BufferedSoftSerials
Dependencies: Buffer SoftSerial1
Fork of BufferedSoftSerial by
Diff: BufferedSoftSerial.cpp
- Revision:
- 6:4e3e18b41ea6
- Child:
- 9:5b069a1896f9
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/BufferedSoftSerial.cpp Sat Apr 26 20:55:42 2014 +0000 @@ -0,0 +1,148 @@ +/** + * @file BufferedSoftSerial.cpp + * @brief Software Buffer - Extends mbed Serial functionallity adding irq driven TX and RX + * @author sam grove + * @version 1.0 + * @see + * + * Copyright (c) 2013 + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "BufferedSoftSerial.h" +#include <stdarg.h> + +BufferedSoftSerial::BufferedSoftSerial(PinName tx, PinName rx, const char* name) + : SoftSerial(tx, rx, name) +{ + SoftSerial::attach(this, &BufferedSoftSerial::rxIrq, SoftSerial::RxIrq); + + return; +} + +BufferedSoftSerial::~BufferedSoftSerial(void) +{ + SoftSerial::attach(NULL, SoftSerial::RxIrq); + SoftSerial::attach(NULL, SoftSerial::TxIrq); + + return; +} + +int BufferedSoftSerial::readable(void) +{ + return _rxbuf.available(); // note: look if things are in the buffer +} + +int BufferedSoftSerial::writeable(void) +{ + return 1; // buffer allows overwriting by design, always true +} + +int BufferedSoftSerial::getc(void) +{ + return _rxbuf; +} + +int BufferedSoftSerial::putc(int c) +{ + _txbuf = (char)c; + BufferedSoftSerial::prime(); + + return c; +} + +int BufferedSoftSerial::puts(const char *s) +{ + const char* ptr = s; + + while(*(ptr) != 0) { + _txbuf = *(ptr++); + } + _txbuf = '\n'; // done per puts definition + BufferedSoftSerial::prime(); + + return (ptr - s) + 1; +} + +int BufferedSoftSerial::printf(const char* format, ...) +{ + char buf[256] = {0}; + int r = 0; + + va_list arg; + va_start(arg, format); + r = vsprintf(buf, format, arg); + // this may not hit the heap but should alert the user anyways + if(r > sizeof(buf)) { + error("%s %d buffer overwrite!\n", __FILE__, __LINE__); + } + va_end(arg); + r = BufferedSoftSerial::write(buf, r); + + return r; +} + +ssize_t BufferedSoftSerial::write(const void *s, size_t length) +{ + const char* ptr = (const char*)s; + const char* end = ptr + length; + + while (ptr != end) { + _txbuf = *(ptr++); + } + BufferedSoftSerial::prime(); + + return ptr - (const char*)s; +} + + +void BufferedSoftSerial::rxIrq(void) +{ + // read from the peripheral and make sure something is available + if(SoftSerial::readable()) { + _rxbuf = _getc(); // if so load them into a buffer + } + + return; +} + +void BufferedSoftSerial::txIrq(void) +{ + // see if there is room in the hardware fifo and if something is in the software fifo + while(SoftSerial::writeable()) { + if(_txbuf.available()) { + _putc((int)_txbuf.get()); + } else { + // disable the TX interrupt when there is nothing left to send + SoftSerial::attach(NULL, SoftSerial::TxIrq); + break; + } + } + + return; +} + +void BufferedSoftSerial::prime(void) +{ + // if already busy then the irq will pick this up + if(SoftSerial::writeable()) { + SoftSerial::attach(NULL, SoftSerial::TxIrq); // make sure not to cause contention in the irq + BufferedSoftSerial::txIrq(); // only write to hardware in one place + SoftSerial::attach(this, &BufferedSoftSerial::txIrq, SoftSerial::TxIrq); + } + + return; +} + +