Added arduino libraries

arduino/LiquidCrystal.cpp

@@ -0,0 +1,326 @@
+#include "LiquidCrystal.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+#include "Arduino.h"
+
+// When the display powers up, it is configured as follows:
+//
+// 1. Display clear
+// 2. Function set: 
+//    DL = 1; 8-bit interface data 
+//    N = 0; 1-line display 
+//    F = 0; 5x8 dot character font 
+// 3. Display on/off control: 
+//    D = 0; Display off 
+//    C = 0; Cursor off 
+//    B = 0; Blinking off 
+// 4. Entry mode set: 
+//    I/D = 1; Increment by 1 
+//    S = 0; No shift 
+//
+// Note, however, that resetting the Arduino doesn't reset the LCD, so we
+// can't assume that its in that state when a sketch starts (and the
+// LiquidCrystal constructor is called).
+
+LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable,
+			     uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
+			     uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
+{
+  init(0, rs, rw, enable, d0, d1, d2, d3, d4, d5, d6, d7);
+}
+
+LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t enable,
+			     uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
+			     uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
+{
+  init(0, rs, 255, enable, d0, d1, d2, d3, d4, d5, d6, d7);
+}
+
+LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable,
+			     uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
+{
+  init(1, rs, rw, enable, d0, d1, d2, d3, 0, 0, 0, 0);
+}
+
+LiquidCrystal::LiquidCrystal(uint8_t rs,  uint8_t enable,
+			     uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
+{
+  init(1, rs, 255, enable, d0, d1, d2, d3, 0, 0, 0, 0);
+}
+
+void LiquidCrystal::init(uint8_t fourbitmode, uint8_t rs, uint8_t rw, uint8_t enable,
+			 uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
+			 uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
+{
+  _rs_pin = rs;
+  _rw_pin = rw;
+  _enable_pin = enable;
+  
+  _data_pins[0] = d0;
+  _data_pins[1] = d1;
+  _data_pins[2] = d2;
+  _data_pins[3] = d3; 
+  _data_pins[4] = d4;
+  _data_pins[5] = d5;
+  _data_pins[6] = d6;
+  _data_pins[7] = d7; 
+
+  if (fourbitmode)
+    _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
+  else 
+    _displayfunction = LCD_8BITMODE | LCD_1LINE | LCD_5x8DOTS;
+  
+  begin(16, 1);  
+}
+
+void LiquidCrystal::begin(uint8_t cols, uint8_t lines, uint8_t dotsize) {
+  if (lines > 1) {
+    _displayfunction |= LCD_2LINE;
+  }
+  _numlines = lines;
+
+  setRowOffsets(0x00, 0x40, 0x00 + cols, 0x40 + cols);  
+
+  // for some 1 line displays you can select a 10 pixel high font
+  if ((dotsize != LCD_5x8DOTS) && (lines == 1)) {
+    _displayfunction |= LCD_5x10DOTS;
+  }
+
+  pinMode(_rs_pin, OUTPUT);
+  // we can save 1 pin by not using RW. Indicate by passing 255 instead of pin#
+  if (_rw_pin != 255) { 
+    pinMode(_rw_pin, OUTPUT);
+  }
+  pinMode(_enable_pin, OUTPUT);
+  
+  // Do these once, instead of every time a character is drawn for speed reasons.
+  for (int i=0; i<((_displayfunction & LCD_8BITMODE) ? 8 : 4); ++i)
+  {
+    pinMode(_data_pins[i], OUTPUT);
+   } 
+
+  // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
+  // according to datasheet, we need at least 40ms after power rises above 2.7V
+  // before sending commands. Arduino can turn on way before 4.5V so we'll wait 50
+  delayMicroseconds(50000); 
+  // Now we pull both RS and R/W low to begin commands
+  digitalWrite(_rs_pin, LOW);
+  digitalWrite(_enable_pin, LOW);
+  if (_rw_pin != 255) { 
+    digitalWrite(_rw_pin, LOW);
+  }
+  
+  //put the LCD into 4 bit or 8 bit mode
+  if (! (_displayfunction & LCD_8BITMODE)) {
+    // this is according to the hitachi HD44780 datasheet
+    // figure 24, pg 46
+
+    // we start in 8bit mode, try to set 4 bit mode
+    write4bits(0x03);
+    delayMicroseconds(4500); // wait min 4.1ms
+
+    // second try
+    write4bits(0x03);
+    delayMicroseconds(4500); // wait min 4.1ms
+    
+    // third go!
