diff options
| author | Thibaut VIARD <thibaut.viard@atmel.com> | 2011-06-21 00:20:43 +0200 |
|---|---|---|
| committer | Thibaut VIARD <thibaut.viard@atmel.com> | 2011-06-21 00:20:43 +0200 |
| commit | 0887b98f627500271b5ad8b3c4f6c7b90bc227ee (patch) | |
| tree | ef8626954567ba22e392c68c8f3606416b07b5b5 /libraries/SoftwareSerial/SoftwareSerial.cpp | |
| parent | 90c487402cefadb6a2aab907ab07075cbb759e34 (diff) | |
Moving all AVR specific libraries to hardware/avr
Diffstat (limited to 'libraries/SoftwareSerial/SoftwareSerial.cpp')
| -rwxr-xr-x | libraries/SoftwareSerial/SoftwareSerial.cpp | 512 |
1 files changed, 512 insertions, 0 deletions
diff --git a/libraries/SoftwareSerial/SoftwareSerial.cpp b/libraries/SoftwareSerial/SoftwareSerial.cpp new file mode 100755 index 0000000..b8a1fc4 --- /dev/null +++ b/libraries/SoftwareSerial/SoftwareSerial.cpp @@ -0,0 +1,512 @@ +/*
+SoftwareSerial.cpp (formerly NewSoftSerial.cpp) -
+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.
+*/
+
+// When set, _DEBUG co-opts pins 11 and 13 for debugging with an
+// oscilloscope or logic analyzer. Beware: it also slightly modifies
+// the bit times, so don't rely on it too much at high baud rates
+#define _DEBUG 0
+#define _DEBUG_PIN1 11
+#define _DEBUG_PIN2 13
+//
+// Includes
+//
+#include <avr/interrupt.h>
+#include <avr/pgmspace.h>
+#include "Arduino.h"
+#include "SoftwareSerial.h"
+#include "icrmacros.h"
+//
+// Lookup table
+//
+typedef struct _DELAY_TABLE
+{
+ long baud;
+ unsigned short rx_delay_centering;
+ unsigned short rx_delay_intrabit;
+ unsigned short rx_delay_stopbit;
+ unsigned short tx_delay;
+} DELAY_TABLE;
+
+#if F_CPU == 16000000
+
+static const DELAY_TABLE PROGMEM table[] =
+{
+ // baud rxcenter rxintra rxstop tx
+ { 115200, 1, 17, 17, 12, },
+ { 57600, 10, 37, 37, 33, },
+ { 38400, 25, 57, 57, 54, },
+ { 31250, 31, 70, 70, 68, },
+ { 28800, 34, 77, 77, 74, },
+ { 19200, 54, 117, 117, 114, },
+ { 14400, 74, 156, 156, 153, },
+ { 9600, 114, 236, 236, 233, },
+ { 4800, 233, 474, 474, 471, },
+ { 2400, 471, 950, 950, 947, },
+ { 1200, 947, 1902, 1902, 1899, },
+ { 300, 3804, 7617, 7617, 7614, },
+};
+
+const int XMIT_START_ADJUSTMENT = 5;
+
+#elif F_CPU == 8000000
+
+static const DELAY_TABLE table[] PROGMEM =
+{
+ // baud rxcenter rxintra rxstop tx
+ { 115200, 1, 5, 5, 3, },
+ { 57600, 1, 15, 15, 13, },
+ { 38400, 2, 25, 26, 23, },
+ { 31250, 7, 32, 33, 29, },
+ { 28800, 11, 35, 35, 32, },
+ { 19200, 20, 55, 55, 52, },
+ { 14400, 30, 75, 75, 72, },
+ { 9600, 50, 114, 114, 112, },
+ { 4800, 110, 233, 233, 230, },
+ { 2400, 229, 472, 472, 469, },
+ { 1200, 467, 948, 948, 945, },
+ { 300, 1895, 3805, 3805, 3802, },
+};
+
+const int XMIT_START_ADJUSTMENT = 4;
+
+#elif F_CPU == 20000000
+
+// 20MHz support courtesy of the good people at macegr.com.
+// Thanks, Garrett!
