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I2C.h
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/*
I2C.h - 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>
#ifndef I2C_h
#define I2C_h
#define START 0x08
#define REPEATED_START 0x10
#define MT_SLA_ACK 0x18
#define MT_SLA_NACK 0x20
#define MT_DATA_ACK 0x28
#define MT_DATA_NACK 0x30
#define MR_SLA_ACK 0x40
#define MR_SLA_NACK 0x48
#define MR_DATA_ACK 0x50
#define MR_DATA_NACK 0x58
#define LOST_ARBTRTN 0x38
#define TWI_STATUS (TWSR & 0xF8)
#define SLA_W(address) (address << 1)
#define SLA_R(address) ((address << 1) + 0x01)
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#define MAX_BUFFER_SIZE 32
class I2C
{
public:
I2C();
void begin();
void end();
void timeOut(uint16_t);
void setSpeed(uint8_t);
void pullup(uint8_t);
void scan();
uint8_t available();
uint8_t receive();
uint8_t write(uint8_t, uint8_t);
uint8_t write(int, int);
uint8_t write(uint8_t, uint8_t, uint8_t);
uint8_t write(int, int, int);
uint8_t write(uint8_t, uint8_t, const char *);
uint8_t write(uint8_t, uint8_t, uint16_t); //Will write 2 bytes
uint8_t write(uint8_t, uint8_t, uint32_t); //Will write 4 bytes
uint8_t write(uint8_t, uint8_t, uint64_t); //Will write 8 bytes
uint8_t write(uint8_t, uint8_t, const uint8_t *, uint8_t);
uint8_t read(uint8_t, uint8_t);
uint8_t read(int, int);
uint8_t read(uint8_t, uint8_t, uint8_t);
uint8_t read(int, int, int);
uint8_t read(uint8_t, uint8_t, uint8_t *);
uint8_t read(uint8_t, uint8_t, uint8_t, uint8_t *);
//These functions will be used to write to Slaves that take 16-bit addresses
uint8_t write16(uint8_t, uint16_t);
uint8_t write16(uint8_t, uint16_t, uint8_t);
uint8_t write16(uint8_t, uint16_t, const char *);
uint8_t write16(uint8_t, uint16_t, uint16_t); //Will write 2 bytes
uint8_t write16(uint8_t, uint16_t, uint32_t); //Will write 4 bytes
uint8_t write16(uint8_t, uint16_t, uint64_t); //Will write 8 bytes
uint8_t write16(uint8_t, uint16_t, const uint8_t *, uint8_t);
//These functions will be used to read from Slaves that take 16-bit addresses
uint8_t read16(uint8_t, uint16_t, uint8_t);
uint8_t read16(uint8_t, uint16_t, uint8_t, uint8_t *);
//Low-level methods
uint8_t _start();
uint8_t _sendAddress(uint8_t);
uint8_t _sendByte(uint8_t);
uint8_t _receiveByte(uint8_t);
uint8_t _receiveByte(uint8_t, uint8_t *target);
uint8_t _stop();
private:
void lockUp();
uint8_t returnStatus;
uint8_t nack;
uint8_t data[MAX_BUFFER_SIZE];
static uint8_t bytesAvailable;
static uint8_t bufferIndex;
static uint8_t totalBytes;
static uint16_t timeOutDelay;
};
extern I2C I2c;
#endif