Embed4u

I2C driver:

sbit SDA=P2^7; /* Set P2.7 = SDA */
sbit SCL=P2^6;
#define I2C_DELAY 0×0F /* For delay i2c bus */

void I2C_delay(void)
{
unsigned char i;

for(i=0; 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 & 0×80; /* 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 = 0×00;

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 */
}