You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
728 lines
17 KiB
728 lines
17 KiB
/*
|
|
I2C.cpp - I2C library
|
|
Copyright (c) 2011-2012 Wayne Truchsess. All right reserved.
|
|
Rev 5.0 - January 24th, 2012
|
|
- Removed the use of interrupts completely from the library
|
|
so TWI state changes are now polled.
|
|
- Added calls to lockup() function in most functions
|
|
to combat arbitration problems
|
|
- Fixed scan() procedure which left timeouts enabled
|
|
and set to 80msec after exiting procedure
|
|
- Changed scan() address range back to 0 - 0x7F
|
|
- Removed all Wire legacy functions from library
|
|
- A big thanks to Richard Baldwin for all the testing
|
|
and feedback with debugging bus lockups!
|
|
Rev 4.0 - January 14th, 2012
|
|
- Updated to make compatible with 8MHz clock frequency
|
|
Rev 3.0 - January 9th, 2012
|
|
- Modified library to be compatible with Arduino 1.0
|
|
- Changed argument type from boolean to uint8_t in pullUp(),
|
|
setSpeed() and receiveByte() functions for 1.0 compatability
|
|
- Modified return values for timeout feature to report
|
|
back where in the transmission the timeout occured.
|
|
- added function scan() to perform a bus scan to find devices
|
|
attached to the I2C bus. Similar to work done by Todbot
|
|
and Nick Gammon
|
|
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
|
|
*/
|
|
|
|
#if(ARDUINO >= 100)
|
|
#include <Arduino.h>
|
|
#else
|
|
#include <WProgram.h>
|
|
#endif
|
|
|
|
#include <inttypes.h>
|
|
#include "Lib_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 = ((F_CPU / 100000) - 16) / 2;
|
|
// enable twi module and acks
|
|
TWCR = _BV(TWEN) | _BV(TWEA);
|
|
}
|
|
|
|
void I2C::end()
|
|
{
|
|
TWCR = 0;
|
|
}
|
|
|
|
void I2C::timeOut(uint16_t _timeOut)
|
|
{
|
|
timeOutDelay = _timeOut;
|
|
}
|
|
|
|
void I2C::setSpeed(uint8_t _fast)
|
|
{
|
|
if(!_fast)
|
|
{
|
|
TWBR = ((F_CPU / 100000) - 16) / 2;
|
|
}
|
|
else
|
|
{
|
|
TWBR = ((F_CPU / 400000) - 16) / 2;
|
|
}
|
|
}
|
|
|
|
void I2C::pullup(uint8_t 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
|
|
}
|
|
}
|
|
|
|
void I2C::scan()
|
|
{
|
|
uint16_t tempTime = timeOutDelay;
|
|
timeOut(80);
|
|
uint8_t totalDevicesFound = 0;
|
|
Serial.println(F("Scanning for devices...please wait"));
|
|
Serial.println();
|
|
for(uint8_t s = 0; s <= 0x7F; s++)
|
|
{
|
|
returnStatus = 0;
|
|
returnStatus = start();
|
|
if(!returnStatus)
|
|
{
|
|
returnStatus = sendAddress(SLA_W(s));
|
|
}
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1)
|
|
{
|
|
Serial.println(F("There is a problem with the bus, could not complete scan"));
|
|
timeOutDelay = tempTime;
|
|
return;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
Serial.print(F("Found device at address - "));
|
|
Serial.print(F(" 0x"));
|
|
Serial.println(s,HEX);
|
|
totalDevicesFound++;
|
|
}
|
|
stop();
|
|
}
|
|
if(!totalDevicesFound){Serial.println(F("No devices found"));}
|
|
timeOutDelay = tempTime;
|
|
}
|
|
|
|
|
|
uint8_t I2C::available()
|
|
{
|
|
return(bytesAvailable);
|
|
}
|
|
|
|
uint8_t I2C::receive()
|
|
{
|
|
bufferIndex = totalBytes - bytesAvailable;
|
|
if(!bytesAvailable)
|
|
{
|
|
bufferIndex = 0;
|
|
return(0);
|
|
}
|
|
bytesAvailable--;
|
|
return(data[bufferIndex]);
|
|
}
|
|
|
|
/*return values for new functions that use the timeOut feature
|
|
will now return at what point in the transmission the timeout
|
|
occurred. Looking at a full communication sequence between a
|
|
master and slave (transmit data and then readback data) there
|
|
a total of 7 points in the sequence where a timeout can occur.