+    write4bits(0x03); 
+    delayMicroseconds(150);
+
+    // finally, set to 4-bit interface
+    write4bits(0x02); 
+  } else {
+    // this is according to the hitachi HD44780 datasheet
+    // page 45 figure 23
+
+    // Send function set command sequence
+    command(LCD_FUNCTIONSET | _displayfunction);
+    delayMicroseconds(4500);  // wait more than 4.1ms
+
+    // second try
+    command(LCD_FUNCTIONSET | _displayfunction);
+    delayMicroseconds(150);
+
+    // third go
+    command(LCD_FUNCTIONSET | _displayfunction);
+  }
+
+  // finally, set # lines, font size, etc.
+  command(LCD_FUNCTIONSET | _displayfunction);  
+
+  // turn the display on with no cursor or blinking default
+  _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;  
+  display();
+
+  // clear it off
+  clear();
+
+  // Initialize to default text direction (for romance languages)
+  _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
+  // set the entry mode
+  command(LCD_ENTRYMODESET | _displaymode);
+
+}
+
+void LiquidCrystal::setRowOffsets(int row0, int row1, int row2, int row3)
+{
+  _row_offsets[0] = row0;
+  _row_offsets[1] = row1;
+  _row_offsets[2] = row2;
+  _row_offsets[3] = row3;
+}
+
+/********** high level commands, for the user! */
+void LiquidCrystal::clear()
+{
+  command(LCD_CLEARDISPLAY);  // clear display, set cursor position to zero
+  delayMicroseconds(2000);  // this command takes a long time!
+}
+
+void LiquidCrystal::home()
+{
+  command(LCD_RETURNHOME);  // set cursor position to zero
+  delayMicroseconds(2000);  // this command takes a long time!
+}
+
+void LiquidCrystal::setCursor(uint8_t col, uint8_t row)
+{
+  const size_t max_lines = sizeof(_row_offsets) / sizeof(*_row_offsets);
+  if ( row >= max_lines ) {
+    row = max_lines - 1;    // we count rows starting w/0
+  }
+  if ( row >= _numlines ) {
+    row = _numlines - 1;    // we count rows starting w/0
+  }
+  
+  command(LCD_SETDDRAMADDR | (col + _row_offsets[row]));
+}
+
+// Turn the display on/off (quickly)
+void LiquidCrystal::noDisplay() {
+  _displaycontrol &= ~LCD_DISPLAYON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+void LiquidCrystal::display() {
+  _displaycontrol |= LCD_DISPLAYON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+
+// Turns the underline cursor on/off
+void LiquidCrystal::noCursor() {
+  _displaycontrol &= ~LCD_CURSORON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+void LiquidCrystal::cursor() {
+  _displaycontrol |= LCD_CURSORON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+
+// Turn on and off the blinking cursor
+void LiquidCrystal::noBlink() {
+  _displaycontrol &= ~LCD_BLINKON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+void LiquidCrystal::blink() {
+  _displaycontrol |= LCD_BLINKON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+
+// These commands scroll the display without changing the RAM
+void LiquidCrystal::scrollDisplayLeft(void) {
+  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
+}
+void LiquidCrystal::scrollDisplayRight(void) {
+  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
+}
+
+// This is for text that flows Left to Right
+void LiquidCrystal::leftToRight(void) {
+  _displaymode |= LCD_ENTRYLEFT;
+  command(LCD_ENTRYMODESET | _displaymode);
+}
+
+// This is for text that flows Right to Left
+void LiquidCrystal::rightToLeft(void) {
+  _displaymode &= ~LCD_ENTRYLEFT;
+  command(LCD_ENTRYMODESET | _displaymode);
+}
+
+// This will 'right justify' text from the cursor
+void LiquidCrystal::autoscroll(void) {
+  _displaymode |= LCD_ENTRYSHIFTINCREMENT;
+  command(LCD_ENTRYMODESET | _displaymode);
