
altasoul 0:0547c8bf304f 8 * copies of the Software, and to permit persons to whom the Software is
altasoul 0:0547c8bf304f 9 * furnished to do so, subject to the following conditions:
altasoul 0:0547c8bf304f 10 *
altasoul 0:0547c8bf304f 11 * The above copyright notice and this permission notice shall be included in
altasoul 0:0547c8bf304f 12 * all copies or substantial portions of the Software.
altasoul 0:0547c8bf304f 13 *
altasoul 0:0547c8bf304f 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
altasoul 0:0547c8bf304f 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
altasoul 0:0547c8bf304f 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
altasoul 0:0547c8bf304f 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
altasoul 0:0547c8bf304f 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
altasoul 0:0547c8bf304f 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
altasoul 0:0547c8bf304f 20 * SOFTWARE.
altasoul 0:0547c8bf304f 21 */
altasoul 0:0547c8bf304f 22
altasoul 0:0547c8bf304f 23 #include "rtos_serial.h"
altasoul 0:0547c8bf304f 24
altasoul 0:0547c8bf304f 25 RTOS_Serial::RTOS_Serial(PinName tx, PinName rx, const char *name)
altasoul 0:0547c8bf304f 26 : Serial(tx, rx, name)
altasoul 0:0547c8bf304f 27 {
altasoul 5:5d388d1d7987 28 uart_number = get_index();
altasoul 0:0547c8bf304f 29 const PinName leds[] = {LED1,LED2,LED3,LED4};
altasoul 5:5d388d1d7987 30 ledp = new DigitalOut(leds[uart_number]);
altasoul 8:3644d12758da 31 #ifdef RTOS_SERIAL_TX_THREAD
altasoul 0:0547c8bf304f 32 tx_emitter_threadp = new Thread(tx_emitter, (void *) this);
altasoul 8:3644d12758da 33 #endif
altasoul 8:3644d12758da 34 rx_isr_pFP = attach(this, &RTOS_Serial::rx_isr, RxIrq);
altasoul 8:3644d12758da 35 tx_isr_pFP = attach(this, &RTOS_Serial::tx_isr, TxIrq);
altasoul 8:3644d12758da 36 #ifdef RTOS_SERIAL_TX_THREAD
altasoul 2:891773cc33fd 37 tx_emitter_threadp->signal_set(0x01); // "prime the pump" of the tx-ready signals
altasoul 8:3644d12758da 38 #else
altasoul 8:3644d12758da 39 Serial::_putc('*'); //DEBUG
altasoul 8:3644d12758da 40 #endif
altasoul 1:5a66fddad7c4 41 }
altasoul 0:0547c8bf304f 42
altasoul 6:438a6c0acbd4 43
altasoul 6:438a6c0acbd4 44 RTOS_Serial::~RTOS_Serial() {
altasoul 6:438a6c0acbd4 45 remove_handler(rx_isr_pFP, RxIrq);
altasoul 6:438a6c0acbd4 46 remove_handler(tx_isr_pFP, TxIrq);
altasoul 8:3644d12758da 47 #ifdef RTOS_SERIAL_TX_THREAD
altasoul 6:438a6c0acbd4 48 tx_emitter_threadp->terminate();
altasoul 6:438a6c0acbd4 49 delete tx_emitter_threadp;
altasoul 8:3644d12758da 50 #endif
altasoul 6:438a6c0acbd4 51 }
altasoul 6:438a6c0acbd4 52
altasoul 0:0547c8bf304f 53 int RTOS_Serial::get_index() { return _serial.index; }
altasoul 0:0547c8bf304f 54
altasoul 0:0547c8bf304f 55 int RTOS_Serial::putc(int c) {
altasoul 2:891773cc33fd 56 //return Serial::putc(c); //DEBUG
altasoul 0:0547c8bf304f 57 //if (tx_q.put((int *)c, osWaitForever) == osOK) return c; else return EOF;
altasoul 0:0547c8bf304f 58 int status;
altasoul 0:0547c8bf304f 59 if ( (status = tx_q.put((int *)c, osWaitForever)) == osOK) return c; else {
altasoul 5:5d388d1d7987 60 std::printf("\r\nRTOS_Serial::tx_q.put() returned %d\r\n", status);
altasoul 0:0547c8bf304f 61 return EOF;
altasoul 0:0547c8bf304f 62 }
altasoul 0:0547c8bf304f 63 }
altasoul 0:0547c8bf304f 64
altasoul 2:891773cc33fd 65 int RTOS_Serial::puts(const char *s) {
altasoul 2:891773cc33fd 66 int rv = 0;
altasoul 2:891773cc33fd 67 while (*s) {
altasoul 2:891773cc33fd 68 if (putc(*s++) == EOF) {
altasoul 2:891773cc33fd 69 rv = EOF;
altasoul 2:891773cc33fd 70 break;
altasoul 2:891773cc33fd 71 } else {
altasoul 2:891773cc33fd 72 rv++;
altasoul 2:891773cc33fd 73 }
altasoul 2:891773cc33fd 74 }