|
|
These are listed below and correspond to the returned value:
|
|
1 - Waiting for successful completion of a Start bit
|
|
2 - Waiting for ACK/NACK while addressing slave in transmit mode (MT)
|
|
3 - Waiting for ACK/NACK while sending data to the slave
|
|
4 - Waiting for successful completion of a Repeated Start
|
|
5 - Waiting for ACK/NACK while addressing slave in receiver mode (MR)
|
|
6 - Waiting for ACK/NACK while receiving data from the slave
|
|
7 - Waiting for successful completion of the Stop bit
|
|
|
|
All possible return values:
|
|
0 Function executed with no errors
|
|
1 - 7 Timeout occurred, see above list
|
|
8 - 0xFF See datasheet for exact meaning */
|
|
|
|
/////////////////////////////////////////////////////
|
|
|
|
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)
|
|
{
|
|
if(returnStatus == 1){return(2);}
|
|
return(returnStatus);
|
|
}
|
|
returnStatus = sendByte(registerAddress);
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(3);}
|
|
return(returnStatus);
|
|
}
|
|
returnStatus = stop();
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(7);}
|
|
return(returnStatus);
|
|
}
|
|
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 data)
|
|
{
|
|
returnStatus = 0;
|
|
returnStatus = start();
|
|
if(returnStatus){return(returnStatus);}
|
|
returnStatus = sendAddress(SLA_W(address));
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(2);}
|
|
return(returnStatus);
|
|
}
|
|
returnStatus = sendByte(registerAddress);
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(3);}
|
|
return(returnStatus);
|
|
}
|
|
returnStatus = sendByte(data);
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(3);}
|
|
return(returnStatus);
|
|
}
|
|
returnStatus = stop();
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(7);}
|
|
return(returnStatus);
|
|
}
|
|
return(returnStatus);
|
|
}
|
|
|
|
uint8_t I2C::write(int address, int registerAddress, int data)
|
|
{
|
|
return(write((uint8_t) address, (uint8_t) registerAddress, (uint8_t) data));
|
|
}
|
|
|
|
uint8_t I2C::write(uint8_t address, uint8_t registerAddress, char *data)
|
|
{
|
|
uint8_t bufferLength = strlen(data);
|
|
returnStatus = 0;
|
|
returnStatus = write(address, registerAddress, (uint8_t*)data, bufferLength);
|
|
return(returnStatus);
|
|
}
|
|
|
|
uint8_t I2C::write(uint8_t address, uint8_t registerAddress, uint8_t *data, uint8_t numberBytes)
|
|
{
|
|
returnStatus = 0;
|
|
returnStatus = start();
|
|
if(returnStatus){return(returnStatus);}
|
|
returnStatus = sendAddress(SLA_W(address));
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(2);}
|
|
return(returnStatus);
|
|
}
|
|
returnStatus = sendByte(registerAddress);
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(3);}
|
|
return(returnStatus);
|
|
}
|
|
for (uint8_t i = 0; i < numberBytes; i++)
|
|
{
|
|
returnStatus = sendByte(data[i]);
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(3);}
|
|
return(returnStatus);
|
|
}
|
|
}
|
|
returnStatus = stop();
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(7);}
|
|
return(returnStatus);
|
|
}
|
|
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)
|
|
{
|
|
if(returnStatus == 1){return(5);}
|
|
return(returnStatus);
|
|
}
|
|
for(uint8_t i = 0; i < numberBytes; i++)
|
|
{
|
|
if( i == nack )
|
|
{
|
|
returnStatus = receiveByte(0);
|
|
if(returnStatus == 1){return(6);}
|
|
|
|
if(returnStatus != MR_DATA_NACK){return(returnStatus);}