+}
+
+// This will 'left justify' text from the cursor
+void LiquidCrystal::noAutoscroll(void) {
+  _displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
+  command(LCD_ENTRYMODESET | _displaymode);
+}
+
+// Allows us to fill the first 8 CGRAM locations
+// with custom characters
+void LiquidCrystal::createChar(uint8_t location, uint8_t charmap[]) {
+  location &= 0x7; // we only have 8 locations 0-7
+  command(LCD_SETCGRAMADDR | (location << 3));
+  for (int i=0; i<8; i++) {
+    write(charmap[i]);
+  }
+}
+
+/*********** mid level commands, for sending data/cmds */
+
+inline void LiquidCrystal::command(uint8_t value) {
+  send(value, LOW);
+}
+
+inline size_t LiquidCrystal::write(uint8_t value) {
+  send(value, HIGH);
+  return 1; // assume sucess
+}
+
+/************ low level data pushing commands **********/
+
+// write either command or data, with automatic 4/8-bit selection
+void LiquidCrystal::send(uint8_t value, uint8_t mode) {
+  digitalWrite(_rs_pin, mode);
+
+  // if there is a RW pin indicated, set it low to Write
+  if (_rw_pin != 255) { 
+    digitalWrite(_rw_pin, LOW);
+  }
+  
+  if (_displayfunction & LCD_8BITMODE) {
+    write8bits(value); 
+  } else {
+    write4bits(value>>4);
+    write4bits(value);
+  }
+}
+
+void LiquidCrystal::pulseEnable(void) {
+  digitalWrite(_enable_pin, LOW);
+  delayMicroseconds(1);    
+  digitalWrite(_enable_pin, HIGH);
+  delayMicroseconds(1);    // enable pulse must be >450ns
+  digitalWrite(_enable_pin, LOW);
+  delayMicroseconds(100);   // commands need > 37us to settle
+}
+
+void LiquidCrystal::write4bits(uint8_t value) {
+  for (int i = 0; i < 4; i++) {
+    digitalWrite(_data_pins[i], (value >> i) & 0x01);
+  }
+
+  pulseEnable();
+}
+
+void LiquidCrystal::write8bits(uint8_t value) {
+  for (int i = 0; i < 8; i++) {
+    digitalWrite(_data_pins[i], (value >> i) & 0x01);
+  }
+  
+  pulseEnable();
+}

arduino/LiquidCrystal.h

@@ -0,0 +1,139 @@
+/*
+CONTENTS FROM INCLUDED LICENSE FILE:
+
+    = Liquid Crystal Library for Arduino =
+
+    This library allows an Arduino board to control LiquidCrystal displays (LCDs) based on the Hitachi HD44780 (or a compatible) chipset, which is found on most text-based LCDs.
+
+    For more information about this library please visit us at
+    http://www.arduino.cc/en/Reference/LiquidCrystal
+
+    == License ==
+
+    Copyright (C) 2006-2008 Hans-Christoph Steiner. All rights reserved.
+    Copyright (c) 2010 Arduino LLC. All right reserved.
+
+    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
+
+*/
+
+#ifndef LiquidCrystal_h
+#define LiquidCrystal_h
+
+#include <inttypes.h>
+#include "Print.h"
+
+// commands
+#define LCD_CLEARDISPLAY 0x01
+#define LCD_RETURNHOME 0x02
+#define LCD_ENTRYMODESET 0x04
+#define LCD_DISPLAYCONTROL 0x08
+#define LCD_CURSORSHIFT 0x10
+#define LCD_FUNCTIONSET 0x20
+#define LCD_SETCGRAMADDR 0x40
+#define LCD_SETDDRAMADDR 0x80
+
+// flags for display entry mode
+#define LCD_ENTRYRIGHT 0x00
+#define LCD_ENTRYLEFT 0x02
+#define LCD_ENTRYSHIFTINCREMENT 0x01
+#define LCD_ENTRYSHIFTDECREMENT 0x00
+
+// flags for display on/off control
+#define LCD_DISPLAYON 0x04
+#define LCD_DISPLAYOFF 0x00
+#define LCD_CURSORON 0x02
+#define LCD_CURSOROFF 0x00
+#define LCD_BLINKON 0x01
+#define LCD_BLINKOFF 0x00
+
+// flags for display/cursor shift
+#define LCD_DISPLAYMOVE 0x08
+#define LCD_CURSORMOVE 0x00
+#define LCD_MOVERIGHT 0x04
+#define LCD_MOVELEFT 0x00
+
+// flags for function set
+#define LCD_8BITMODE 0x10
+#define LCD_4BITMODE 0x00
+#define LCD_2LINE 0x08
+#define LCD_1LINE 0x00
+#define LCD_5x10DOTS 0x04
