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
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Diff: BufferedSerial.cpp
- Revision:
- 0:a977d0a3d81e
- Child:
- 1:57a11fb5d529
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/BufferedSerial.cpp Thu May 23 19:31:30 2013 +0000 @@ -0,0 +1,122 @@ +/** + * @file BufferedSerial.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 "BufferedSerial.h" +#include "LogUtil.h" +#include <stdarg.h> + +BufferedSerial::BufferedSerial(PinName tx, PinName rx, const char* name) + : Serial(tx, rx, name) +{ + Serial::attach(this, &BufferedSerial::rxIrq, Serial::RxIrq); + Serial::attach(this, &BufferedSerial::txIrq, Serial::TxIrq); + + return; +} + +BufferedSerial::~BufferedSerial(void) +{ + Serial::attach(NULL, Serial::RxIrq); + Serial::attach(NULL, Serial::TxIrq); + + return; +} + +int BufferedSerial::readable(void) +{ + return _rxbuf.available(); // note: look if things are in the buffer +} + +int BufferedSerial::writeable(void) +{ + return 1; // buffer allows overwriting by design, always true +} + +int BufferedSerial::getc(void) +{ + return _rxbuf; // note: pulling from the buffer +} + +int BufferedSerial::putc(int c) +{ + _txbuf = (char)c; + BufferedSerial::txIrq(); // prime the txirq to stoke transmit + + return c; +} + +int BufferedSerial::puts(const char *s) +{ + const char *size = s; + + while(*(s) != 0) + { + _txbuf = *(s++); + } + BufferedSerial::txIrq(); // prime the txirq to stoke transmit + + return s - size; +} + +int BufferedSerial::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("Buffer Overwrite Occured!\n"); + } + r = BufferedSerial::puts(buf); + va_end(arg); + + return r; +} + +void BufferedSerial::rxIrq(void) +{ + // read from the peripheral and see if things are available + while(serial_readable(&_serial)) + { + _rxbuf = serial_getc(&_serial); // if so load them into a buffer + } + + return; +} + +void BufferedSerial::txIrq(void) +{ + // see if there is room in the hardware buffer and something is in the software buffer + while(serial_writable(&_serial) && _txbuf.available()) + { + serial_putc(&_serial, (int)_txbuf.get()); + } + + return; +} + + +