/* * I2C.cpp - I2C library * Copyright (c) 2011 Wayne Truchsess. All right reserved. * Rev 2.0 - September 19th, 2011 * - Added support for timeout function to prevent * and recover from bus lockup (thanks to PaulS * and CrossRoads on the Arduino forum) * - Changed return type for stop() from void to * uint8_t to handle timeOut function * Rev 1.0 - August 8th, 2011 * * This is a modified version of the Arduino Wire/TWI * library. Functions were rewritten to provide more functionality * and also the use of Repeated Start. Some I2C devices will not * function correctly without the use of a Repeated Start. The * initial version of this library only supports the Master. * * * 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 */ #include #include "I2C.h" uint8_t I2C::bytesAvailable = 0; uint8_t I2C::bufferIndex = 0; uint8_t I2C::totalBytes = 0; uint16_t I2C::timeOutDelay = 0; I2C::I2C() { } ////////////// Public Methods //////////////////////////////////////// void I2C::begin() { #if defined(__AVR_ATmega168__) || defined(__AVR_ATmega8__) || defined(__AVR_ATmega328P__) // activate internal pull-ups for twi // as per note from atmega8 manual pg167 sbi(PORTC, 4); sbi(PORTC, 5); #else // activate internal pull-ups for twi // as per note from atmega128 manual pg204 sbi(PORTD, 0); sbi(PORTD, 1); #endif // initialize twi prescaler and bit rate cbi(TWSR, TWPS0); cbi(TWSR, TWPS1); TWBR = ((CPU_FREQ / 100000) - 16) / 2; // enable twi module, acks, and twi interrupt TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA); } void I2C::end() { TWCR = 0; } void I2C::timeOut(uint16_t _timeOut) { timeOutDelay = _timeOut; } void I2C::setSpeed(boolean _fast) { if(!_fast) { TWBR = ((CPU_FREQ / 100000) - 16) / 2; } else { TWBR = ((CPU_FREQ / 400000) - 16) / 2; } } void I2C::pullup(boolean activate) { if(activate) { #if defined(__AVR_ATmega168__) || defined(__AVR_ATmega8__) || defined(__AVR_ATmega328P__) // activate internal pull-ups for twi // as per note from atmega8 manual pg167 sbi(PORTC, 4); sbi(PORTC, 5); #else // activate internal pull-ups for twi // as per note from atmega128 manual pg204 sbi(PORTD, 0); sbi(PORTD, 1); #endif } else { #if defined(__AVR_ATmega168__) || defined(__AVR_ATmega8__) || defined(__AVR_ATmega328P__) // deactivate internal pull-ups for twi // as per note from atmega8 manual pg167 cbi(PORTC, 4); cbi(PORTC, 5); #else // deactivate internal pull-ups for twi // as per note from atmega128 manual pg204 cbi(PORTD, 0); cbi(PORTD, 1); #endif } } /////////////carry over from Wire library /////////// uint8_t I2C::beginTransmission(uint8_t address) { returnStatusWire = 0; returnStatus = 0; returnStatus = start(); returnStatusWire = returnStatus; if(returnStatus) {return(returnStatus); } returnStatus = sendAddress(SLA_W(address)); returnStatusWire = returnStatus; return(returnStatus); } uint8_t I2C::beginTransmission(int address) { return(beginTransmission((uint8_t) address)); } uint8_t I2C::send(uint8_t databyte) { if(returnStatusWire) { return(returnStatusWire); } returnStatus = 0; returnStatus = sendByte(databyte); returnStatusWire = returnStatus; return(returnStatus); } uint8_t I2C::send(int databyte) { return(send((uint8_t) databyte)); } uint8_t I2C::endTransmission() { stop(); return(returnStatusWire); } uint8_t I2C::requestFrom(int address, int numberBytes) { return(requestFrom((uint8_t) address, (uint8_t) numberBytes)); } uint8_t I2C::requestFrom(uint8_t address, uint8_t numberBytes) { returnStatus = 0; returnStatus = read(address,numberBytes); if(!returnStatus) { return(numberBytes); } return(0); } uint8_t I2C::available() { return(bytesAvailable); } uint8_t