+#define LCD_5x8DOTS 0x00
+
+class LiquidCrystal : public Print {
+public:
+  LiquidCrystal(uint8_t rs, uint8_t enable,
+		uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
+		uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7);
+  LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable,
+		uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
+		uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7);
+  LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable,
+		uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3);
+  LiquidCrystal(uint8_t rs, uint8_t enable,
+		uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3);
+
+  void init(uint8_t fourbitmode, uint8_t rs, uint8_t rw, uint8_t enable,
+	    uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
+	    uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7);
+    
+  void begin(uint8_t cols, uint8_t rows, uint8_t charsize = LCD_5x8DOTS);
+
+  void clear();
+  void home();
+
+  void noDisplay();
+  void display();
+  void noBlink();
+  void blink();
+  void noCursor();
+  void cursor();
+  void scrollDisplayLeft();
+  void scrollDisplayRight();
+  void leftToRight();
+  void rightToLeft();
+  void autoscroll();
+  void noAutoscroll();
+
+  void setRowOffsets(int row1, int row2, int row3, int row4);
+  void createChar(uint8_t, uint8_t[]);
+  void setCursor(uint8_t, uint8_t); 
+  virtual size_t write(uint8_t);
+  void command(uint8_t);
+  
+  using Print::write;
+private:
+  void send(uint8_t, uint8_t);
+  void write4bits(uint8_t);
+  void write8bits(uint8_t);
+  void pulseEnable();
+
+  uint8_t _rs_pin; // LOW: command.  HIGH: character.
+  uint8_t _rw_pin; // LOW: write to LCD.  HIGH: read from LCD.
+  uint8_t _enable_pin; // activated by a HIGH pulse.
+  uint8_t _data_pins[8];
+
+  uint8_t _displayfunction;
+  uint8_t _displaycontrol;
+  uint8_t _displaymode;
+
+  uint8_t _initialized;
+
+  uint8_t _numlines;
+  uint8_t _row_offsets[4];
+};
+
+#endif

arduino/SoftwareSerial.cpp

@@ -0,0 +1,486 @@
+/*
+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 <util/delay_basic.h>
+
+//
+// Statics
+//
+SoftwareSerial *SoftwareSerial::active_object = 0;
+uint8_t 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.
+#if _DEBUG
+inline void DebugPulse(uint8_t pin, uint8_t count)
+{
+  volatile uint8_t *pport = portOutputRegister(digitalPinToPort(pin));
+
+  uint8_t val = *pport;
+  while (count--)
+  {
+    *pport = val | digitalPinToBitMask(pin);
+    *pport = val;
+  }
+}
+#else
+inline void DebugPulse(uint8_t, uint8_t) {}
+#endif
+
+//
+// Private methods
+//
+
+/* static */ 
+inline void SoftwareSerial::tunedDelay(uint16_t delay) { 
+  _delay_loop_2(delay);
+}
+
+// This function sets the current object as the "listening"
+// one and returns true if it replaces another 
+bool SoftwareSerial::listen()
+{
+  if (!_rx_delay_stopbit)
+    return false;
+
+  if (active_object != this)
+  {
+    if (active_object)
+      active_object->stopListening();
+
+    _buffer_overflow = false;
+    _receive_buffer_head = _receive_buffer_tail = 0;
+    active_object = this;
+
+    setRxIntMsk(true);
+    return true;
+  }
+
+  return false;
+}
+
+// Stop listening. Returns true if we were actually listening.
+bool SoftwareSerial::stopListening()
+{
+  if (active_object == this)
+  {
+    setRxIntMsk(false);
+    active_object = NULL;
+    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())
+  {
+    // Disable further interrupts during reception, this prevents
+    // triggering another interrupt directly after we return, which can
+    // cause problems at higher baudrates.
