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@2:891773cc33fd, 2013-10-18 (annotated)

Committer:
altasoul
Date:
Fri Oct 18 06:04:55 2013 +0000
Revision:
2:891773cc33fd
Parent:
1:5a66fddad7c4
Child:
3:5865277b7710
checkpoint before implementing 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 0:0547c8bf304f 28 const PinName leds[] = {LED1,LED2,LED3,LED4};
altasoul 0:0547c8bf304f 29 ledp = new DigitalOut(leds[get_index()]);
altasoul 2:891773cc33fd 30 rsp[get_index()] = this;
altasoul 0:0547c8bf304f 31 tx_emitter_threadp = new Thread(tx_emitter, (void *) this);
altasoul 1:5a66fddad7c4 32 tx_tp[get_index()] = tx_emitter_threadp;
altasoul 2:891773cc33fd 33 attach(tx_isr[get_index()], /*Serial::*/TxIrq);
altasoul 2:891773cc33fd 34 tx_emitter_threadp->signal_set(0x01); // "prime the pump" of the tx-ready signals
altasoul 1:5a66fddad7c4 35 }
altasoul 0:0547c8bf304f 36
altasoul 2:891773cc33fd 37 RTOS_Serial* RTOS_Serial::rsp[4] = { NULL, NULL, NULL, NULL };
altasoul 2:891773cc33fd 38
altasoul 1:5a66fddad7c4 39 serial_t RTOS_Serial::get_serial() { return _serial; }
altasoul 0:0547c8bf304f 40
altasoul 0:0547c8bf304f 41 int RTOS_Serial::get_index() { return _serial.index; }
altasoul 0:0547c8bf304f 42
altasoul 0:0547c8bf304f 43 int RTOS_Serial::putc(int c) {
altasoul 2:891773cc33fd 44 //return Serial::putc(c); //DEBUG
altasoul 0:0547c8bf304f 45 //if (tx_q.put((int *)c, osWaitForever) == osOK) return c; else return EOF;
altasoul 0:0547c8bf304f 46 int status;
altasoul 0:0547c8bf304f 47 if ( (status = tx_q.put((int *)c, osWaitForever)) == osOK) return c; else {
altasoul 0:0547c8bf304f 48 std::printf("tx_q.put() returned %d\r\n", status);
altasoul 0:0547c8bf304f 49 return EOF;
altasoul 0:0547c8bf304f 50 }
altasoul 0:0547c8bf304f 51 }
altasoul 0:0547c8bf304f 52
altasoul 2:891773cc33fd 53 int RTOS_Serial::puts(const char *s) {
altasoul 2:891773cc33fd 54 int rv = 0;
altasoul 2:891773cc33fd 55 while (*s) {
altasoul 2:891773cc33fd 56 if (putc(*s++) == EOF) {
altasoul 2:891773cc33fd 57 rv = EOF;
altasoul 2:891773cc33fd 58 break;
altasoul 2:891773cc33fd 59 } else {
altasoul 2:891773cc33fd 60 rv++;
altasoul 2:891773cc33fd 61 }
altasoul 2:891773cc33fd 62 }
altasoul 2:891773cc33fd 63 return rv;
altasoul 2:891773cc33fd 64 }
altasoul 2:891773cc33fd 65
altasoul 0:0547c8bf304f 66 int RTOS_Serial::parent_putc(int c) {
altasoul 0:0547c8bf304f 67 return Serial::putc(c);
altasoul 0:0547c8bf304f 68 }
altasoul 0:0547c8bf304f 69
altasoul 2:891773cc33fd 70 int RTOS_Serial::getc() {
altasoul 2:891773cc33fd 71 return Serial::getc(); //FIXME: stand-in
altasoul 2:891773cc33fd 72 }
altasoul 2:891773cc33fd 73
altasoul 2:891773cc33fd 74
altasoul 2:891773cc33fd 75 // ISR's for transmitter interrupts
altasoul 0:0547c8bf304f 76 // class method
altasoul 0:0547c8bf304f 77 void RTOS_Serial::UART0_TX_ISR(){
altasoul 2:891773cc33fd 78 //uint32_t IRR = LPC_UART0->IIR;
altasoul 0:0547c8bf304f 79 //tx_emitter_threadp->signal_set(0x1);
altasoul 0:0547c8bf304f 80 tx_tp[0]->signal_set(0x01);
altasoul 0:0547c8bf304f 81 }
altasoul 1:5a66fddad7c4 82 // class method
altasoul 1:5a66fddad7c4 83 void RTOS_Serial::UART1_TX_ISR(){
altasoul 2:891773cc33fd 84 //uint32_t IRR = LPC_UART1->IIR;
altasoul 1:5a66fddad7c4 85 //tx_emitter_threadp->signal_set(0x1);
altasoul 1:5a66fddad7c4 86 tx_tp[1]->signal_set(0x01);
altasoul 1:5a66fddad7c4 87 }
altasoul 1:5a66fddad7c4 88 // class method
altasoul 1:5a66fddad7c4 89 void RTOS_Serial::UART2_TX_ISR(){
altasoul 2:891773cc33fd 90 //uint32_t IRR = LPC_UART2->IIR;
altasoul 1:5a66fddad7c4 91 //tx_emitter_threadp->signal_set(0x1);
altasoul 1:5a66fddad7c4 92 tx_tp[2]->signal_set(0x01);
altasoul 1:5a66fddad7c4 93 }
altasoul 1:5a66fddad7c4 94 // class method
