Garrett LoVerde / 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@3:6b76fcf27545, 2013-06-12 (annotated)

Committer:
sam_grove
Date:
Wed Jun 12 20:40:15 2013 +0000
Revision:
3:6b76fcf27545
Parent:
2:7e8a450a9101
Child:
4:2ba4d2e1f05d
Updates to block only tx irq when fifo needs a kick. Updated comments and documentation

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 0:a977d0a3d81e 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 "LogUtil.h"
sam_grove 0:a977d0a3d81e 25 #include <stdarg.h>
sam_grove 0:a977d0a3d81e 26
sam_grove 0:a977d0a3d81e 27 BufferedSerial::BufferedSerial(PinName tx, PinName rx, const char* name)
sam_grove 0:a977d0a3d81e 28 : Serial(tx, rx, name)
sam_grove 0:a977d0a3d81e 29 {
sam_grove 0:a977d0a3d81e 30 Serial::attach(this, &BufferedSerial::rxIrq, Serial::RxIrq);
sam_grove 0:a977d0a3d81e 31 Serial::attach(this, &BufferedSerial::txIrq, Serial::TxIrq);
sam_grove 0:a977d0a3d81e 32
sam_grove 0:a977d0a3d81e 33 return;
sam_grove 0:a977d0a3d81e 34 }
sam_grove 0:a977d0a3d81e 35
sam_grove 0:a977d0a3d81e 36 BufferedSerial::~BufferedSerial(void)
sam_grove 0:a977d0a3d81e 37 {
sam_grove 0:a977d0a3d81e 38 Serial::attach(NULL, Serial::RxIrq);
sam_grove 0:a977d0a3d81e 39 Serial::attach(NULL, Serial::TxIrq);
sam_grove 0:a977d0a3d81e 40
sam_grove 0:a977d0a3d81e 41 return;
sam_grove 0:a977d0a3d81e 42 }
sam_grove 0:a977d0a3d81e 43
sam_grove 0:a977d0a3d81e 44 int BufferedSerial::readable(void)
sam_grove 0:a977d0a3d81e 45 {
sam_grove 0:a977d0a3d81e 46 return _rxbuf.available(); // note: look if things are in the buffer
sam_grove 0:a977d0a3d81e 47 }
sam_grove 0:a977d0a3d81e 48
sam_grove 0:a977d0a3d81e 49 int BufferedSerial::writeable(void)
sam_grove 0:a977d0a3d81e 50 {
sam_grove 0:a977d0a3d81e 51 return 1; // buffer allows overwriting by design, always true
sam_grove 0:a977d0a3d81e 52 }
sam_grove 0:a977d0a3d81e 53
sam_grove 0:a977d0a3d81e 54 int BufferedSerial::getc(void)
sam_grove 0:a977d0a3d81e 55 {
sam_grove 3:6b76fcf27545 56 return _rxbuf;
sam_grove 0:a977d0a3d81e 57 }
sam_grove 0:a977d0a3d81e 58
sam_grove 0:a977d0a3d81e 59 int BufferedSerial::putc(int c)
sam_grove 0:a977d0a3d81e 60 {
sam_grove 0:a977d0a3d81e 61 _txbuf = (char)c;
sam_grove 1:57a11fb5d529 62 BufferedSerial::prime();
sam_grove 0:a977d0a3d81e 63
sam_grove 0:a977d0a3d81e 64 return c;
sam_grove 0:a977d0a3d81e 65 }
sam_grove 0:a977d0a3d81e 66
sam_grove 0:a977d0a3d81e 67 int BufferedSerial::puts(const char *s)
sam_grove 0:a977d0a3d81e 68 {
sam_grove 2:7e8a450a9101 69 const char* ptr = s;
sam_grove 0:a977d0a3d81e 70
sam_grove 2:7e8a450a9101 71 while(*(ptr) != 0)
sam_grove 0:a977d0a3d81e 72 {
sam_grove 2:7e8a450a9101 73 _txbuf = *(ptr++);
sam_grove 0:a977d0a3d81e 74 }
sam_grove 2:7e8a450a9101 75 _txbuf = '\n'; // done per puts definition
sam_grove 1:57a11fb5d529 76 BufferedSerial::prime();
sam_grove 0:a977d0a3d81e 77
sam_grove 2:7e8a450a9101 78 return (ptr - s) + 1;
sam_grove 0:a977d0a3d81e 79 }
sam_grove 0:a977d0a3d81e 80
sam_grove 0:a977d0a3d81e 81 int BufferedSerial::printf(const char* format, ...)