+    setRxIntMsk(false);
+
+    // 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=8; i > 0; --i)
+    {
+      tunedDelay(_rx_delay_intrabit);
+      d >>= 1;
+      DebugPulse(_DEBUG_PIN2, 1);
+      if (rx_pin_read())
+        d |= 0x80;
+    }
+
+    if (_inverse_logic)
+      d = ~d;
+
+    // if buffer full, set the overflow flag and return
+    uint8_t next = (_receive_buffer_tail + 1) % _SS_MAX_RX_BUFF;
+    if (next != _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 = next;
+    } 
+    else 
+    {
+      DebugPulse(_DEBUG_PIN1, 1);
+      _buffer_overflow = true;
+    }
+
+    // skip the stop bit
+    tunedDelay(_rx_delay_stopbit);
+    DebugPulse(_DEBUG_PIN1, 1);
+
+    // Re-enable interrupts when we're sure to be inside the stop bit
+    setRxIntMsk(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
+}
+
+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, ISR_ALIASOF(PCINT0_vect));
+#endif
+
+#if defined(PCINT2_vect)
+ISR(PCINT2_vect, ISR_ALIASOF(PCINT0_vect));
+#endif
+
+#if defined(PCINT3_vect)
+ISR(PCINT3_vect, ISR_ALIASOF(PCINT0_vect));
+#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)
+{
+  // First write, then set output. If we do this the other way around,
+  // the pin would be output low for a short while before switching to
+  // output high. Now, it is input with pullup for a short while, which
+  // is fine. With inverse logic, either order is fine.
+  digitalWrite(tx, _inverse_logic ? LOW : HIGH);
+  pinMode(tx, OUTPUT);
+  _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);
+}
+
+uint16_t SoftwareSerial::subtract_cap(uint16_t num, uint16_t sub) {
+  if (num > sub)
+    return num - sub;
+  else
+    return 1;
+}
+
+//
+// Public methods
+//
+
+void SoftwareSerial::begin(long speed)
+{
+  _rx_delay_centering = _rx_delay_intrabit = _rx_delay_stopbit = _tx_delay = 0;
+
+  // Precalculate the various delays, in number of 4-cycle delays
+  uint16_t bit_delay = (F_CPU / speed) / 4;
+
+  // 12 (gcc 4.8.2) or 13 (gcc 4.3.2) cycles from start bit to first bit,
+  // 15 (gcc 4.8.2) or 16 (gcc 4.3.2) cycles between bits,
+  // 12 (gcc 4.8.2) or 14 (gcc 4.3.2) cycles from last bit to stop bit
+  // These are all close enough to just use 15 cycles, since the inter-bit
+  // timings are the most critical (deviations stack 8 times)
+  _tx_delay = subtract_cap(bit_delay, 15 / 4);
+
+  // Only setup rx when we have a valid PCINT for this pin
+  if (digitalPinToPCICR((int8_t)_receivePin)) {
+    #if GCC_VERSION > 40800
+    // Timings counted from gcc 4.8.2 output. This works up to 115200 on
+    // 16Mhz and 57600 on 8Mhz.
+    //
+    // When the start bit occurs, there are 3 or 4 cycles before the
+    // interrupt flag is set, 4 cycles before the PC is set to the right
+    // interrupt vector address and the old PC is pushed on the stack,
+    // and then 75 cycles of instructions (including the RJMP in the
+    // ISR vector table) until the first delay. After the delay, there
+    // are 17 more cycles until the pin value is read (excluding the
+    // delay in the loop).
+    // We want to have a total delay of 1.5 bit time. Inside the loop,
+    // we already wait for 1 bit time - 23 cycles, so here we wait for
+    // 0.5 bit time - (71 + 18 - 22) cycles.
+    _rx_delay_centering = subtract_cap(bit_delay / 2, (4 + 4 + 75 + 17 - 23) / 4);
+
+    // There are 23 cycles in each loop iteration (excluding the delay)
+    _rx_delay_intrabit = subtract_cap(bit_delay, 23 / 4);
+
+    // There are 37 cycles from the last bit read to the start of
+    // stopbit delay and 11 cycles from the delay until the interrupt
+    // mask is enabled again (which _must_ happen during the stopbit).
+    // This delay aims at 3/4 of a bit time, meaning the end of the
+    // delay will be at 1/4th of the stopbit. This allows some extra
+    // time for ISR cleanup, which makes 115200 baud at 16Mhz work more
+    // reliably
+    _rx_delay_stopbit = subtract_cap(bit_delay * 3 / 4, (37 + 11) / 4);
+    #else // Timings counted from gcc 4.3.2 output
+    // Note that this code is a _lot_ slower, mostly due to bad register
+    // allocation choices of gcc. This works up to 57600 on 16Mhz and
+    // 38400 on 8Mhz.
