Tyler Weaver / buffered-serial1

UART1 buffered serial driver, requires RTOS

Dependents:   Serial_interrupts_buffered HARP2 HARP3

Buffered serial UART1 - Setup to work with UART1 (p13,p14)

Uses RTOS to block current thread.

Reference: http://mbed.org/users/tylerjw/notebook/buffered-serial-with-rtos/

buffered_serial.cpp@1:eabb26ce183b, 2012-12-11 (annotated)

Committer:
tylerjw
Date:
Tue Dec 11 00:08:24 2012 +0000
Revision:
1:eabb26ce183b
Parent:
0:707b9f3904dd
Child:
2:8ccf9bb8dc65
fixed end of line detection

Who changed what in which revision?

UserRevisionLine numberNew contents of line
tylerjw 0:707b9f3904dd 1 #include "buffered_serial.h"
tylerjw 0:707b9f3904dd 2
tylerjw 0:707b9f3904dd 3 BufferedSerial::BufferedSerial(PinName tx, PinName rx) : Serial(tx,rx), led1(LED1), led2(LED2), rx_sem(0), tx_sem(0)
tylerjw 0:707b9f3904dd 4 {
tylerjw 0:707b9f3904dd 5 tx_in=0;
tylerjw 0:707b9f3904dd 6 tx_out=0;
tylerjw 0:707b9f3904dd 7 rx_in=0;
tylerjw 0:707b9f3904dd 8 rx_out=0;
tylerjw 0:707b9f3904dd 9
tylerjw 0:707b9f3904dd 10 device_irqn = UART1_IRQn;
tylerjw 0:707b9f3904dd 11
tylerjw 0:707b9f3904dd 12 // attach the interrupts
tylerjw 0:707b9f3904dd 13 Serial::attach(this, &BufferedSerial::Rx_interrupt, Serial::RxIrq);
tylerjw 0:707b9f3904dd 14 Serial::attach(this, &BufferedSerial::Tx_interrupt, Serial::TxIrq);
tylerjw 0:707b9f3904dd 15 }
tylerjw 0:707b9f3904dd 16
tylerjw 0:707b9f3904dd 17 // Copy tx line buffer to large tx buffer for tx interrupt routine
tylerjw 0:707b9f3904dd 18 void BufferedSerial::send_line(char *c)
tylerjw 0:707b9f3904dd 19 {
tylerjw 0:707b9f3904dd 20 int i;
tylerjw 0:707b9f3904dd 21 char temp_char;
tylerjw 0:707b9f3904dd 22 bool empty;
tylerjw 0:707b9f3904dd 23 i = 0;
tylerjw 0:707b9f3904dd 24 strncpy(tx_line,c,LINE_SIZE);
tylerjw 0:707b9f3904dd 25 // Start Critical Section - don't interrupt while changing global buffer variables
tylerjw 0:707b9f3904dd 26 NVIC_DisableIRQ(device_irqn);
tylerjw 0:707b9f3904dd 27 empty = (tx_in == tx_out);
tylerjw 0:707b9f3904dd 28 while ((i==0) || (tx_line[i-1] != '\n')) {
tylerjw 0:707b9f3904dd 29 // Wait if buffer full
tylerjw 0:707b9f3904dd 30 if (IS_TX_FULL) {
tylerjw 0:707b9f3904dd 31 // End Critical Section - need to let interrupt routine empty buffer by sending
tylerjw 0:707b9f3904dd 32 NVIC_EnableIRQ(device_irqn);
tylerjw 0:707b9f3904dd 33 //while (IS_TX_FULL) ; // buffer is full
tylerjw 0:707b9f3904dd 34 tx_sem.wait();
tylerjw 0:707b9f3904dd 35 // Start Critical Section - don't interrupt while changing global buffer variables
tylerjw 0:707b9f3904dd 36 NVIC_DisableIRQ(device_irqn);
tylerjw 0:707b9f3904dd 37 }
tylerjw 0:707b9f3904dd 38 tx_buffer[tx_in] = tx_line[i];
tylerjw 0:707b9f3904dd 39 i++;
tylerjw 0:707b9f3904dd 40 tx_in = NEXT(tx_in);
tylerjw 0:707b9f3904dd 41 }
tylerjw 0:707b9f3904dd 42 if (Serial::writeable() && (empty)) {
tylerjw 0:707b9f3904dd 43 temp_char = tx_buffer[tx_out];
tylerjw 0:707b9f3904dd 44 tx_out = NEXT(tx_out);
tylerjw 0:707b9f3904dd 45 // Send first character to start tx interrupts, if stopped
tylerjw 0:707b9f3904dd 46 LPC_UART1->THR = temp_char;
tylerjw 0:707b9f3904dd 47 }
tylerjw 0:707b9f3904dd 48 // End Critical Section
tylerjw 0:707b9f3904dd 49 NVIC_EnableIRQ(device_irqn);
tylerjw 0:707b9f3904dd 50 }
tylerjw 0:707b9f3904dd 51