altasoul 1:5a66fddad7c4 95 void RTOS_Serial::UART3_TX_ISR(){
altasoul 2:891773cc33fd 96 //uint32_t IRR = LPC_UART3->IIR;
altasoul 1:5a66fddad7c4 97 //tx_emitter_threadp->signal_set(0x1);
altasoul 1:5a66fddad7c4 98 tx_tp[3]->signal_set(0x01);
altasoul 1:5a66fddad7c4 99 }
altasoul 1:5a66fddad7c4 100
altasoul 1:5a66fddad7c4 101 func RTOS_Serial::tx_isr[4] = {
altasoul 1:5a66fddad7c4 102 &RTOS_Serial::UART0_TX_ISR,
altasoul 1:5a66fddad7c4 103 &RTOS_Serial::UART1_TX_ISR,
altasoul 1:5a66fddad7c4 104 &RTOS_Serial::UART2_TX_ISR,
altasoul 1:5a66fddad7c4 105 &RTOS_Serial::UART3_TX_ISR,
altasoul 1:5a66fddad7c4 106 };
altasoul 1:5a66fddad7c4 107
altasoul 2:891773cc33fd 108 /// ISR's for receiver interrupts
altasoul 2:891773cc33fd 109 // class method
altasoul 2:891773cc33fd 110 void RTOS_Serial::UART0_RX_ISR(){
altasoul 2:891773cc33fd 111 RTOS_Serial::rsp[0]->rx_q.put((int *)LPC_UART0->RBR);
altasoul 2:891773cc33fd 112 }
altasoul 2:891773cc33fd 113 // class method
altasoul 2:891773cc33fd 114 void RTOS_Serial::UART1_RX_ISR(){
altasoul 2:891773cc33fd 115 RTOS_Serial::rsp[1]->rx_q.put((int *)LPC_UART1->RBR);
altasoul 2:891773cc33fd 116 }
altasoul 2:891773cc33fd 117 // class method
altasoul 2:891773cc33fd 118 void RTOS_Serial::UART2_RX_ISR(){
altasoul 2:891773cc33fd 119 RTOS_Serial::rsp[2]->rx_q.put((int *)LPC_UART2->RBR);
altasoul 2:891773cc33fd 120 }
altasoul 2:891773cc33fd 121 // class method
altasoul 2:891773cc33fd 122 void RTOS_Serial::UART3_RX_ISR(){
altasoul 2:891773cc33fd 123 RTOS_Serial::rsp[3]->rx_q.put((int *)LPC_UART3->RBR);
altasoul 2:891773cc33fd 124 }
altasoul 2:891773cc33fd 125
altasoul 2:891773cc33fd 126 func RTOS_Serial::rx_isr[4] = {
altasoul 2:891773cc33fd 127 &RTOS_Serial::UART0_RX_ISR,
altasoul 2:891773cc33fd 128 &RTOS_Serial::UART1_RX_ISR,
altasoul 2:891773cc33fd 129 &RTOS_Serial::UART2_RX_ISR,
altasoul 2:891773cc33fd 130 &RTOS_Serial::UART3_RX_ISR,
altasoul 2:891773cc33fd 131 };
altasoul 2:891773cc33fd 132
altasoul 1:5a66fddad7c4 133 Thread* RTOS_Serial::tx_tp[4] = { NULL, NULL, NULL, NULL };
altasoul 0:0547c8bf304f 134
altasoul 0:0547c8bf304f 135 // tx_emitter is a class method
altasoul 0:0547c8bf304f 136 void RTOS_Serial::tx_emitter(void const *argument){
altasoul 0:0547c8bf304f 137 RTOS_Serial *sp = (RTOS_Serial *) argument;
altasoul 0:0547c8bf304f 138 osEvent evt;
altasoul 2:891773cc33fd 139 //osStatus status;
altasoul 0:0547c8bf304f 140 while(true){
altasoul 0:0547c8bf304f 141 evt = sp->tx_q.get();
altasoul 0:0547c8bf304f 142 if (evt.status == osEventMessage) {
altasoul 2:891773cc33fd 143 // There is no TX interrupt until the first byte is sent out the port,
altasoul 2:891773cc33fd 144 // so we use a timeout on the signal from the interrupt service routine
altasoul 2:891773cc33fd 145 // and just proceed to transmit the character. This should happen only
altasoul 2:891773cc33fd 146 // once at most, to "prime the pump", but the timeout provides some
altasoul 2:891773cc33fd 147 // safety in case something goes wrong.
altasoul 2:891773cc33fd 148 // A first signal is sent by the RTOS_Serial constructor when the thread
altasoul 2:891773cc33fd 149 // is created, so normally this will not come into effect.
altasoul 2:891773cc33fd 150 // DEBUG: timeout omitted to search for instabilities
altasoul 2:891773cc33fd 151 Thread::signal_wait(0x1/*, 10*/); //FIXME: base the timeout on the baud rate
altasoul 0:0547c8bf304f 152 *(sp->ledp) = 1;
altasoul 0:0547c8bf304f 153 sp->parent_putc(evt.value.v);
altasoul 0:0547c8bf304f 154 *(sp->ledp) = 0;
altasoul 0:0547c8bf304f 155 } else {
altasoul 0:0547c8bf304f 156 std::printf("tx_emitter() evt.status %d\n", evt.status);
altasoul 0:0547c8bf304f 157 }
altasoul 0:0547c8bf304f 158 *(sp->ledp) = 0;
altasoul 0:0547c8bf304f 159 }
altasoul 0:0547c8bf304f 160 }