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561 lines
14 KiB
561 lines
14 KiB
/* |
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I2C.cpp - I2C library |
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Copyright (c) 2011 Wayne Truchsess. All right reserved. |
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Rev 2.0 - September 19th, 2011 |
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- Added support for timeout function to prevent |
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and recover from bus lockup (thanks to PaulS |
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and CrossRoads on the Arduino forum) |
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- Changed return type for stop() from void to |
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uint8_t to handle timeOut function |
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Rev 1.0 - August 8th, 2011 |
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This is a modified version of the Arduino Wire/TWI |
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library. Functions were rewritten to provide more functionality |
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and also the use of Repeated Start. Some I2C devices will not |
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function correctly without the use of a Repeated Start. The |
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initial version of this library only supports the Master. |
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This library is free software; you can redistribute it and/or |
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modify it under the terms of the GNU Lesser General Public |
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License as published by the Free Software Foundation; either |
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version 2.1 of the License, or (at your option) any later version. |
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This library is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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Lesser General Public License for more details. |
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You should have received a copy of the GNU Lesser General Public |
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License along with this library; if not, write to the Free Software |
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include <inttypes.h> |
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#include "I2C.h" |
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#if defined(ARDUINO) && ARDUINO >= 100 |
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#include "Arduino.h" |
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#else |
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#include "WProgram.h" |
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#endif |
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uint8_t I2C::bytesAvailable = 0; |
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uint8_t I2C::bufferIndex = 0; |
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uint8_t I2C::totalBytes = 0; |
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uint16_t I2C::timeOutDelay = 0; |
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I2C::I2C() |
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{ |
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} |
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////////////// Public Methods //////////////////////////////////////// |
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void I2C::begin() |
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{ |
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#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega8__) || defined(__AVR_ATmega328P__) |
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// activate internal pull-ups for twi |
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// as per note from atmega8 manual pg167 |
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sbi(PORTC, 4); |
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sbi(PORTC, 5); |
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#else |
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// activate internal pull-ups for twi |
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// as per note from atmega128 manual pg204 |
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sbi(PORTD, 0); |
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sbi(PORTD, 1); |
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#endif |
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// initialize twi prescaler and bit rate |
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cbi(TWSR, TWPS0); |
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cbi(TWSR, TWPS1); |
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TWBR = ((CPU_FREQ / 100000) - 16) / 2; |
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// enable twi module, acks, and twi interrupt |
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TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA); |
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} |
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void I2C::end() |
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{ |
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TWCR = 0; |
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} |
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void I2C::timeOut(uint16_t _timeOut) |
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{ |
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timeOutDelay = _timeOut; |
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} |
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void I2C::setSpeed(boolean _fast) |
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{ |
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if(!_fast) |
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{ |
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TWBR = ((CPU_FREQ / 100000) - 16) / 2; |
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} |
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else |
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{ |
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TWBR = ((CPU_FREQ / 400000) - 16) / 2; |
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} |
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} |
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void I2C::pullup(boolean activate) |
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{ |
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if(activate) |
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{ |
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#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega8__) || defined(__AVR_ATmega328P__) |
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// activate internal pull-ups for twi |
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// as per note from atmega8 manual pg167 |
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sbi(PORTC, 4); |
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sbi(PORTC, 5); |
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#else |
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// activate internal pull-ups for twi |
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// as per note from atmega128 manual pg204 |
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sbi(PORTD, 0); |
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sbi(PORTD, 1); |
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#endif |
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} |
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else |
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{ |
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#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega8__) || defined(__AVR_ATmega328P__) |
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// deactivate internal pull-ups for twi |
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// as per note from atmega8 manual pg167 |
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cbi(PORTC, 4); |
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cbi(PORTC, 5); |
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#else |
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// deactivate internal pull-ups for twi |
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// as per note from atmega128 manual pg204 |
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cbi(PORTD, 0); |
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cbi(PORTD, 1); |
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#endif |
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} |
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} |
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/////////////carry over from Wire library /////////// |
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uint8_t I2C::beginTransmission(uint8_t address) |
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{ |
