Ninad Chitnis / BufferedSerial

Inherit from Serial and use software buffers for TX and RX. This allows the UART peripherals to operate in a IRQ driven mode. Overrides most (but not all) stdio functions as Serial did

Dependencies:   Buffer

Fork of BufferedSerial by Sam Grove

BufferedSerial.cpp@6:8287e83943f0, 2014-09-09 (annotated)

Committer:
ansond
Date:
Tue Sep 09 20:20:38 2014 +0000
Revision:
6:8287e83943f0
Parent:
4:2ba4d2e1f05d
Child:
7:6fa214b41d73
added #define to change the base Serial class to RawSerial if desired

Who changed what in which revision?

UserRevisionLine numberNew contents of line
sam_grove 0:a977d0a3d81e 1 /**
sam_grove 0:a977d0a3d81e 2 * @file BufferedSerial.cpp
sam_grove 0:a977d0a3d81e 3 * @brief Software Buffer - Extends mbed Serial functionallity adding irq driven TX and RX
sam_grove 0:a977d0a3d81e 4 * @author sam grove
sam_grove 0:a977d0a3d81e 5 * @version 1.0
sam_grove 4:2ba4d2e1f05d 6 * @see
sam_grove 0:a977d0a3d81e 7 *
sam_grove 0:a977d0a3d81e 8 * Copyright (c) 2013
sam_grove 0:a977d0a3d81e 9 *
sam_grove 0:a977d0a3d81e 10 * Licensed under the Apache License, Version 2.0 (the "License");
sam_grove 0:a977d0a3d81e 11 * you may not use this file except in compliance with the License.
sam_grove 0:a977d0a3d81e 12 * You may obtain a copy of the License at
sam_grove 0:a977d0a3d81e 13 *
sam_grove 0:a977d0a3d81e 14 * http://www.apache.org/licenses/LICENSE-2.0
sam_grove 0:a977d0a3d81e 15 *
sam_grove 0:a977d0a3d81e 16 * Unless required by applicable law or agreed to in writing, software
sam_grove 0:a977d0a3d81e 17 * distributed under the License is distributed on an "AS IS" BASIS,
sam_grove 0:a977d0a3d81e 18 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
sam_grove 0:a977d0a3d81e 19 * See the License for the specific language governing permissions and
sam_grove 0:a977d0a3d81e 20 * limitations under the License.
sam_grove 0:a977d0a3d81e 21 */
sam_grove 0:a977d0a3d81e 22
sam_grove 0:a977d0a3d81e 23 #include "BufferedSerial.h"
sam_grove 0:a977d0a3d81e 24 #include <stdarg.h>
sam_grove 0:a977d0a3d81e 25
sam_grove 0:a977d0a3d81e 26 BufferedSerial::BufferedSerial(PinName tx, PinName rx, const char* name)
ansond 6:8287e83943f0 27 : SERIAL_BASE(tx, rx)
sam_grove 0:a977d0a3d81e 28 {
ansond 6:8287e83943f0 29 SERIAL_BASE::attach(this, &BufferedSerial::rxIrq, Serial::RxIrq);
sam_grove 4:2ba4d2e1f05d 30
sam_grove 0:a977d0a3d81e 31 return;
sam_grove 0:a977d0a3d81e 32 }
sam_grove 0:a977d0a3d81e 33
sam_grove 0:a977d0a3d81e 34 BufferedSerial::~BufferedSerial(void)
sam_grove 0:a977d0a3d81e 35 {
ansond 6:8287e83943f0 36 SERIAL_BASE::attach(NULL, SERIAL_BASE::RxIrq);
