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@5:5d388d1d7987, 2013-10-19 (annotated)

Committer:
altasoul
Date:
Sat Oct 19 06:47:12 2013 +0000
Revision:
5:5d388d1d7987
Parent:
4:c7113cd0ac4b
Child:
6:438a6c0acbd4
uart_number = get_index()

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