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returnStatusWire = 0; |
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returnStatus = 0; |
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returnStatus = start(); |
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returnStatusWire = returnStatus; |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendAddress(SLA_W(address)); |
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returnStatusWire = returnStatus; |
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return(returnStatus); |
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} |
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uint8_t I2C::beginTransmission(int address) |
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{ |
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return(beginTransmission((uint8_t) address)); |
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} |
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uint8_t I2C::send(uint8_t databyte) |
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{ |
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if(returnStatusWire) |
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{ |
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return(returnStatusWire); |
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} |
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returnStatus = 0; |
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returnStatus = sendByte(databyte); |
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returnStatusWire = returnStatus; |
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return(returnStatus); |
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} |
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uint8_t I2C::send(int databyte) |
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{ |
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return(send((uint8_t) databyte)); |
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} |
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uint8_t I2C::endTransmission() |
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{ |
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stop(); |
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return(returnStatusWire); |
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} |
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uint8_t I2C::requestFrom(int address, int numberBytes) |
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{ |
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return(requestFrom((uint8_t) address, (uint8_t) numberBytes)); |
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} |
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uint8_t I2C::requestFrom(uint8_t address, uint8_t numberBytes) |
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{ |
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returnStatus = 0; |
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returnStatus = read(address,numberBytes); |
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if(!returnStatus) |
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{ |
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return(numberBytes); |
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} |
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return(0); |
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} |
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uint8_t I2C::available() |
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{ |
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return(bytesAvailable); |
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} |
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uint8_t I2C::receive() |
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{ |
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bufferIndex = totalBytes - bytesAvailable; |
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if(!bytesAvailable) |
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{ |
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bufferIndex = 0; |
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return(0); |
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} |
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bytesAvailable--; |
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return(data[bufferIndex]); |
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} |
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///////////////////////////////////////////////////// |
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uint8_t I2C::write(uint8_t address, uint8_t registerAddress) |
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{ |
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returnStatus = 0; |
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returnStatus = start(); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendAddress(SLA_W(address)); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendByte(registerAddress); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = stop(); |
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return(returnStatus); |
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} |
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uint8_t I2C::write(int address, int registerAddress) |
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{ |
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return(write((uint8_t) address, (uint8_t) registerAddress)); |
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} |
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uint8_t I2C::write(uint8_t address, uint8_t registerAddress, uint8_t databyte) |
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{ |
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returnStatus = 0; |
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returnStatus = start(); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendAddress(SLA_W(address)); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendByte(registerAddress); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendByte(databyte); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = stop(); |
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return(returnStatus); |
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} |
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uint8_t I2C::write(int address, int registerAddress, int databyte) |
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{ |
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return(write((uint8_t) address, (uint8_t) registerAddress, (uint8_t) databyte)); |
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} |
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uint8_t I2C::write(uint8_t address, uint8_t registerAddress, char *databytes) |
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{ |
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uint8_t bufferLength = strlen(databytes); |
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returnStatus = 0; |
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returnStatus = write(address, registerAddress, (uint8_t*)databytes, bufferLength); |
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return(returnStatus); |
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} |
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uint8_t I2C::write(uint8_t address, uint8_t registerAddress, uint8_t *databytes, uint8_t numberBytes) |
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{ |
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returnStatus = 0; |
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returnStatus = start(); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendAddress(SLA_W(address)); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendByte(registerAddress); |
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if(returnStatus){return(returnStatus);} |
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for (uint8_t i = 0; i < numberBytes; i++) |
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{ |
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returnStatus = sendByte(databytes[i]); |
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if(returnStatus){return(returnStatus);} |
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} |
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returnStatus = stop(); |
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return(returnStatus); |
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} |
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uint8_t I2C::read(int address, int numberBytes) |
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{ |
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return(read((uint8_t) address, (uint8_t) numberBytes)); |
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} |
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uint8_t I2C::read(uint8_t address, uint8_t numberBytes) |
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{ |
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bytesAvailable = 0; |
