Sam Grove / 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

Dependents:   buffered_serial_test BLE_Police_HRM evena_BLE_Police_HRM df-2014-workshop-rfid-case-generator-k64f ... more

Example

 #include "mbed.h"
 #include "BufferedSerial.h"

 BufferedSerial pc(USBTX, USBRX);

 int main()
 {
     pc.baud(115200);
   
     while(1)
     {
         Timer s;
       
         s.start();
         pc.printf("Hello World - buff\n");
         int buffered_time = s.read_us();
         wait(0.1f); // give time for the buffer to empty
       
         s.reset();
         printf("Hello World - poll\n");
         int polled_time = s.read_us();
         s.stop();
         wait(0.1f); // give time for the buffer to empty
       
         pc.printf("printf buffered took %d us\n", buffered_time);
         pc.printf("printf polled took %d us\n", polled_time);
         wait(0.5f);
     }
 }

BufferedSerial.cpp@11:779304f9c5d2, 2015-07-26 (annotated)

Committer:
sam_grove
Date:
Sun Jul 26 21:53:11 2015 +0000
Revision:
11:779304f9c5d2
Parent:
10:9ee15ae3d1a3
Child:
13:c17c532bc4f8
Force use of RawSerial

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
ansond 10:9ee15ae3d1a3 26 BufferedSerial::BufferedSerial(PinName tx, PinName rx, uint32_t buf_size, uint32_t tx_multiple, const char* name)
sam_grove 11:779304f9c5d2 27 : RawSerial(tx, rx) , _rxbuf(buf_size), _txbuf((uint32_t)(tx_multiple*buf_size))
sam_grove 0:a977d0a3d81e 28 {
sam_grove 11:779304f9c5d2 29 RawSerial::attach(this, &BufferedSerial::rxIrq, Serial::RxIrq);
ansond 10:9ee15ae3d1a3 30 this->_buf_size = buf_size;
ansond 10:9ee15ae3d1a3 31 this->_tx_multiple = tx_multiple;
sam_grove 0:a977d0a3d81e 32 return;
sam_grove 0:a977d0a3d81e 33 }
sam_grove 0:a977d0a3d81e 34
sam_grove 0:a977d0a3d81e 35 BufferedSerial::~BufferedSerial(void)
sam_grove 0:a977d0a3d81e 36 {
sam_grove 11:779304f9c5d2 37 RawSerial::attach(NULL, RawSerial::RxIrq);
sam_grove 11:779304f9c5d2 38 RawSerial::attach(NULL, RawSerial::TxIrq);
sam_grove 4:2ba4d2e1f05d 39
sam_grove 0:a977d0a3d81e 40 return;
sam_grove 0:a977d0a3d81e 41 }
sam_grove 0:a977d0a3d81e 42
sam_grove 0:a977d0a3d81e 43 int BufferedSerial::readable(void)
sam_grove 0:a977d0a3d81e 44 {
sam_grove 0:a977d0a3d81e 45 return _rxbuf.available(); // note: look if things are in the buffer
sam_grove 0:a977d0a3d81e 46 }
sam_grove 0:a977d0a3d81e 47
sam_grove 0:a977d0a3d81e 48 int BufferedSerial::writeable(void)
sam_grove 0:a977d0a3d81e 49 {
sam_grove 0:a977d0a3d81e 50 return 1; // buffer allows overwriting by design, always true
sam_grove 0:a977d0a3d81e 51 }
sam_grove 0:a977d0a3d81e 52
sam_grove 0:a977d0a3d81e 53 int BufferedSerial::getc(void)
sam_grove 0:a977d0a3d81e 54 {
sam_grove 3:6b76fcf27545 55 return _rxbuf;
sam_grove 0:a977d0a3d81e 56 }
sam_grove 0:a977d0a3d81e 57
sam_grove 0:a977d0a3d81e 58 int BufferedSerial::putc(int c)
sam_grove 0:a977d0a3d81e 59 {
sam_grove 0:a977d0a3d81e 60 _txbuf = (char)c;
sam_grove 1:57a11fb5d529 61 BufferedSerial::prime();
sam_grove 4:2ba4d2e1f05d 62
sam_grove 0:a977d0a3d81e 63 return c;
sam_grove 0:a977d0a3d81e 64 }
sam_grove 0:a977d0a3d81e 65
sam_grove 0:a977d0a3d81e 66 int BufferedSerial::puts(const char *s)
sam_grove 0:a977d0a3d81e 67 {
ansond 7:6fa214b41d73 68 if (s != NULL) {
ansond 7:6fa214b41d73 69 const char* ptr = s;
ansond 7:6fa214b41d73 70
ansond 7:6fa214b41d73 71 while(*(ptr) != 0) {
ansond 7:6fa214b41d73 72 _txbuf = *(ptr++);
ansond 7:6fa214b41d73 73 }
ansond 7:6fa214b41d73 74 _txbuf = '\n'; // done per puts definition
ansond 7:6fa214b41d73 75 BufferedSerial::prime();
ansond 7:6fa214b41d73 76
ansond 7:6fa214b41d73 77 return (ptr - s) + 1;
sam_grove 0:a977d0a3d81e 78 }
ansond 7:6fa214b41d73 79 return 0;
sam_grove 0:a977d0a3d81e 80 }
sam_grove 0:a977d0a3d81e 81
sam_grove 0:a977d0a3d81e 82 int BufferedSerial::printf(const char* format, ...)