sam_grove 0:a977d0a3d81e 82 {
sam_grove 0:a977d0a3d81e 83 char buf[256] = {0};
sam_grove 0:a977d0a3d81e 84 int r = 0;
sam_grove 0:a977d0a3d81e 85
sam_grove 0:a977d0a3d81e 86 va_list arg;
sam_grove 0:a977d0a3d81e 87 va_start(arg, format);
sam_grove 0:a977d0a3d81e 88 r = vsprintf(buf, format, arg);
sam_grove 0:a977d0a3d81e 89 // this may not hit the heap but should alert the user anyways
sam_grove 0:a977d0a3d81e 90 if(r > sizeof(buf))
sam_grove 0:a977d0a3d81e 91 {
sam_grove 2:7e8a450a9101 92 ERROR("Buffer Overflow on the Stack Occured!\n");
sam_grove 0:a977d0a3d81e 93 }
sam_grove 2:7e8a450a9101 94 r = BufferedSerial::write(buf, r);
sam_grove 0:a977d0a3d81e 95 va_end(arg);
sam_grove 0:a977d0a3d81e 96
sam_grove 0:a977d0a3d81e 97 return r;
sam_grove 0:a977d0a3d81e 98 }
sam_grove 0:a977d0a3d81e 99
sam_grove 2:7e8a450a9101 100 ssize_t BufferedSerial::write(const void *s, size_t length)
sam_grove 2:7e8a450a9101 101 {
sam_grove 2:7e8a450a9101 102 const char* ptr = (const char*)s;
sam_grove 2:7e8a450a9101 103 const char* end = ptr + length;
sam_grove 2:7e8a450a9101 104
sam_grove 2:7e8a450a9101 105 while (ptr != end)
sam_grove 2:7e8a450a9101 106 {
sam_grove 2:7e8a450a9101 107 _txbuf = *(ptr++);
sam_grove 2:7e8a450a9101 108 }
sam_grove 2:7e8a450a9101 109 BufferedSerial::prime();
sam_grove 2:7e8a450a9101 110
sam_grove 2:7e8a450a9101 111 return ptr - (const char*)s;
sam_grove 2:7e8a450a9101 112 }
sam_grove 2:7e8a450a9101 113
sam_grove 2:7e8a450a9101 114
sam_grove 0:a977d0a3d81e 115 void BufferedSerial::rxIrq(void)
sam_grove 0:a977d0a3d81e 116 {
sam_grove 3:6b76fcf27545 117 // read from the peripheral and make sure something is available
sam_grove 2:7e8a450a9101 118 if(serial_readable(&_serial))
sam_grove 0:a977d0a3d81e 119 {
sam_grove 0:a977d0a3d81e 120 _rxbuf = serial_getc(&_serial); // if so load them into a buffer
sam_grove 0:a977d0a3d81e 121 }
sam_grove 0:a977d0a3d81e 122
sam_grove 0:a977d0a3d81e 123 return;
sam_grove 0:a977d0a3d81e 124 }
sam_grove 0:a977d0a3d81e 125
sam_grove 0:a977d0a3d81e 126 void BufferedSerial::txIrq(void)
sam_grove 0:a977d0a3d81e 127 {
sam_grove 3:6b76fcf27545 128 // see if there is room in the hardware fifo and if something is in the software fifo
sam_grove 3:6b76fcf27545 129 while(serial_writable(&_serial) && _txbuf.available())
sam_grove 0:a977d0a3d81e 130 {
sam_grove 0:a977d0a3d81e 131 serial_putc(&_serial, (int)_txbuf.get());
sam_grove 0:a977d0a3d81e 132 }
sam_grove 0:a977d0a3d81e 133
sam_grove 0:a977d0a3d81e 134 return;
sam_grove 0:a977d0a3d81e 135 }
sam_grove 0:a977d0a3d81e 136
sam_grove 1:57a11fb5d529 137 void BufferedSerial::prime(void)
sam_grove 1:57a11fb5d529 138 {
sam_grove 2:7e8a450a9101 139 // if already busy then the irq will pick this up
sam_grove 2:7e8a450a9101 140 if(serial_writable(&_serial))
sam_grove 2:7e8a450a9101 141 {
sam_grove 3:6b76fcf27545 142 Serial::attach(NULL, Serial::TxIrq); // make sure not to cause contention in the irq
sam_grove 3:6b76fcf27545 143 BufferedSerial::txIrq(); // only write to hardware in one place
sam_grove 3:6b76fcf27545 144 Serial::attach(this, &BufferedSerial::txIrq, Serial::TxIrq);
sam_grove 2:7e8a450a9101 145 }
sam_grove 1:57a11fb5d529 146
sam_grove 1:57a11fb5d529 147 return;
sam_grove 1:57a11fb5d529 148 }
sam_grove 0:a977d0a3d81e 149
sam_grove 0:a977d0a3d81e 150