/**************************
* File name: i2c.h
* I2C drivers in C51 
**************************/

#ifndef _I2C_H
#define _I2C_H

#define I2C_DELAY 0x0F /* For delay i2c bus */

void I2C_delay(void)
{
	unsigned char i;
	for(i=0; i<I2C_DELAY; i++);
}

void I2C_clock(void)
{
	I2C_delay();
	SCL = 1; /* Start clock */
	I2C_delay();
	SCL = 0; /* Clear SCL */
}

void I2C_start(void)
{
	if(SCL)
	SCL = 0; /* Clear SCL */
	SDA = 1; /* Set SDA */
	SCL = 1; /* Set SCL */
	I2C_delay();
	SDA = 0; /* Clear SDA */
	I2C_delay();
	SCL = 0; /* Clear SCL */
}

void I2C_stop(void)
{
	if(SCL)
	SCL = 0; /* Clear SCL */
	SDA = 0; /* Clear SDA */
	I2C_delay();
	SCL = 1; /* Set SCL */
	I2C_delay();
	SDA = 1; /* Set SDA */
}

bit I2C_write(unsigned char dat)
{
	bit data_bit;
	unsigned char i;
	for(i=0;i<8;i++) /* For loop 8 time(send data 1 byte) */
	{
		data_bit = dat & 0x80; /* Filter MSB bit keep to data_bit */
		SDA = data_bit; /* Send data_bit to SDA */
		I2C_clock();       /* Call for send data to i2c bus */
		dat = dat<<1;
	}
	SDA = 1; /* Set SDA */
	I2C_delay();
	SCL = 1; /* Set SCL */
	I2C_delay();
	data_bit = SDA;   /* Check acknowledge */
	SCL = 0; /* Clear SCL */
	I2C_delay();
	return data_bit; /* If send_bit = 0 i2c is valid */
}

unsigned char I2C_read(void)
{
	bit rd_bit;
	unsigned char i, dat;
	dat = 0x00;
	for(i=0;i<8;i++) /* For loop read data 1 byte */
	{
		I2C_delay();
		SCL = 1; /* Set SCL */
		I2C_delay();
		rd_bit = SDA; /* Keep for check acknowledge */
		dat = dat<<1;
		dat = dat | rd_bit; /* Keep bit data in dat */
		SCL = 0; /* Clear SCL */
	}
	return dat;
}

void I2C_ack()
{
	SDA = 0; /* Clear SDA */
	I2C_delay();
	I2C_clock(); /* Call for send data to i2c bus */
	SDA = 1; /* Set SDA */
}

void I2C_noack()
{
	SDA = 1; /* Set SDA */
	I2C_delay();
	I2C_clock(); /* Call for send data to i2c bus */
	SCL = 1; /* Set SCL */
}
#endif