Bit bang TWI master driver. More...

#include "ioavr.h"
#include "inavr.h"

Defines
#define	SCL PC1
	Definition of pin used as SCL.
#define	SDA PC4
	Definition of pin used as SDA.
#define	PORT_SCL PORTC
	Definition of PORT used as SCL.
#define	DDR_SCL DDRC
	Definition of DDR used as SCL.
#define	PIN_SCL PINC
	Definition of PIN used as SCL.
#define	PORT_SDA PORTC
	Definition of PORT used as SDA.
#define	DDR_SDA DDRC
	Definition of DDR used as SDA.
#define	PIN_SDA PINC
	Definition of PIN used as SDA.
#define	SLAVE_ADDRESS 0xA0
	Slave 8 bit address (shifted).
#define	READ_SDA() (PIN_SDA & (1 << SDA))
#define	SET_SDA_OUT() DDR_SDA \|= (1 << SDA)
#define	SET_SDA_IN() DDR_SDA &= ~(1 << SDA)
#define	READ_SCL() (PIN_SCL & (1 << SCL))?1:0
#define	WRITE 0x0
#define	READ 0x1
#define	DELAY 2
	Delay used to generate clock.
#define	SCL_SDA_DELAY 1
	Delay used for STOP condition.
Functions
void	twi_disable ()
	disables twi master mode
void	twi_init ()
	initialize twi master mode
void	toggle_scl ()
	Toggles SCL.
void	write_scl (char x)
	Writes SCL.
char	twi_start_cond (void)
	Sends start condition.
char	send_slave_address (unsigned char read)
	Sends slave address.
char	write_data (unsigned char *data, char bytes)
	Writes data from buffer.
char	i2c_write_byte (unsigned char byte)
	Writes a byte on TWI.
char	read_bytes (unsigned char *data, char bytes)
	Reads data into buffer.
char	i2c_read_byte (unsigned char *data, unsigned char bytes, unsigned char index)
	Reads one byte into buffer.
void	write_sda (char x)
	Writes SDA.

Detailed Description

Bit bang TWI master driver.

This file contains the function prototypes and enumerator definitions for various configuration parameters for the AVR TWI master driver.

The driver is not intended for size and/or speed critical code, since most functions are just a few lines of code, and the function call overhead would decrease code performance. The driver is intended for rapid prototyping and documentation purposes for getting started with the AVR TWI master.

For size and/or speed critical code, it is recommended to copy the function contents directly into your application instead of making a function call.

Date:: 2012-06-01 13:03:43

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. The name of ATMEL may not be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Author: gary.grewal

Function Documentation

char i2c_read_byte	(	unsigned char *	rcvdata,
		unsigned char	bytes,
		unsigned char	index
	)

Reads one byte into buffer.

Parameters:

rcvdata	Pointer to data buffer
bytes	Number of bytes to read
index	Position of the incoming byte in hte receive buffer

Returns:: 1 if successful, otherwise 0

char i2c_write_byte ( unsigned char byte )

Writes a byte on TWI.

Parameters:

byte Data

Returns:: 1 if successful, otherwise 0

char read_bytes	(	unsigned char *	data,
		char	bytes
	)

Reads data into buffer.

Parameters:

data	Pointer to data buffer
bytes	Number of bytes to read

Returns:: 1 if successful, otherwise 0

char write_data	(	unsigned char *	indata,
		char	bytes
	)

Writes data from buffer.

Parameters:

indata	Pointer to data buffer
bytes	Number of bytes to transfer

Returns:: 1 if successful, otherwise 0

void write_scl ( char x )

Writes SCL.

Parameters:

x	tristates SCL when x = 1, other wise 0

void write_sda ( char x )

Writes SDA.

Parameters:

x	tristates SDA when x = 1, other wise 0

Defines

Functions

Detailed Description

Function Documentation