ansond 6:8287e83943f0 37 SERIAL_BASE::attach(NULL, SERIAL_BASE::TxIrq);
sam_grove 4:2ba4d2e1f05d 38
sam_grove 0:a977d0a3d81e 39 return;
sam_grove 0:a977d0a3d81e 40 }
sam_grove 0:a977d0a3d81e 41
sam_grove 0:a977d0a3d81e 42 int BufferedSerial::readable(void)
sam_grove 0:a977d0a3d81e 43 {
sam_grove 0:a977d0a3d81e 44 return _rxbuf.available(); // note: look if things are in the buffer
sam_grove 0:a977d0a3d81e 45 }
sam_grove 0:a977d0a3d81e 46
sam_grove 0:a977d0a3d81e 47 int BufferedSerial::writeable(void)
sam_grove 0:a977d0a3d81e 48 {
sam_grove 0:a977d0a3d81e 49 return 1; // buffer allows overwriting by design, always true
sam_grove 0:a977d0a3d81e 50 }
sam_grove 0:a977d0a3d81e 51
sam_grove 0:a977d0a3d81e 52 int BufferedSerial::getc(void)
sam_grove 0:a977d0a3d81e 53 {
sam_grove 3:6b76fcf27545 54 return _rxbuf;
sam_grove 0:a977d0a3d81e 55 }
sam_grove 0:a977d0a3d81e 56
sam_grove 0:a977d0a3d81e 57 int BufferedSerial::putc(int c)
sam_grove 0:a977d0a3d81e 58 {
sam_grove 0:a977d0a3d81e 59 _txbuf = (char)c;
sam_grove 1:57a11fb5d529 60 BufferedSerial::prime();
sam_grove 4:2ba4d2e1f05d 61
sam_grove 0:a977d0a3d81e 62 return c;
sam_grove 0:a977d0a3d81e 63 }
sam_grove 0:a977d0a3d81e 64
sam_grove 0:a977d0a3d81e 65 int BufferedSerial::puts(const char *s)
sam_grove 0:a977d0a3d81e 66 {
sam_grove 2:7e8a450a9101 67 const char* ptr = s;
sam_grove 4:2ba4d2e1f05d 68
sam_grove 4:2ba4d2e1f05d 69 while(*(ptr) != 0) {
sam_grove 2:7e8a450a9101 70 _txbuf = *(ptr++);
sam_grove 0:a977d0a3d81e 71 }
sam_grove 2:7e8a450a9101 72 _txbuf = '\n'; // done per puts definition
sam_grove 1:57a11fb5d529 73 BufferedSerial::prime();
sam_grove 4:2ba4d2e1f05d 74
sam_grove 2:7e8a450a9101 75 return (ptr - s) + 1;
sam_grove 0:a977d0a3d81e 76 }
sam_grove 0:a977d0a3d81e 77
sam_grove 0:a977d0a3d81e 78 int BufferedSerial::printf(const char* format, ...)
sam_grove 0:a977d0a3d81e 79 {
sam_grove 0:a977d0a3d81e 80 char buf[256] = {0};
sam_grove 0:a977d0a3d81e 81 int r = 0;
sam_grove 4:2ba4d2e1f05d 82
sam_grove 0:a977d0a3d81e 83 va_list arg;
sam_grove 0:a977d0a3d81e 84 va_start(arg, format);
sam_grove 0:a977d0a3d81e 85 r = vsprintf(buf, format, arg);
sam_grove 0:a977d0a3d81e 86 // this may not hit the heap but should alert the user anyways
sam_grove 4:2ba4d2e1f05d 87 if(r > sizeof(buf)) {
sam_grove 4:2ba4d2e1f05d 88 error("%s %d buffer overwrite!\n", __FILE__, __LINE__);
sam_grove 0:a977d0a3d81e 89 }
sam_grove 4:2ba4d2e1f05d 90 va_end(arg);
sam_grove 2:7e8a450a9101 91 r = BufferedSerial::write(buf, r);
sam_grove 4:2ba4d2e1f05d 92
sam_grove 0:a977d0a3d81e 93 return r;
sam_grove 0:a977d0a3d81e 94 }
sam_grove 0:a977d0a3d81e 95
