i2c.c

AVR Devolpment Board

#include "avr/io.h"
#include "compat/twi.h"

void I2C_Init(void)
{
	TWSR=0x00;
	TWBR=0x00;
	TWAR=0x00;
	TWCR=0x44;
	PORTC|=0x33;
}

unsigned char I2C_Start(void)
{
	TWCR=(1<<TWINT)|(1<<TWSTA)|(1<<TWEN);
	while(!(TWCR&(1<<TWINT)));
	return 1;
}

void I2C_Stop(void)
{
	TWCR=(1<<TWINT)|(1<<TWEN)|(1<<TWSTO);
}

unsigned char I2C_Write(unsigned char c)
{
	unsigned char ACK=1;
	TWDR=c;
	TWCR=(1<<TWINT)|(1<<TWEN);
	while(!(TWCR&(1<<TWINT)));
	if((TWSR&0xF8)!=TW_MT_SLA_ACK)
		ACK=0;
	return ACK;
}

unsigned char I2C_Read(unsigned char ACK)
{
	if(ACK)
		TWCR=(1<<TWINT)|(1<<TWEN)|(1<<TWEA);
	else
		TWCR=(1<<TWINT)|(1<<TWEN);
	while(!(TWCR&(1<<TWINT)));
	return TWDR;
}