+
+static const DELAY_TABLE PROGMEM table[] =
+{
+ // baud rxcenter rxintra rxstop tx
+ { 115200, 3, 21, 21, 18, },
+ { 57600, 20, 43, 43, 41, },
+ { 38400, 37, 73, 73, 70, },
+ { 31250, 45, 89, 89, 88, },
+ { 28800, 46, 98, 98, 95, },
+ { 19200, 71, 148, 148, 145, },
+ { 14400, 96, 197, 197, 194, },
+ { 9600, 146, 297, 297, 294, },
+ { 4800, 296, 595, 595, 592, },
+ { 2400, 592, 1189, 1189, 1186, },
+ { 1200, 1187, 2379, 2379, 2376, },
+ { 300, 4759, 9523, 9523, 9520, },
+};
+
+const int XMIT_START_ADJUSTMENT = 6;
+
+#else
+
+#error This version of SoftwareSerial supports only 20, 16 and 8MHz processors
+
+#endif
+
+//
+// Statics
+//
+SoftwareSerial *SoftwareSerial::active_object = 0;
+char SoftwareSerial::_receive_buffer[_SS_MAX_RX_BUFF];
+volatile uint8_t SoftwareSerial::_receive_buffer_tail = 0;
+volatile uint8_t SoftwareSerial::_receive_buffer_head = 0;
+
+//
+// Debugging
+//
+// This function generates a brief pulse
+// for debugging or measuring on an oscilloscope.
+inline void DebugPulse(uint8_t pin, uint8_t count)
+{
+#if _DEBUG
+ volatile uint8_t *pport = portOutputRegister(digitalPinToPort(pin));
+
+ uint8_t val = *pport;
+ while (count--)
+ {
+ *pport = val | digitalPinToBitMask(pin);
+ *pport = val;
+ }
+#endif
+}
+
+//
+// Private methods
+//
+
+/* static */
+inline void SoftwareSerial::tunedDelay(uint16_t delay) {
+ uint8_t tmp=0;
+
+ asm volatile("sbiw %0, 0x01 \n\t"
+ "ldi %1, 0xFF \n\t"
+ "cpi %A0, 0xFF \n\t"
+ "cpc %B0, %1 \n\t"
+ "brne .-10 \n\t"
+ : "+r" (delay), "+a" (tmp)
+ : "0" (delay)
+ );
+}
+
+// This function sets the current object as the "listening"
+// one and returns true if it replaces another
+bool SoftwareSerial::listen()
+{
+ if (active_object != this)
+ {
+ _buffer_overflow = false;
+ uint8_t oldSREG = SREG;
+ cli();
+ _receive_buffer_head = _receive_buffer_tail = 0;
+ active_object = this;
+ SREG = oldSREG;
+ return true;
+ }
+
+ return false;
+}
+
+//
+// The receive routine called by the interrupt handler
+//
+void SoftwareSerial::recv()
+{
+
+#if GCC_VERSION < 40302
+// Work-around for avr-gcc 4.3.0 OSX version bug
+// Preserve the registers that the compiler misses
+// (courtesy of Arduino forum user *etracer*)
+ asm volatile(
+ "push r18 \n\t"
+ "push r19 \n\t"
+ "push r20 \n\t"
+ "push r21 \n\t"
+ "push r22 \n\t"
+ "push r23 \n\t"
+ "push r26 \n\t"
+ "push r27 \n\t"
+ ::);
+#endif
+
+ uint8_t d = 0;
+
+ // If RX line is high, then we don't see any start bit
+ // so interrupt is probably not for us
+ if (_inverse_logic ? rx_pin_read() : !rx_pin_read())
+ {
+ // Wait approximately 1/2 of a bit width to "center" the sample
+ tunedDelay(_rx_delay_centering);
+ DebugPulse(_DEBUG_PIN2, 1);
+
+ // Read each of the 8 bits
+ for (uint8_t i=0x1; i; i <<= 1)
