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Arduino/hardware/arduino/avr/libraries/SoftwareSerial/SoftwareSerial.h
Matthijs Kooijman f3aa5f23c4 Fix race condition in SoftwareSerial::overflow()
If an interrupt causing overflow would occur between reading
_buffer_overflow and clearing it, this overflow condition would be
immediately cleared and never be returned by overflow().

By only clearing the overflow flag if an overflow actually occurred,
this problem goes away (worst case overflow() returns false even though
an overflow _just_ occurred, but then the next call to overflow() will
return true).
2015-01-26 17:03:25 +01:00

115 lines
3.5 KiB
C++

/*
SoftwareSerial.h (formerly NewSoftSerial.h) -
Multi-instance software serial library for Arduino/Wiring
-- Interrupt-driven receive and other improvements by ladyada
(http://ladyada.net)
-- Tuning, circular buffer, derivation from class Print/Stream,
multi-instance support, porting to 8MHz processors,
various optimizations, PROGMEM delay tables, inverse logic and
direct port writing by Mikal Hart (http://www.arduiniana.org)
-- Pin change interrupt macros by Paul Stoffregen (http://www.pjrc.com)
-- 20MHz processor support by Garrett Mace (http://www.macetech.com)
-- ATmega1280/2560 support by Brett Hagman (http://www.roguerobotics.com/)
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
The latest version of this library can always be found at
http://arduiniana.org.
*/
#ifndef SoftwareSerial_h
#define SoftwareSerial_h
#include <inttypes.h>
#include <Stream.h>
/******************************************************************************
* Definitions
******************************************************************************/
#define _SS_MAX_RX_BUFF 64 // RX buffer size
#ifndef GCC_VERSION
#define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
#endif
class SoftwareSerial : public Stream
{
private:
// per object data
uint8_t _receivePin;
uint8_t _receiveBitMask;
volatile uint8_t *_receivePortRegister;
uint8_t _transmitBitMask;
volatile uint8_t *_transmitPortRegister;
uint16_t _rx_delay_centering;
uint16_t _rx_delay_intrabit;
uint16_t _rx_delay_stopbit;
uint16_t _tx_delay;
uint16_t _buffer_overflow:1;
uint16_t _inverse_logic:1;
// static data
static char _receive_buffer[_SS_MAX_RX_BUFF];
static volatile uint8_t _receive_buffer_tail;
static volatile uint8_t _receive_buffer_head;
static SoftwareSerial *active_object;
// private methods
void recv();
uint8_t rx_pin_read();
void tx_pin_write(uint8_t pin_state);
void setTX(uint8_t transmitPin);
void setRX(uint8_t receivePin);
void setRxIntMsk(bool enable);
// private static method for timing
static inline void tunedDelay(uint16_t delay);
public:
// public methods
SoftwareSerial(uint8_t receivePin, uint8_t transmitPin, bool inverse_logic = false);
~SoftwareSerial();
void begin(long speed);
bool listen();
void end();
bool isListening() { return this == active_object; }
bool stopListening();
bool overflow() { bool ret = _buffer_overflow; if (ret) _buffer_overflow = false; return ret; }
int peek();
virtual size_t write(uint8_t byte);
virtual int read();
virtual int available();
virtual void flush();
using Print::write;
// public only for easy access by interrupt handlers
static inline void handle_interrupt();
};
// Arduino 0012 workaround
#undef int
#undef char
#undef long
#undef byte
#undef float
#undef abs
#undef round
#endif