altasoul 2:891773cc33fd 75 return rv;
altasoul 2:891773cc33fd 76 }
altasoul 2:891773cc33fd 77
altasoul 0:0547c8bf304f 78 int RTOS_Serial::parent_putc(int c) {
altasoul 7:dd892347b524 79 return Serial::_putc(c);
altasoul 0:0547c8bf304f 80 }
altasoul 0:0547c8bf304f 81
altasoul 2:891773cc33fd 82 int RTOS_Serial::getc() {
altasoul 4:c7113cd0ac4b 83 int rv;
altasoul 4:c7113cd0ac4b 84 //return Serial::getc(); //FIXME: stand-in, which fails if we use our RX ISR
altasoul 4:c7113cd0ac4b 85 osEvent evt = rx_q.get();
altasoul 4:c7113cd0ac4b 86 if (evt.status == osEventMessage) {
altasoul 4:c7113cd0ac4b 87 rv = (int) evt.value.v;
altasoul 4:c7113cd0ac4b 88 } else { //FIXME: find appropriate error reporting if any
altasoul 5:5d388d1d7987 89 std::printf("\r\nRTOS_Serial::getc() evt.status %d\n", evt.status);
altasoul 4:c7113cd0ac4b 90 rv = EOF;
altasoul 4:c7113cd0ac4b 91 }
altasoul 4:c7113cd0ac4b 92 return rv;
altasoul 2:891773cc33fd 93 }
altasoul 2:891773cc33fd 94
altasoul 8:3644d12758da 95 void RTOS_Serial::rx_isr(){
altasoul 8:3644d12758da 96 rx_q.put((int *) _getc());
altasoul 1:5a66fddad7c4 97 }
altasoul 1:5a66fddad7c4 98
altasoul 8:3644d12758da 99 void RTOS_Serial::tx_isr(){
altasoul 8:3644d12758da 100 #ifdef RTOS_SERIAL_TX_THREAD
altasoul 8:3644d12758da 101 tx_emitter_threadp->signal_set(0x1);
altasoul 8:3644d12758da 102 #else
altasoul 8:3644d12758da 103 osEvent evt;
altasoul 8:3644d12758da 104 evt = tx_q.get();
altasoul 8:3644d12758da 105 if (evt.status == osEventMessage) {
altasoul 8:3644d12758da 106 *ledp = 1;
altasoul 8:3644d12758da 107 parent_putc(evt.value.v);
altasoul 8:3644d12758da 108 *ledp = 0;
altasoul 8:3644d12758da 109 } /*else {
altasoul 8:3644d12758da 110 std::printf("\r\nRTOS_Serial::tx_emitter() evt.status %d\n", evt.status);
altasoul 8:3644d12758da 111 }*/
altasoul 8:3644d12758da 112 #endif
altasoul 2:891773cc33fd 113 }
altasoul 2:891773cc33fd 114
altasoul 8:3644d12758da 115 #ifdef RTOS_SERIAL_TX_THREAD
altasoul 0:0547c8bf304f 116 // tx_emitter is a class method
altasoul 0:0547c8bf304f 117 void RTOS_Serial::tx_emitter(void const *argument){
altasoul 0:0547c8bf304f 118 RTOS_Serial *sp = (RTOS_Serial *) argument;
altasoul 0:0547c8bf304f 119 osEvent evt;
altasoul 2:891773cc33fd 120 //osStatus status;
altasoul 0:0547c8bf304f 121 while(true){
altasoul 0:0547c8bf304f 122 evt = sp->tx_q.get();
altasoul 0:0547c8bf304f 123 if (evt.status == osEventMessage) {
altasoul 2:891773cc33fd 124 // There is no TX interrupt until the first byte is sent out the port,
altasoul 2:891773cc33fd 125 // so we use a timeout on the signal from the interrupt service routine
altasoul 2:891773cc33fd 126 // and just proceed to transmit the character. This should happen only
altasoul 2:891773cc33fd 127 // once at most, to "prime the pump", but the timeout provides some
altasoul 2:891773cc33fd 128 // safety in case something goes wrong.
altasoul 2:891773cc33fd 129 // A first signal is sent by the RTOS_Serial constructor when the thread
altasoul 2:891773cc33fd 130 // is created, so normally this will not come into effect.
altasoul 2:891773cc33fd 131 // DEBUG: timeout omitted to search for instabilities
altasoul 2:891773cc33fd 132 Thread::signal_wait(0x1/*, 10*/); //FIXME: base the timeout on the baud rate
altasoul 0:0547c8bf304f 133 *(sp->ledp) = 1;
altasoul 0:0547c8bf304f 134 sp->parent_putc(evt.value.v);
altasoul 0:0547c8bf304f 135 *(sp->ledp) = 0;
altasoul 0:0547c8bf304f 136 } else {
altasoul 5:5d388d1d7987 137 std::printf("\r\nRTOS_Serial::tx_emitter() evt.status %d\n", evt.status);
altasoul 0:0547c8bf304f 138 }
altasoul 0:0547c8bf304f 139 *(sp->ledp) = 0;
altasoul 0:0547c8bf304f 140 }
altasoul 3:5865277b7710 141 }
altasoul 8:3644d12758da 142 #endif