+ {
+ tunedDelay(_rx_delay_intrabit);
+ DebugPulse(_DEBUG_PIN2, 1);
+ uint8_t noti = ~i;
+ if (rx_pin_read())
+ d |= i;
+ else // else clause added to ensure function timing is ~balanced
+ d &= noti;
+ }
+
+ // skip the stop bit
+ tunedDelay(_rx_delay_stopbit);
+ DebugPulse(_DEBUG_PIN2, 1);
+
+ if (_inverse_logic)
+ d = ~d;
+
+ // if buffer full, set the overflow flag and return
+ if ((_receive_buffer_tail + 1) % _SS_MAX_RX_BUFF != _receive_buffer_head)
+ {
+ // save new data in buffer: tail points to where byte goes
+ _receive_buffer[_receive_buffer_tail] = d; // save new byte
+ _receive_buffer_tail = (_receive_buffer_tail + 1) % _SS_MAX_RX_BUFF;
+ }
+ else
+ {
+#if _DEBUG // for scope: pulse pin as overflow indictator
+ DebugPulse(_DEBUG_PIN1, 1);
+#endif
+ _buffer_overflow = true;
+ }
+ }
+
+#if GCC_VERSION < 40302
+// Work-around for avr-gcc 4.3.0 OSX version bug
+// Restore the registers that the compiler misses
+ asm volatile(
+ "pop r27 \n\t"
+ "pop r26 \n\t"
+ "pop r23 \n\t"
+ "pop r22 \n\t"
+ "pop r21 \n\t"
+ "pop r20 \n\t"
+ "pop r19 \n\t"
+ "pop r18 \n\t"
+ ::);
+#endif
+}
+
+void SoftwareSerial::tx_pin_write(uint8_t pin_state)
+{
+ if (pin_state == LOW)
+ *_transmitPortRegister &= ~_transmitBitMask;
+ else
+ *_transmitPortRegister |= _transmitBitMask;
+}
+
+uint8_t SoftwareSerial::rx_pin_read()
+{
+ return *_receivePortRegister & _receiveBitMask;
+}
+
+//
+// Interrupt handling
+//
+
+/* static */
+inline void SoftwareSerial::handle_interrupt()
+{
+ if (active_object)
+ {
+ active_object->recv();
+ }
+}
+
+#if defined(PCINT0_vect)
+ISR(PCINT0_vect)
+{
+ SoftwareSerial::handle_interrupt();
+}
+#endif
+
+#if defined(PCINT1_vect)
+ISR(PCINT1_vect)
+{
+ SoftwareSerial::handle_interrupt();
+}
+#endif
+
+#if defined(PCINT2_vect)
+ISR(PCINT2_vect)
+{
+ SoftwareSerial::handle_interrupt();
+}
+#endif
+
+#if defined(PCINT3_vect)
+ISR(PCINT3_vect)
+{
+ SoftwareSerial::handle_interrupt();
+}
+#endif
+
+//
+// Constructor
+//
+SoftwareSerial::SoftwareSerial(uint8_t receivePin, uint8_t transmitPin, bool inverse_logic /* = false */) :
+ _rx_delay_centering(0),
+ _rx_delay_intrabit(0),
+ _rx_delay_stopbit(0),
+ _tx_delay(0),
+ _buffer_overflow(false),
+ _inverse_logic(inverse_logic)
+{
+ setTX(transmitPin);
+ setRX(receivePin);
+}
+
+//
+// Destructor
+//
+SoftwareSerial::~SoftwareSerial()
+{
+ end();
+}
+
+void SoftwareSerial::setTX(uint8_t tx)
+{
+ pinMode(tx, OUTPUT);
+ digitalWrite(tx, HIGH);
+ _transmitBitMask = digitalPinToBitMask(tx);
+ uint8_t port = digitalPinToPort(tx);
+ _transmitPortRegister = portOutputRegister(port);
+}
+
+void SoftwareSerial::setRX(uint8_t rx)
+{
+ pinMode(rx, INPUT);
+ if (!_inverse_logic)
+ digitalWrite(rx, HIGH); // pullup for normal logic!