sam_grove 0:a977d0a3d81e 83 {
ansond 10:9ee15ae3d1a3 84 char buffer[this->_buf_size];
ansond 10:9ee15ae3d1a3 85 memset(buffer,0,this->_buf_size);
sam_grove 0:a977d0a3d81e 86 int r = 0;
sam_grove 4:2ba4d2e1f05d 87
sam_grove 0:a977d0a3d81e 88 va_list arg;
sam_grove 0:a977d0a3d81e 89 va_start(arg, format);
ansond 10:9ee15ae3d1a3 90 r = vsprintf(buffer, format, arg);
sam_grove 0:a977d0a3d81e 91 // this may not hit the heap but should alert the user anyways
ansond 10:9ee15ae3d1a3 92 if(r > this->_buf_size) {
ansond 10:9ee15ae3d1a3 93 error("%s %d buffer overwrite (max_buf_size: %d exceeded: %d)!\r\n", __FILE__, __LINE__,this->_buf_size,r);
ansond 7:6fa214b41d73 94 va_end(arg);
ansond 7:6fa214b41d73 95 return 0;
sam_grove 0:a977d0a3d81e 96 }
sam_grove 4:2ba4d2e1f05d 97 va_end(arg);
ansond 10:9ee15ae3d1a3 98 r = BufferedSerial::write(buffer, r);
sam_grove 4:2ba4d2e1f05d 99
sam_grove 0:a977d0a3d81e 100 return r;
sam_grove 0:a977d0a3d81e 101 }
sam_grove 0:a977d0a3d81e 102
sam_grove 2:7e8a450a9101 103 ssize_t BufferedSerial::write(const void *s, size_t length)
sam_grove 2:7e8a450a9101 104 {
ansond 7:6fa214b41d73 105 if (s != NULL && length > 0) {
ansond 7:6fa214b41d73 106 const char* ptr = (const char*)s;
ansond 7:6fa214b41d73 107 const char* end = ptr + length;
ansond 7:6fa214b41d73 108
ansond 7:6fa214b41d73 109 while (ptr != end) {
ansond 7:6fa214b41d73 110 _txbuf = *(ptr++);
ansond 7:6fa214b41d73 111 }
ansond 7:6fa214b41d73 112 BufferedSerial::prime();
ansond 7:6fa214b41d73 113
ansond 7:6fa214b41d73 114 return ptr - (const char*)s;
sam_grove 2:7e8a450a9101 115 }
ansond 7:6fa214b41d73 116 return 0;
sam_grove 2:7e8a450a9101 117 }
sam_grove 2:7e8a450a9101 118
sam_grove 2:7e8a450a9101 119
sam_grove 0:a977d0a3d81e 120 void BufferedSerial::rxIrq(void)
sam_grove 0:a977d0a3d81e 121 {
sam_grove 3:6b76fcf27545 122 // read from the peripheral and make sure something is available
sam_grove 4:2ba4d2e1f05d 123 if(serial_readable(&_serial)) {
sam_grove 0:a977d0a3d81e 124 _rxbuf = serial_getc(&_serial); // if so load them into a buffer
sam_grove 0:a977d0a3d81e 125 }
sam_grove 4:2ba4d2e1f05d 126
sam_grove 0:a977d0a3d81e 127 return;
sam_grove 0:a977d0a3d81e 128 }
sam_grove 0:a977d0a3d81e 129
sam_grove 0:a977d0a3d81e 130 void BufferedSerial::txIrq(void)
sam_grove 0:a977d0a3d81e 131 {
sam_grove 3:6b76fcf27545 132 // see if there is room in the hardware fifo and if something is in the software fifo
sam_grove 4:2ba4d2e1f05d 133 while(serial_writable(&_serial)) {
sam_grove 4:2ba4d2e1f05d 134 if(_txbuf.available()) {
sam_grove 4:2ba4d2e1f05d 135 serial_putc(&_serial, (int)_txbuf.get());
sam_grove 4:2ba4d2e1f05d 136 } else {
sam_grove 4:2ba4d2e1f05d 137 // disable the TX interrupt when there is nothing left to send
sam_grove 11:779304f9c5d2 138 RawSerial::attach(NULL, RawSerial::TxIrq);
sam_grove 4:2ba4d2e1f05d 139 break;
sam_grove 4:2ba4d2e1f05d 140 }
sam_grove 0:a977d0a3d81e 141 }
sam_grove 4:2ba4d2e1f05d 142
sam_grove 0:a977d0a3d81e 143 return;
sam_grove 0:a977d0a3d81e 144 }
sam_grove 0:a977d0a3d81e 145
sam_grove 1:57a11fb5d529 146 void BufferedSerial::prime(void)
sam_grove 1:57a11fb5d529 147 {
sam_grove 2:7e8a450a9101 148 // if already busy then the irq will pick this up
sam_grove 4:2ba4d2e1f05d 149 if(serial_writable(&_serial)) {
sam_grove 11:779304f9c5d2 150 RawSerial::attach(NULL, RawSerial::TxIrq); // make sure not to cause contention in the irq
sam_grove 3:6b76fcf27545 151 BufferedSerial::txIrq(); // only write to hardware in one place
sam_grove 11:779304f9c5d2 152 RawSerial::attach(this, &BufferedSerial::txIrq, RawSerial::TxIrq);
sam_grove 2:7e8a450a9101 153 }
sam_grove 4:2ba4d2e1f05d 154
sam_grove 1:57a11fb5d529 155 return;
sam_grove 1:57a11fb5d529 156 }
sam_grove 0:a977d0a3d81e 157
sam_grove 0:a977d0a3d81e 158