tylerjw 0:707b9f3904dd 52 // Read a line from the large rx buffer from rx interrupt routine
tylerjw 0:707b9f3904dd 53 void BufferedSerial::read_line(char *c)
tylerjw 0:707b9f3904dd 54 {
tylerjw 0:707b9f3904dd 55 int i;
tylerjw 0:707b9f3904dd 56 i = 0;
tylerjw 0:707b9f3904dd 57 // Start Critical Section - don't interrupt while changing global buffer variables
tylerjw 0:707b9f3904dd 58 NVIC_DisableIRQ(device_irqn);
tylerjw 1:eabb26ce183b 59 memset(rx_line,LINE_SIZE,0);
tylerjw 0:707b9f3904dd 60 // Loop reading rx buffer characters until end of line character
tylerjw 1:eabb26ce183b 61 while ((i==0) || (rx_line[i-1] != '\n')) {
tylerjw 0:707b9f3904dd 62 // Wait if buffer empty
tylerjw 0:707b9f3904dd 63 if (IS_RX_EMPTY) { // buffer empty
tylerjw 0:707b9f3904dd 64 // End Critical Section - need to allow rx interrupt to get new characters for buffer
tylerjw 0:707b9f3904dd 65 NVIC_EnableIRQ(device_irqn);
tylerjw 0:707b9f3904dd 66 //while (rx_in == rx_out) ; // buffer empty
tylerjw 0:707b9f3904dd 67 rx_sem.wait();
tylerjw 0:707b9f3904dd 68 // Start Critical Section - don't interrupt while changing global buffer variables
tylerjw 0:707b9f3904dd 69 NVIC_DisableIRQ(device_irqn);
tylerjw 0:707b9f3904dd 70 } else {
tylerjw 0:707b9f3904dd 71 rx_sem.wait();
tylerjw 0:707b9f3904dd 72 }
tylerjw 0:707b9f3904dd 73 rx_line[i] = rx_buffer[rx_out];
tylerjw 0:707b9f3904dd 74 i++;
tylerjw 0:707b9f3904dd 75 rx_out = NEXT(rx_out);
tylerjw 1:eabb26ce183b 76
tylerjw 1:eabb26ce183b 77 // prevent overflow on rx_line
tylerjw 1:eabb26ce183b 78 /*if(i >= (LINE_SIZE - 1)) // not working!!!
tylerjw 1:eabb26ce183b 79 {
tylerjw 1:eabb26ce183b 80 i--;
tylerjw 1:eabb26ce183b 81 break;
tylerjw 1:eabb26ce183b 82 }*/
tylerjw 0:707b9f3904dd 83 }
tylerjw 1:eabb26ce183b 84 rx_line[i++] = 0;
tylerjw 0:707b9f3904dd 85 // End Critical Section
tylerjw 0:707b9f3904dd 86 NVIC_EnableIRQ(device_irqn);
tylerjw 1:eabb26ce183b 87 strncpy(c,rx_line,i);
tylerjw 0:707b9f3904dd 88 }
tylerjw 0:707b9f3904dd 89
tylerjw 0:707b9f3904dd 90 // Interupt Routine to read in data from serial port
tylerjw 0:707b9f3904dd 91 void BufferedSerial::Rx_interrupt()
tylerjw 0:707b9f3904dd 92 {
tylerjw 0:707b9f3904dd 93 uint32_t IRR1 = LPC_UART1->IIR;
tylerjw 0:707b9f3904dd 94 led1=1;
tylerjw 0:707b9f3904dd 95 while (readable() && !(IS_RX_FULL)) {
tylerjw 0:707b9f3904dd 96 rx_buffer[rx_in] = LPC_UART1->RBR;
tylerjw 0:707b9f3904dd 97 rx_in = NEXT(rx_in);
tylerjw 0:707b9f3904dd 98 rx_sem.release();
tylerjw 0:707b9f3904dd 99 }
tylerjw 0:707b9f3904dd 100 led1=0;
tylerjw 0:707b9f3904dd 101 }
tylerjw 0:707b9f3904dd 102
tylerjw 0:707b9f3904dd 103 // Interupt Routine to write out data to serial port
tylerjw 0:707b9f3904dd 104 void BufferedSerial::Tx_interrupt()
tylerjw 0:707b9f3904dd 105 {
tylerjw 0:707b9f3904dd 106 uint32_t IRR = LPC_UART1->IIR;
tylerjw 0:707b9f3904dd 107 led2=1;
tylerjw 0:707b9f3904dd 108 while ((writeable()) && (tx_in != tx_out)) { // while serial is writeable and there are still characters in the buffer
tylerjw 0:707b9f3904dd 109 LPC_UART1->THR = tx_buffer[tx_out]; // send the character
tylerjw 0:707b9f3904dd 110 tx_out = NEXT(tx_out);
tylerjw 0:707b9f3904dd 111 }
tylerjw 0:707b9f3904dd 112 if(!IS_TX_FULL) // if not full
tylerjw 0:707b9f3904dd 113 tx_sem.release();
tylerjw 0:707b9f3904dd 114 led2=0;
tylerjw 0:707b9f3904dd 115 }