+ _receivePin = rx;
+ _receiveBitMask = digitalPinToBitMask(rx);
+ uint8_t port = digitalPinToPort(rx);
+ _receivePortRegister = portInputRegister(port);
+}
+
+//
+// Public methods
+//
+
+void SoftwareSerial::begin(long speed)
+{
+ _rx_delay_centering = _rx_delay_intrabit = _rx_delay_stopbit = _tx_delay = 0;
+
+ for (unsigned i=0; i<sizeof(table)/sizeof(table[0]); ++i)
+ {
+ long baud = pgm_read_dword(&table[i].baud);
+ if (baud == speed)
+ {
+ _rx_delay_centering = pgm_read_word(&table[i].rx_delay_centering);
+ _rx_delay_intrabit = pgm_read_word(&table[i].rx_delay_intrabit);
+ _rx_delay_stopbit = pgm_read_word(&table[i].rx_delay_stopbit);
+ _tx_delay = pgm_read_word(&table[i].tx_delay);
+ break;
+ }
+ }
+
+ // Set up RX interrupts, but only if we have a valid RX baud rate
+ if (_rx_delay_stopbit)
+ {
+ if (digitalPinToPCICR(_receivePin))
+ {
+ *digitalPinToPCICR(_receivePin) |= _BV(digitalPinToPCICRbit(_receivePin));
+ *digitalPinToPCMSK(_receivePin) |= _BV(digitalPinToPCMSKbit(_receivePin));
+ }
+ tunedDelay(_tx_delay); // if we were low this establishes the end
+ }
+
+#if _DEBUG
+ pinMode(_DEBUG_PIN1, OUTPUT);
+ pinMode(_DEBUG_PIN2, OUTPUT);
+#endif
+
+ listen();
+}
+
+void SoftwareSerial::end()
+{
+ if (digitalPinToPCMSK(_receivePin))
+ *digitalPinToPCMSK(_receivePin) &= ~_BV(digitalPinToPCMSKbit(_receivePin));
+}
+
+
+// Read data from buffer
+int SoftwareSerial::read()
+{
+ if (!isListening())
+ return -1;
+
+ // Empty buffer?
+ if (_receive_buffer_head == _receive_buffer_tail)
+ return -1;
+
+ // Read from "head"
+ uint8_t d = _receive_buffer[_receive_buffer_head]; // grab next byte
+ _receive_buffer_head = (_receive_buffer_head + 1) % _SS_MAX_RX_BUFF;
+ return d;
+}
+
+int SoftwareSerial::available()
+{
+ if (!isListening())
+ return 0;
+
+ return (_receive_buffer_tail + _SS_MAX_RX_BUFF - _receive_buffer_head) % _SS_MAX_RX_BUFF;
+}
+
+void SoftwareSerial::write(uint8_t b)
+{
+ if (_tx_delay == 0)
+ return;
+
+ uint8_t oldSREG = SREG;
+ cli(); // turn off interrupts for a clean txmit
+
+ // Write the start bit
+ tx_pin_write(_inverse_logic ? HIGH : LOW);
+ tunedDelay(_tx_delay + XMIT_START_ADJUSTMENT);
+
+ // Write each of the 8 bits
+ if (_inverse_logic)
+ {
+ for (byte mask = 0x01; mask; mask <<= 1)
+ {
+ if (b & mask) // choose bit
+ tx_pin_write(LOW); // send 1
+ else
+ tx_pin_write(HIGH); // send 0
+
+ tunedDelay(_tx_delay);
+ }
+
+ tx_pin_write(LOW); // restore pin to natural state
+ }
+ else
+ {
+ for (byte mask = 0x01; mask; mask <<= 1)
+ {
+ if (b & mask) // choose bit
+ tx_pin_write(HIGH); // send 1
+ else
+ tx_pin_write(LOW); // send 0
+
+ tunedDelay(_tx_delay);
+ }
+
+ tx_pin_write(HIGH); // restore pin to natural state
+ }
+
+ SREG = oldSREG; // turn interrupts back on
+ tunedDelay(_tx_delay);
+}
+
+void SoftwareSerial::flush()
+{
+ if (!isListening())
+ return;
+
+ uint8_t oldSREG = SREG;
+ cli();
+ _receive_buffer_head = _receive_buffer_tail = 0;
+ SREG = oldSREG;
+}
+
+int SoftwareSerial::peek()
+{
+ if (!isListening())
+ return -1;
+
+ // Empty buffer?
+ if (_receive_buffer_head == _receive_buffer_tail)
+ return -1;
+
+ // Read from "head"
+ return _receive_buffer[_receive_buffer_head];
+}
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