|
|
}
|
|
else
|
|
{
|
|
returnStatus = receiveByte(1);
|
|
if(returnStatus == 1){return(6);}
|
|
if(returnStatus != MR_DATA_ACK){return(returnStatus);}
|
|
}
|
|
data[i] = TWDR;
|
|
bytesAvailable = i+1;
|
|
totalBytes = i+1;
|
|
}
|
|
returnStatus = stop();
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(7);}
|
|
return(returnStatus);
|
|
}
|
|
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)
|
|
{
|
|
if(returnStatus == 1){return(2);}
|
|
return(returnStatus);
|
|
}
|
|
returnStatus = sendByte(registerAddress);
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(3);}
|
|
return(returnStatus);
|
|
}
|
|
returnStatus = start();
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(4);}
|
|
return(returnStatus);
|
|
}
|
|
returnStatus = sendAddress(SLA_R(address));
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(5);}
|
|
return(returnStatus);
|
|
}
|
|
for(uint8_t i = 0; i < numberBytes; i++)
|
|
{
|
|
if( i == nack )
|
|
{
|
|
returnStatus = receiveByte(0);
|
|
if(returnStatus == 1){return(6);}
|
|
if(returnStatus != MR_DATA_NACK){return(returnStatus);}
|
|
}
|
|
else
|
|
{
|
|
returnStatus = receiveByte(1);
|
|
if(returnStatus == 1){return(6);}
|
|
if(returnStatus != MR_DATA_ACK){return(returnStatus);}
|
|
}
|
|
data[i] = TWDR;
|
|
bytesAvailable = i+1;
|
|
totalBytes = i+1;
|
|
}
|
|
returnStatus = stop();
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(7);}
|
|
return(returnStatus);
|
|
}
|
|
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)
|
|
{
|
|
if(returnStatus == 1){return(5);}
|
|
return(returnStatus);
|
|
}
|
|
for(uint8_t i = 0; i < numberBytes; i++)
|
|
{
|
|
if( i == nack )
|
|
{
|
|
returnStatus = receiveByte(0);
|
|
if(returnStatus == 1){return(6);}
|
|
if(returnStatus != MR_DATA_NACK){return(returnStatus);}
|
|
}
|
|
else
|
|
{
|
|
returnStatus = receiveByte(1);
|
|
if(returnStatus == 1){return(6);}
|
|
if(returnStatus != MR_DATA_ACK){return(returnStatus);}
|
|
}
|
|
dataBuffer[i] = TWDR;
|
|
bytesAvailable = i+1;
|
|
totalBytes = i+1;
|
|
}
|
|
returnStatus = stop();
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(7);}
|
|
return(returnStatus);
|
|
}
|
|
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){return(returnStatus);}
|
|
returnStatus = sendAddress(SLA_W(address));
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(2);}
|
|
return(returnStatus);
|
|
}
|
|
returnStatus = sendByte(registerAddress);
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(3);}
|
|
return(returnStatus);
|
|
}
|
|
returnStatus = start();
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(4);}
|
|
return(returnStatus);
|
|
}
|
|
returnStatus = sendAddress(SLA_R(address));
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(5);}
|
|
return(returnStatus);
|
|
}
|
|
for(uint8_t i = 0; i < numberBytes; i++)
|
|
{
|
|
if( i == nack )
|
|
{
|
|
returnStatus = receiveByte(0);
|
|
if(returnStatus == 1){return(6);}
|
|
if(returnStatus != MR_DATA_NACK){return(returnStatus);}
|
|
}
|
|
else
|
|
{
|
|
returnStatus = receiveByte(1);
|
|
if(returnStatus == 1){return(6);}
|
|
if(returnStatus != MR_DATA_ACK){return(returnStatus);}
|
|
}
|
|
dataBuffer[i] = TWDR;
|
|
bytesAvailable = i+1;
|
|
totalBytes = i+1;
|
|
}
|
|
returnStatus = stop();
|
|
if(returnStatus)
|
|
{
|
|
if(returnStatus == 1){return(7);}
|
|
return(returnStatus);
|
|
}
|
|
return(returnStatus);
|
|
}
|
|
|
|