I2C::receive() { bufferIndex = totalBytes - bytesAvailable; if(!bytesAvailable) { bufferIndex = 0; return(0); } bytesAvailable--; return(data[bufferIndex]); } ///////////////////////////////////////////////////// uint8_t I2C::write(uint8_t address, uint8_t registerAddress) { returnStatus = 0; returnStatus = start(); if(returnStatus) {return(returnStatus); } returnStatus = sendAddress(SLA_W(address)); if(returnStatus) {return(returnStatus); } returnStatus = sendByte(registerAddress); if(returnStatus) {return(returnStatus); } returnStatus = stop(); return(returnStatus); } uint8_t I2C::write(int address, int registerAddress) { return(write((uint8_t) address, (uint8_t) registerAddress)); } uint8_t I2C::write(uint8_t address, uint8_t registerAddress, uint8_t databyte) { returnStatus = 0; returnStatus = start(); if(returnStatus) {return(returnStatus); } returnStatus = sendAddress(SLA_W(address)); if(returnStatus) {return(returnStatus); } returnStatus = sendByte(registerAddress); if(returnStatus) {return(returnStatus); } returnStatus = sendByte(databyte); if(returnStatus) {return(returnStatus); } returnStatus = stop(); return(returnStatus); } uint8_t I2C::write(int address, int registerAddress, int databyte) { return(write((uint8_t) address, (uint8_t) registerAddress, (uint8_t) databyte)); } uint8_t I2C::write(uint8_t address, uint8_t registerAddress, char *databytes) { uint8_t bufferLength = strlen(databytes); returnStatus = 0; returnStatus = write(address, registerAddress, (uint8_t*)databytes, bufferLength); return(returnStatus); } uint8_t I2C::write(uint8_t address, uint8_t registerAddress, uint8_t *databytes, uint8_t numberBytes) { returnStatus = 0; returnStatus = start(); if(returnStatus) {return(returnStatus); } returnStatus = sendAddress(SLA_W(address)); if(returnStatus) {return(returnStatus); } returnStatus = sendByte(registerAddress); if(returnStatus) {return(returnStatus); } for (uint8_t i = 0; i < numberBytes; i++) { returnStatus = sendByte(databytes[i]); if(returnStatus) {return(returnStatus); } } returnStatus = stop(); return(returnStatus); } uint8_t I2C::read(int address, int numberBytes) { return(read((uint8_t) address, (uint8_t) numberBytes)); } uint8_t I2C::read(uint8_t address, uint8_t numberBytes) { bytesAvailable = 0; bufferIndex = 0; if(numberBytes == 0) {numberBytes++; } nack = numberBytes - 1; returnStatus = 0; returnStatus = start(); if(returnStatus) {return(returnStatus); } returnStatus = sendAddress(SLA_R(address)); if(returnStatus) {return(returnStatus); } for(uint8_t i = 0; i < numberBytes; i++) { if( i == nack ) { returnStatus = receiveByte(0); if(returnStatus != MR_DATA_NACK) {return(returnStatus); } } else { returnStatus = receiveByte(1); if(returnStatus != MR_DATA_ACK) {return(returnStatus); } } data[i] = TWDR; bytesAvailable = i+1; totalBytes = i+1; } returnStatus = stop(); return(returnStatus); } uint8_t I2C::read(int address, int registerAddress, int numberBytes) { return(read((uint8_t) address, (uint8_t) registerAddress, (uint8_t) numberBytes)); } uint8_t I2C::read(uint8_t address, uint8_t registerAddress, uint8_t numberBytes) { bytesAvailable = 0; bufferIndex = 0; if(numberBytes == 0) {numberBytes++; } nack = numberBytes - 1; returnStatus = 0; returnStatus = start(); if(returnStatus) {return(returnStatus); } returnStatus = sendAddress(SLA_W(address)); if(returnStatus) {return(returnStatus); } returnStatus = sendByte(registerAddress); if(returnStatus) {return(returnStatus); } returnStatus = start(); if(returnStatus) {return(returnStatus); } returnStatus = sendAddress(SLA_R(address)); if(returnStatus) {return(returnStatus); } for(uint8_t i = 0; i < numberBytes; i++) { if( i == nack ) { returnStatus = receiveByte(0); if(returnStatus != MR_DATA_NACK) {return(returnStatus); } } else { returnStatus = receiveByte(1); if(returnStatus != MR_DATA_ACK) {return(returnStatus); } } data[i] = TWDR; bytesAvailable = i+1; totalBytes = i+1; } returnStatus = stop(); return(returnStatus); } uint8_t I2C::read(uint8_t address, uint8_t numberBytes, uint8_t *dataBuffer) { bytesAvailable = 0; bufferIndex = 0; if(numberBytes == 0) {numberBytes++; } nack = numberBytes - 1; returnStatus = 0; returnStatus = start(); if(returnStatus) {return(returnStatus); } returnStatus = sendAddress(SLA_R(address)); if(returnStatus) {return(returnStatus); } for(uint8_t i = 0; i < numberBytes; i++) { if( i == nack ) { returnStatus = receiveByte(0); if(returnStatus != MR_DATA_NACK) {return(returnStatus); } } else { returnStatus = receiveByte(1); if(returnStatus != MR_DATA_ACK) {return(returnStatus); } } dataBuffer[i] = TWDR; bytesAvailable = i+1; totalBytes = i+1; } returnStatus = stop(); return(returnStatus); } uint8_t I2C::read(uint8_t address, uint8_t registerAddress, uint8_t numberBytes, uint8_t *dataBuffer) { bytesAvailable = 0; bufferIndex = 0; if(numberBytes == 0) {numberBytes++; } nack = numberBytes - 1; returnStatus = 0; returnStatus = start(); if (returnStatus) { _lockup_count++; return(returnStatus); } returnStatus = sendAddress(SLA_W(address)); if(returnStatus) { _lockup_count++; return(returnStatus); } returnStatus = sendByte(registerAddress); if(returnStatus) { _lockup_count++; return(returnStatus); } returnStatus = start(); if(returnStatus) { _lockup_count++; return(returnStatus); } returnStatus = sendAddress(SLA_R(address)); if(returnStatus) { _lockup_count++; return(returnStatus); } for(uint8_t i = 0; i < numberBytes; i++) { if( i == nack ) { returnStatus = receiveByte(0); if (returnStatus != MR_DATA_NACK) { _lockup_count++; return(returnStatus); } } else { returnStatus = receiveByte(1); if (returnStatus != MR_DATA_ACK) { _lockup_count++; return(returnStatus); } } dataBuffer[i] = TWDR; bytesAvailable = i+1; totalBytes = i+1; } returnStatus = stop(); if (returnStatus) { _lockup_count++; } return(returnStatus); } /////////////// Private Methods //////////////////////////////////////// uint8_t I2C::start() { unsigned long startingTime = millis(); TWCR = (1<= timeOutDelay) { lockUp(); return(1); } } if ((TWI_STATUS == START) || (TWI_STATUS == REPEATED_START)) { return(0); } return(TWI_STATUS); } uint8_t I2C::sendAddress(uint8_t i2cAddress) { TWDR = i2cAddress; unsigned long startingTime = millis(); TWCR = (1<= timeOutDelay) { lockUp(); return(1); } } if ((TWI_STATUS == MT_SLA_ACK) || (TWI_STATUS == MR_SLA_ACK)) { return(0); } return(TWI_STATUS); } uint8_t I2C::sendByte(uint8_t i2cData) { TWDR = i2cData; unsigned long startingTime = millis(); TWCR = (1<= timeOutDelay) { lockUp(); return(1); } } if (TWI_STATUS == MT_DATA_ACK) { return(0); } return(TWI_STATUS); } uint8_t I2C::receiveByte(boolean ack) { unsigned long startingTime = millis(); if(ack) { TWCR = (1<= timeOutDelay) { lockUp(); return(1); } } return(TWI_STATUS); } uint8_t I2C::stop() { unsigned long startingTime = millis(); TWCR = (1<= timeOutDelay) { lockUp(); return(1); } } return(0); } void I2C::lockUp() { TWCR = 0; //releases SDA and SCL lines to high impedance TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA); //reinitialize TWI _lockup_count++; } uint8_t I2C::lockup_count(void) { return _lockup_count; } SIGNAL(TWI_vect) { switch(TWI_STATUS) { case 0x20: case 0x30: case 0x48: TWCR = (1<