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@7:dd892347b524, 2013-10-21 (annotated)

Committer:
altasoul
Date:
Mon Oct 21 22:58:04 2013 +0000
Revision:
7:dd892347b524
Parent:
6:438a6c0acbd4
Child:
8:3644d12758da
#ifdef underscore_putc, _getc

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 5:5d388d1d7987 31 rtos_serial_pointers_by_index[uart_number] = this;
altasoul 0:0547c8bf304f 32 tx_emitter_threadp = new Thread(tx_emitter, (void *) this);
altasoul 5:5d388d1d7987 33 tx_tp[uart_number] = tx_emitter_threadp;
altasoul 6:438a6c0acbd4 34 rx_isr_pFP = attach(rx_isr[uart_number], RxIrq);
altasoul 6:438a6c0acbd4 35 tx_isr_pFP = attach(tx_isr[uart_number], TxIrq);
altasoul 2:891773cc33fd 36 tx_emitter_threadp->signal_set(0x01); // "prime the pump" of the tx-ready signals
altasoul 1:5a66fddad7c4 37 }
altasoul 0:0547c8bf304f 38
altasoul 6:438a6c0acbd4 39
altasoul 6:438a6c0acbd4 40 RTOS_Serial::~RTOS_Serial() {
altasoul 6:438a6c0acbd4 41 remove_handler(rx_isr_pFP, RxIrq);
altasoul 6:438a6c0acbd4 42 remove_handler(tx_isr_pFP, TxIrq);
altasoul 6:438a6c0acbd4 43 tx_emitter_threadp->terminate();
altasoul 6:438a6c0acbd4 44 tx_tp[uart_number] = NULL;
altasoul 6:438a6c0acbd4 45 delete tx_emitter_threadp;
altasoul 6:438a6c0acbd4 46 rtos_serial_pointers_by_index[uart_number] = NULL;
altasoul 6:438a6c0acbd4 47 }
altasoul 6:438a6c0acbd4 48
altasoul 4:c7113cd0ac4b 49 RTOS_Serial* RTOS_Serial::rtos_serial_pointers_by_index[4] = { NULL, NULL, NULL, NULL };
altasoul 2:891773cc33fd 50
altasoul 1:5a66fddad7c4 51 serial_t RTOS_Serial::get_serial() { return _serial; }
altasoul 0:0547c8bf304f 52
altasoul 0:0547c8bf304f 53 int RTOS_Serial::get_index() { return _serial.index; }
altasoul 0:0547c8bf304f 54
altasoul 7:dd892347b524 55 #ifdef RTOS_Serial_underscore_putc
altasoul 7:dd892347b524 56 int RTOS_Serial::_putc(int c) {
altasoul 7:dd892347b524 57 #else
altasoul 0:0547c8bf304f 58 int RTOS_Serial::putc(int c) {
altasoul 7:dd892347b524 59 #endif
altasoul 2:891773cc33fd 60 //return Serial::putc(c); //DEBUG
altasoul 0:0547c8bf304f 61 //if (tx_q.put((int *)c, osWaitForever) == osOK) return c; else return EOF;
altasoul 0:0547c8bf304f 62 int status;
altasoul 0:0547c8bf304f 63 if ( (status = tx_q.put((int *)c, osWaitForever)) == osOK) return c; else {
altasoul 5:5d388d1d7987 64 std::printf("\r\nRTOS_Serial::tx_q.put() returned %d\r\n", status);
altasoul 0:0547c8bf304f 65 return EOF;
altasoul 0:0547c8bf304f 66 }
altasoul 0:0547c8bf304f 67 }
altasoul 0:0547c8bf304f 68
altasoul 2:891773cc33fd 69 int RTOS_Serial::puts(const char *s) {
altasoul 2:891773cc33fd 70 int rv = 0;
altasoul 2:891773cc33fd 71 while (*s) {
altasoul 2:891773cc33fd 72 if (putc(*s++) == EOF) {
altasoul 2:891773cc33fd 73 rv = EOF;