/////////////// Private Methods ////////////////////////////////////////
|
|
|
|
uint8_t I2C::start()
|
|
{
|
|
unsigned long startingTime = millis();
|
|
TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
|
|
while (!(TWCR & (1 << TWINT)))
|
|
{
|
|
if(!timeOutDelay){continue;}
|
|
if((millis() - startingTime) >= timeOutDelay)
|
|
{
|
|
lockUp();
|
|
return(1);
|
|
}
|
|
|
|
}
|
|
if ((TWI_STATUS == START) || (TWI_STATUS == REPEATED_START))
|
|
{
|
|
return(0);
|
|
}
|
|
if (TWI_STATUS == LOST_ARBTRTN)
|
|
{
|
|
uint8_t bufferedStatus = TWI_STATUS;
|
|
lockUp();
|
|
return(bufferedStatus);
|
|
}
|
|
return(TWI_STATUS);
|
|
}
|
|
|
|
uint8_t I2C::sendAddress(uint8_t i2cAddress)
|
|
{
|
|
TWDR = i2cAddress;
|
|
unsigned long startingTime = millis();
|
|
TWCR = (1 << TWINT) | (1 << TWEN);
|
|
while (!(TWCR & (1 << TWINT)))
|
|
{
|
|
if(!timeOutDelay){continue;}
|
|
if((millis() - startingTime) >= timeOutDelay)
|
|
{
|
|
lockUp();
|
|
return(1);
|
|
}
|
|
|
|
}
|
|
if ((TWI_STATUS == MT_SLA_ACK) || (TWI_STATUS == MR_SLA_ACK))
|
|
{
|
|
return(0);
|
|
}
|
|
uint8_t bufferedStatus = TWI_STATUS;
|
|
if ((TWI_STATUS == MT_SLA_NACK) || (TWI_STATUS == MR_SLA_NACK))
|
|
{
|
|
stop();
|
|
return(bufferedStatus);
|
|
}
|
|
else
|
|
{
|
|
lockUp();
|
|
return(bufferedStatus);
|
|
}
|
|
}
|
|
|
|
uint8_t I2C::sendByte(uint8_t i2cData)
|
|
{
|
|
TWDR = i2cData;
|
|
unsigned long startingTime = millis();
|
|
TWCR = (1 << TWINT) | (1 << TWEN);
|
|
while (!(TWCR & (1 << TWINT)))
|
|
{
|
|
if(!timeOutDelay){continue;}
|
|
if((millis() - startingTime) >= timeOutDelay)
|
|
{
|
|
lockUp();
|
|
return(1);
|
|
}
|
|
|
|
}
|
|
if (TWI_STATUS == MT_DATA_ACK)
|
|
{
|
|
return(0);
|
|
}
|
|
uint8_t bufferedStatus = TWI_STATUS;
|
|
if (TWI_STATUS == MT_DATA_NACK)
|
|
{
|
|
stop();
|
|
return(bufferedStatus);
|
|
}
|
|
else
|
|
{
|
|
lockUp();
|
|
return(bufferedStatus);
|
|
}
|
|
}
|
|
|
|
uint8_t I2C::receiveByte(uint8_t ack)
|
|
{
|
|
unsigned long startingTime = millis();
|
|
if(ack)
|
|
{
|
|
TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
|
|
|
|
}
|
|
else
|
|
{
|
|
TWCR = (1 << TWINT) | (1 << TWEN);
|
|
}
|
|
while (!(TWCR & (1 << TWINT)))
|
|
{
|
|
if(!timeOutDelay){continue;}
|
|
if((millis() - startingTime) >= timeOutDelay)
|
|
{
|
|
lockUp();
|
|
return(1);
|
|
}
|
|
}
|
|
if (TWI_STATUS == LOST_ARBTRTN)
|
|
{
|
|
uint8_t bufferedStatus = TWI_STATUS;
|
|
lockUp();
|
|
return(bufferedStatus);
|
|
}
|
|
return(TWI_STATUS);
|
|
}
|
|
|
|
uint8_t I2C::receiveByte(uint8_t ack, uint8_t *target)
|
|
{
|
|
uint8_t stat = I2C::receiveByte(ack);
|
|
if (stat == 1)
|
|
{
|
|
return(6);
|
|
}
|
|
if (ack)
|
|
{
|
|
if(stat != MR_DATA_ACK)
|
|
{
|
|
*target = 0x0;
|
|
return(stat);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
if(stat != MR_DATA_NACK)
|
|
{
|
|
*target = 0x0;
|
|
return(stat);
|
|
}
|
|
}
|
|
*target = TWDR;
|
|
// I suppose that if we get this far we're ok
|
|
return 0;
|
|
}
|
|
|
|
uint8_t I2C::stop()
|
|
{
|
|
unsigned long startingTime = millis();
|
|
TWCR = (1 << TWINT)|(1 << TWEN)| (1 << TWSTO);
|
|
while ((TWCR & (1 << TWSTO)))
|
|
{
|
|
if(!timeOutDelay){continue;}
|
|
if((millis() - startingTime) >= timeOutDelay)
|
|
{
|
|
lockUp();
|
|
return(1);
|
|
}
|
|
|
|
}
|
|
return(0);
|
|
}
|
|
|
|
void I2C::lockUp()
|
|
{
|
|
TWCR = 0; //releases SDA and SCL lines to high impedance
|
|
TWCR = _BV(TWEN) | _BV(TWEA); //reinitialize TWI
|
|
}
|
|
|
|
I2C I2c = I2C();
|
|
|
|
|