+    _rx_delay_centering = subtract_cap(bit_delay / 2, (4 + 4 + 97 + 29 - 11) / 4);
+    _rx_delay_intrabit = subtract_cap(bit_delay, 11 / 4);
+    _rx_delay_stopbit = subtract_cap(bit_delay * 3 / 4, (44 + 17) / 4);
+    #endif
+
+
+    // Enable the PCINT for the entire port here, but never disable it
+    // (others might also need it, so we disable the interrupt by using
+    // the per-pin PCMSK register).
+    *digitalPinToPCICR((int8_t)_receivePin) |= _BV(digitalPinToPCICRbit(_receivePin));
+    // Precalculate the pcint mask register and value, so setRxIntMask
+    // can be used inside the ISR without costing too much time.
+    _pcint_maskreg = digitalPinToPCMSK(_receivePin);
+    _pcint_maskvalue = _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::setRxIntMsk(bool enable)
+{
+    if (enable)
+      *_pcint_maskreg |= _pcint_maskvalue;
+    else
+      *_pcint_maskreg &= ~_pcint_maskvalue;
+}
+
+void SoftwareSerial::end()
+{
+  stopListening();
+}
+
+
+// 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 ((unsigned int)(_receive_buffer_tail + _SS_MAX_RX_BUFF - _receive_buffer_head)) % _SS_MAX_RX_BUFF;
+}
+
+size_t SoftwareSerial::write(uint8_t b)
+{
+  if (_tx_delay == 0) {
+    setWriteError();
+    return 0;
+  }
+
+  // By declaring these as local variables, the compiler will put them
+  // in registers _before_ disabling interrupts and entering the
+  // critical timing sections below, which makes it a lot easier to
+  // verify the cycle timings
+  volatile uint8_t *reg = _transmitPortRegister;
+  uint8_t reg_mask = _transmitBitMask;
+  uint8_t inv_mask = ~_transmitBitMask;
+  uint8_t oldSREG = SREG;
+  bool inv = _inverse_logic;
+  uint16_t delay = _tx_delay;
+
+  if (inv)
+    b = ~b;
+
+  cli();  // turn off interrupts for a clean txmit
+
+  // Write the start bit
+  if (inv)
+    *reg |= reg_mask;
+  else
+    *reg &= inv_mask;
+
+  tunedDelay(delay);
+
+  // Write each of the 8 bits
+  for (uint8_t i = 8; i > 0; --i)
+  {
+    if (b & 1) // choose bit
+      *reg |= reg_mask; // send 1
+    else
+      *reg &= inv_mask; // send 0
+
+    tunedDelay(delay);
+    b >>= 1;
+  }
+
+  // restore pin to natural state
+  if (inv)
+    *reg &= inv_mask;
+  else
+    *reg |= reg_mask;
+
+  SREG = oldSREG; // turn interrupts back on
+  tunedDelay(_tx_delay);
+  
+  return 1;
+}
+
+void SoftwareSerial::flush()
+{
+  // There is no tx buffering, simply return
+}
+
+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];
+}

arduino/SoftwareSerial.h

@@ -0,0 +1,114 @@
+/*
+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
+******************************************************************************/
+
+#ifndef _SS_MAX_RX_BUFF
+#define _SS_MAX_RX_BUFF 64 // RX buffer size
+#endif
+
+#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;
+  volatile uint8_t *_pcint_maskreg;
+  uint8_t _pcint_maskvalue;
+
+  // Expressed as 4-cycle delays (must never be 0!)
+  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 uint8_t _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
+  inline void recv() __attribute__((__always_inline__));
+  uint8_t rx_pin_read();
+  void setTX(uint8_t transmitPin);
+  void setRX(uint8_t receivePin);
+  inline void setRxIntMsk(bool enable) __attribute__((__always_inline__));
+
+  // Return num - sub, or 1 if the result would be < 1
+  static uint16_t subtract_cap(uint16_t num, uint16_t sub);
+
+  // 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();
+  operator bool() { return true; }
+  
+  using Print::write;
+
+  // public only for easy access by interrupt handlers
+  static inline void handle_interrupt() __attribute__((__always_inline__));
+};
+
+#endif