sam_grove 2:7e8a450a9101 96 ssize_t BufferedSerial::write(const void *s, size_t length)
sam_grove 2:7e8a450a9101 97 {
sam_grove 2:7e8a450a9101 98 const char* ptr = (const char*)s;
sam_grove 2:7e8a450a9101 99 const char* end = ptr + length;
sam_grove 4:2ba4d2e1f05d 100
sam_grove 4:2ba4d2e1f05d 101 while (ptr != end) {
sam_grove 2:7e8a450a9101 102 _txbuf = *(ptr++);
sam_grove 2:7e8a450a9101 103 }
sam_grove 2:7e8a450a9101 104 BufferedSerial::prime();
sam_grove 4:2ba4d2e1f05d 105
sam_grove 4:2ba4d2e1f05d 106 return ptr - (const char*)s;
sam_grove 2:7e8a450a9101 107 }
sam_grove 2:7e8a450a9101 108
sam_grove 2:7e8a450a9101 109
sam_grove 0:a977d0a3d81e 110 void BufferedSerial::rxIrq(void)
sam_grove 0:a977d0a3d81e 111 {
sam_grove 3:6b76fcf27545 112 // read from the peripheral and make sure something is available
sam_grove 4:2ba4d2e1f05d 113 if(serial_readable(&_serial)) {
sam_grove 0:a977d0a3d81e 114 _rxbuf = serial_getc(&_serial); // if so load them into a buffer
sam_grove 0:a977d0a3d81e 115 }
sam_grove 4:2ba4d2e1f05d 116
sam_grove 0:a977d0a3d81e 117 return;
sam_grove 0:a977d0a3d81e 118 }
sam_grove 0:a977d0a3d81e 119
sam_grove 0:a977d0a3d81e 120 void BufferedSerial::txIrq(void)
sam_grove 0:a977d0a3d81e 121 {
sam_grove 3:6b76fcf27545 122 // see if there is room in the hardware fifo and if something is in the software fifo
sam_grove 4:2ba4d2e1f05d 123 while(serial_writable(&_serial)) {
sam_grove 4:2ba4d2e1f05d 124 if(_txbuf.available()) {
sam_grove 4:2ba4d2e1f05d 125 serial_putc(&_serial, (int)_txbuf.get());
sam_grove 4:2ba4d2e1f05d 126 } else {
sam_grove 4:2ba4d2e1f05d 127 // disable the TX interrupt when there is nothing left to send
ansond 6:8287e83943f0 128 SERIAL_BASE::attach(NULL, SERIAL_BASE::TxIrq);
sam_grove 4:2ba4d2e1f05d 129 break;
sam_grove 4:2ba4d2e1f05d 130 }
sam_grove 0:a977d0a3d81e 131 }
sam_grove 4:2ba4d2e1f05d 132
sam_grove 0:a977d0a3d81e 133 return;
sam_grove 0:a977d0a3d81e 134 }
sam_grove 0:a977d0a3d81e 135
sam_grove 1:57a11fb5d529 136 void BufferedSerial::prime(void)
sam_grove 1:57a11fb5d529 137 {
sam_grove 2:7e8a450a9101 138 // if already busy then the irq will pick this up
sam_grove 4:2ba4d2e1f05d 139 if(serial_writable(&_serial)) {
ansond 6:8287e83943f0 140 SERIAL_BASE::attach(NULL, SERIAL_BASE::TxIrq); // make sure not to cause contention in the irq
sam_grove 3:6b76fcf27545 141 BufferedSerial::txIrq(); // only write to hardware in one place
ansond 6:8287e83943f0 142 SERIAL_BASE::attach(this, &BufferedSerial::txIrq, SERIAL_BASE::TxIrq);
sam_grove 2:7e8a450a9101 143 }
sam_grove 4:2ba4d2e1f05d 144
sam_grove 1:57a11fb5d529 145 return;
sam_grove 1:57a11fb5d529 146 }
sam_grove 0:a977d0a3d81e 147
sam_grove 0:a977d0a3d81e 148