altasoul 2:891773cc33fd 74 break;
altasoul 2:891773cc33fd 75 } else {
altasoul 2:891773cc33fd 76 rv++;
altasoul 2:891773cc33fd 77 }
altasoul 2:891773cc33fd 78 }
altasoul 2:891773cc33fd 79 return rv;
altasoul 2:891773cc33fd 80 }
altasoul 2:891773cc33fd 81
altasoul 0:0547c8bf304f 82 int RTOS_Serial::parent_putc(int c) {
altasoul 7:dd892347b524 83 #ifdef RTOS_Serial_underscore_putc
altasoul 7:dd892347b524 84 return Serial::_putc(c);
altasoul 7:dd892347b524 85 #else
altasoul 0:0547c8bf304f 86 return Serial::putc(c);
altasoul 7:dd892347b524 87 #endif
altasoul 0:0547c8bf304f 88 }
altasoul 0:0547c8bf304f 89
altasoul 7:dd892347b524 90 #ifdef RTOS_Serial_underscore_getc
altasoul 7:dd892347b524 91 int RTOS_Serial::_getc() {
altasoul 7:dd892347b524 92 #else
altasoul 2:891773cc33fd 93 int RTOS_Serial::getc() {
altasoul 7:dd892347b524 94 #endif
altasoul 4:c7113cd0ac4b 95 int rv;
altasoul 4:c7113cd0ac4b 96 //return Serial::getc(); //FIXME: stand-in, which fails if we use our RX ISR
altasoul 4:c7113cd0ac4b 97 osEvent evt = rx_q.get();
altasoul 4:c7113cd0ac4b 98 if (evt.status == osEventMessage) {
altasoul 4:c7113cd0ac4b 99 rv = (int) evt.value.v;
altasoul 4:c7113cd0ac4b 100 } else { //FIXME: find appropriate error reporting if any
altasoul 5:5d388d1d7987 101 std::printf("\r\nRTOS_Serial::getc() evt.status %d\n", evt.status);
altasoul 4:c7113cd0ac4b 102 rv = EOF;
altasoul 4:c7113cd0ac4b 103 }
altasoul 4:c7113cd0ac4b 104 return rv;
altasoul 2:891773cc33fd 105 }
altasoul 2:891773cc33fd 106
altasoul 2:891773cc33fd 107
altasoul 2:891773cc33fd 108 // ISR's for transmitter interrupts
altasoul 0:0547c8bf304f 109 // class method
altasoul 0:0547c8bf304f 110 void RTOS_Serial::UART0_TX_ISR(){
altasoul 2:891773cc33fd 111 //uint32_t IRR = LPC_UART0->IIR;
altasoul 0:0547c8bf304f 112 //tx_emitter_threadp->signal_set(0x1);
altasoul 0:0547c8bf304f 113 tx_tp[0]->signal_set(0x01);
altasoul 0:0547c8bf304f 114 }
altasoul 1:5a66fddad7c4 115 // class method
altasoul 1:5a66fddad7c4 116 void RTOS_Serial::UART1_TX_ISR(){
altasoul 2:891773cc33fd 117 //uint32_t IRR = LPC_UART1->IIR;
altasoul 1:5a66fddad7c4 118 //tx_emitter_threadp->signal_set(0x1);
altasoul 1:5a66fddad7c4 119 tx_tp[1]->signal_set(0x01);
altasoul 1:5a66fddad7c4 120 }
altasoul 1:5a66fddad7c4 121 // class method
altasoul 1:5a66fddad7c4 122 void RTOS_Serial::UART2_TX_ISR(){
altasoul 2:891773cc33fd 123 //uint32_t IRR = LPC_UART2->IIR;
altasoul 1:5a66fddad7c4 124 //tx_emitter_threadp->signal_set(0x1);
altasoul 1:5a66fddad7c4 125 tx_tp[2]->signal_set(0x01);
altasoul 1:5a66fddad7c4 126 }
altasoul 1:5a66fddad7c4 127 // class method
altasoul 1:5a66fddad7c4 128 void RTOS_Serial::UART3_TX_ISR(){
altasoul 7:dd892347b524 129 //uint32_t IRR = LPC_UART3->IIR; //DEBUG: maybe this?