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bufferIndex = 0; |
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if(numberBytes == 0){numberBytes++;} |
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nack = numberBytes - 1; |
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returnStatus = 0; |
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returnStatus = start(); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendAddress(SLA_R(address)); |
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if(returnStatus){return(returnStatus);} |
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for(uint8_t i = 0; i < numberBytes; i++) |
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{ |
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if( i == nack ) |
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{ |
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returnStatus = receiveByte(0); |
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if(returnStatus != MR_DATA_NACK){return(returnStatus);} |
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} |
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else |
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{ |
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returnStatus = receiveByte(1); |
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if(returnStatus != MR_DATA_ACK){return(returnStatus);} |
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} |
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data[i] = TWDR; |
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bytesAvailable = i+1; |
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totalBytes = i+1; |
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} |
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returnStatus = stop(); |
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return(returnStatus); |
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} |
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uint8_t I2C::read(int address, int registerAddress, int numberBytes) |
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{ |
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return(read((uint8_t) address, (uint8_t) registerAddress, (uint8_t) numberBytes)); |
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} |
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uint8_t I2C::read(uint8_t address, uint8_t registerAddress, uint8_t numberBytes) |
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{ |
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bytesAvailable = 0; |
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bufferIndex = 0; |
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if(numberBytes == 0){numberBytes++;} |
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nack = numberBytes - 1; |
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returnStatus = 0; |
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returnStatus = start(); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendAddress(SLA_W(address)); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendByte(registerAddress); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = start(); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendAddress(SLA_R(address)); |
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if(returnStatus){return(returnStatus);} |
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for(uint8_t i = 0; i < numberBytes; i++) |
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{ |
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if( i == nack ) |
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{ |
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returnStatus = receiveByte(0); |
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if(returnStatus != MR_DATA_NACK){return(returnStatus);} |
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} |
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else |
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{ |
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returnStatus = receiveByte(1); |
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if(returnStatus != MR_DATA_ACK){return(returnStatus);} |
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} |
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data[i] = TWDR; |
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bytesAvailable = i+1; |
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totalBytes = i+1; |
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} |
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returnStatus = stop(); |
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return(returnStatus); |
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} |
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uint8_t I2C::read(uint8_t address, uint8_t numberBytes, uint8_t *dataBuffer) |
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{ |
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bytesAvailable = 0; |
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bufferIndex = 0; |
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if(numberBytes == 0){numberBytes++;} |
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nack = numberBytes - 1; |
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returnStatus = 0; |
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returnStatus = start(); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendAddress(SLA_R(address)); |
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if(returnStatus){return(returnStatus);} |
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for(uint8_t i = 0; i < numberBytes; i++) |
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{ |
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if( i == nack ) |
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{ |
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returnStatus = receiveByte(0); |
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if(returnStatus != MR_DATA_NACK){return(returnStatus);} |
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} |
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else |
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{ |
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returnStatus = receiveByte(1); |
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if(returnStatus != MR_DATA_ACK){return(returnStatus);} |
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} |
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dataBuffer[i] = TWDR; |
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bytesAvailable = i+1; |
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totalBytes = i+1; |
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} |
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returnStatus = stop(); |
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return(returnStatus); |
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} |
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uint8_t I2C::read(uint8_t address, uint8_t registerAddress, uint8_t numberBytes, uint8_t *dataBuffer) |
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{ |
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bytesAvailable = 0; |
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bufferIndex = 0; |
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if(numberBytes == 0){numberBytes++;} |
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nack = numberBytes - 1; |
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returnStatus = 0; |
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returnStatus = start(); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendAddress(SLA_W(address)); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendByte(registerAddress); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = start(); |
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if(returnStatus){return(returnStatus);} |
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returnStatus = sendAddress(SLA_R(address)); |
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if(returnStatus){return(returnStatus);} |
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for(uint8_t i = 0; i < numberBytes; i++) |
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{ |
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if( i == nack ) |
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{ |
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returnStatus = receiveByte(0); |
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if(returnStatus != MR_DATA_NACK){return(returnStatus);} |
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} |
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else |
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{ |
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returnStatus = receiveByte(1); |
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if(returnStatus != MR_DATA_ACK){return(returnStatus);} |
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} |
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dataBuffer[i] = TWDR; |
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bytesAvailable = i+1; |