altasoul 1:5a66fddad7c4 130 //tx_emitter_threadp->signal_set(0x1);
altasoul 1:5a66fddad7c4 131 tx_tp[3]->signal_set(0x01);
altasoul 1:5a66fddad7c4 132 }
altasoul 1:5a66fddad7c4 133
altasoul 1:5a66fddad7c4 134 func RTOS_Serial::tx_isr[4] = {
altasoul 1:5a66fddad7c4 135 &RTOS_Serial::UART0_TX_ISR,
altasoul 1:5a66fddad7c4 136 &RTOS_Serial::UART1_TX_ISR,
altasoul 1:5a66fddad7c4 137 &RTOS_Serial::UART2_TX_ISR,
altasoul 1:5a66fddad7c4 138 &RTOS_Serial::UART3_TX_ISR,
altasoul 1:5a66fddad7c4 139 };
altasoul 1:5a66fddad7c4 140
altasoul 2:891773cc33fd 141 /// ISR's for receiver interrupts
altasoul 2:891773cc33fd 142 // class method
altasoul 2:891773cc33fd 143 void RTOS_Serial::UART0_RX_ISR(){
altasoul 4:c7113cd0ac4b 144 RTOS_Serial::rtos_serial_pointers_by_index[0]->rx_q.put((int *)LPC_UART0->RBR);
altasoul 2:891773cc33fd 145 }
altasoul 2:891773cc33fd 146 // class method
altasoul 2:891773cc33fd 147 void RTOS_Serial::UART1_RX_ISR(){
altasoul 4:c7113cd0ac4b 148 RTOS_Serial::rtos_serial_pointers_by_index[1]->rx_q.put((int *)LPC_UART1->RBR);
altasoul 2:891773cc33fd 149 }
altasoul 2:891773cc33fd 150 // class method
altasoul 2:891773cc33fd 151 void RTOS_Serial::UART2_RX_ISR(){
altasoul 4:c7113cd0ac4b 152 RTOS_Serial::rtos_serial_pointers_by_index[2]->rx_q.put((int *)LPC_UART2->RBR);
altasoul 2:891773cc33fd 153 }
altasoul 2:891773cc33fd 154 // class method
altasoul 2:891773cc33fd 155 void RTOS_Serial::UART3_RX_ISR(){
altasoul 4:c7113cd0ac4b 156 RTOS_Serial::rtos_serial_pointers_by_index[3]->rx_q.put((int *)LPC_UART3->RBR);
altasoul 2:891773cc33fd 157 }
altasoul 2:891773cc33fd 158
altasoul 2:891773cc33fd 159 func RTOS_Serial::rx_isr[4] = {
altasoul 2:891773cc33fd 160 &RTOS_Serial::UART0_RX_ISR,
altasoul 2:891773cc33fd 161 &RTOS_Serial::UART1_RX_ISR,
altasoul 2:891773cc33fd 162 &RTOS_Serial::UART2_RX_ISR,
altasoul 2:891773cc33fd 163 &RTOS_Serial::UART3_RX_ISR,
altasoul 2:891773cc33fd 164 };
altasoul 2:891773cc33fd 165
altasoul 1:5a66fddad7c4 166 Thread* RTOS_Serial::tx_tp[4] = { NULL, NULL, NULL, NULL };
altasoul 0:0547c8bf304f 167
altasoul 0:0547c8bf304f 168 // tx_emitter is a class method
altasoul 0:0547c8bf304f 169 void RTOS_Serial::tx_emitter(void const *argument){
altasoul 0:0547c8bf304f 170 RTOS_Serial *sp = (RTOS_Serial *) argument;
altasoul 0:0547c8bf304f 171 osEvent evt;
altasoul 2:891773cc33fd 172 //osStatus status;
altasoul 0:0547c8bf304f 173 while(true){
altasoul 0:0547c8bf304f 174 evt = sp->tx_q.get();
altasoul 0:0547c8bf304f 175 if (evt.status == osEventMessage) {
altasoul 2:891773cc33fd 176 // There is no TX interrupt until the first byte is sent out the port,
altasoul 2:891773cc33fd 177 // so we use a timeout on the signal from the interrupt service routine
altasoul 2:891773cc33fd 178 // and just proceed to transmit the character. This should happen only
altasoul 2:891773cc33fd 179 // once at most, to "prime the pump", but the timeout provides some
altasoul 2:891773cc33fd 180 // safety in case something goes wrong.
altasoul 2:891773cc33fd 181 // A first signal is sent by the RTOS_Serial constructor when the thread
altasoul 2:891773cc33fd 182 // is created, so normally this will not come into effect.
altasoul 2:891773cc33fd 183 // DEBUG: timeout omitted to search for instabilities
altasoul 2:891773cc33fd 184 Thread::signal_wait(0x1/*, 10*/); //FIXME: base the timeout on the baud rate
altasoul 0:0547c8bf304f 185 *(sp->ledp) = 1;
altasoul 0:0547c8bf304f 186 sp->parent_putc(evt.value.v);
altasoul 0:0547c8bf304f 187 *(sp->ledp) = 0;
altasoul 0:0547c8bf304f 188 } else {
altasoul 5:5d388d1d7987 189 std::printf("\r\nRTOS_Serial::tx_emitter() evt.status %d\n", evt.status);
altasoul 0:0547c8bf304f 190 }
altasoul 0:0547c8bf304f 191 *(sp->ledp) = 0;
altasoul 0:0547c8bf304f 192 }
altasoul 3:5865277b7710 193 }