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totalBytes = i+1; |
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} |
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returnStatus = stop(); |
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return(returnStatus); |
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} |
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/////////////// Private Methods //////////////////////////////////////// |
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uint8_t I2C::start() |
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{ |
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unsigned long startingTime = millis(); |
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TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN); |
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while (!(TWCR & (1<<TWINT))) |
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{ |
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if(!timeOutDelay){continue;} |
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if((millis() - startingTime) >= timeOutDelay) |
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{ |
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lockUp(); |
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return(1); |
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} |
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} |
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if ((TWI_STATUS == START) || (TWI_STATUS == REPEATED_START)) |
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{ |
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return(0); |
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} |
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return(TWI_STATUS); |
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} |
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uint8_t I2C::sendAddress(uint8_t i2cAddress) |
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{ |
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TWDR = i2cAddress; |
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unsigned long startingTime = millis(); |
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TWCR = (1<<TWINT) | (1<<TWEN); |
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while (!(TWCR & (1<<TWINT))) |
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{ |
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if(!timeOutDelay){continue;} |
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if((millis() - startingTime) >= timeOutDelay) |
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{ |
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lockUp(); |
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return(1); |
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} |
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} |
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if ((TWI_STATUS == MT_SLA_ACK) || (TWI_STATUS == MR_SLA_ACK)) |
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{ |
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return(0); |
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} |
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return(TWI_STATUS); |
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} |
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uint8_t I2C::sendByte(uint8_t i2cData) |
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{ |
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TWDR = i2cData; |
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unsigned long startingTime = millis(); |
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TWCR = (1<<TWINT) | (1<<TWEN); |
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while (!(TWCR & (1<<TWINT))) |
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{ |
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if(!timeOutDelay){continue;} |
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if((millis() - startingTime) >= timeOutDelay) |
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{ |
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lockUp(); |
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return(1); |
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} |
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} |
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if (TWI_STATUS == MT_DATA_ACK) |
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{ |
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return(0); |
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} |
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return(TWI_STATUS); |
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} |
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uint8_t I2C::receiveByte(boolean ack) |
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{ |
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unsigned long startingTime = millis(); |
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if(ack) |
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{ |
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TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA); |
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} |
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else |
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{ |
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TWCR = (1<<TWINT) | (1<<TWEN); |
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} |
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while (!(TWCR & (1<<TWINT))) |
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{ |
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if(!timeOutDelay){continue;} |
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if((millis() - startingTime) >= timeOutDelay) |
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{ |
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lockUp(); |
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return(1); |
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} |
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} |
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return(TWI_STATUS); |
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} |
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uint8_t I2C::stop() |
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{ |
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unsigned long startingTime = millis(); |
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TWCR = (1<<TWINT)|(1<<TWEN)| (1<<TWSTO); |
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while ((TWCR & (1<<TWSTO))) |
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{ |
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if(!timeOutDelay){continue;} |
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if((millis() - startingTime) >= timeOutDelay) |
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{ |
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lockUp(); |
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return(1); |
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} |
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} |
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return(0); |
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} |
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void I2C::lockUp() |
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{ |
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TWCR = 0; //releases SDA and SCL lines to high impedance |
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TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA); //reinitialize TWI |
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} |
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SIGNAL(TWI_vect) |
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{ |
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switch(TWI_STATUS){ |
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case 0x20: |
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case 0x30: |
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case 0x48: |
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TWCR = (1<<TWINT)|(1<<TWEN)| (1<<TWSTO); // send a stop |
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break; |
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case 0x38: |
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case 0x68: |
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case 0x78: |
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case 0xB0: |
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TWCR = 0; //releases SDA and SCL lines to high impedance |
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TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA); //reinitialize TWI |
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break; |
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} |
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} |
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I2C I2c = I2C(); |
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