/*
* This function reads one byte from the slave device
*
* Parameters:
* ack - Flag to indicate either to send the acknowledge
* message to the slave device or not
*
* Return Value:
* One byte data read from the Slave device
*/
static unsigned char swI2CReadByte(unsigned char ack)
{
int i;
unsigned char data = 0;
for(i=7; i>=0; i--)
{
/* Set the SCL to Low and SDA to High (Input) */
swI2CSCL(0);
swI2CSDA(1);
swI2CWait();
/* Set the SCL High */
swI2CSCL(1);
swI2CWait();
/* Read data bits from SDA */
data |= (swI2CReadSDA() << i);
}
if (ack)
swI2CAck();
/* Set the SCL Low and SDA High */
swI2CSCL(0);
swI2CSDA(1);
return data;
}
/*
* This function sends the start command to the slave device
*/
static void swI2CStart(void)
{
/* Start I2C */
swI2CSDA(1);
swI2CSCL(1);
swI2CSDA(0);
}
/*
* This function sends the stop command to the slave device
*/
static void swI2CStop(void)
{
/* Stop the I2C */
swI2CSCL(1);
swI2CSDA(0);
swI2CSDA(1);
}
/*******************************************************************************
swI2CStop
This function sends the stop command to the slave device
Parameters:
None
Return value:
None
*******************************************************************************/
void swI2CStop()
{
/* Stop the I2C */
swI2CSCL(1);
swI2CSDA(0);
swI2CSDA(1);
}
/*
* This function writes one byte to the slave device
*
* Parameters:
* data - Data to be write to the slave device
*
* Return Value:
* 0 - Success
* -1 - Fail to write byte
*/
static long swI2CWriteByte(unsigned char data)
{
unsigned char value = data;
int i;
/* Sending the data bit by bit */
for (i=0; i<8; i++)
{
/* Set SCL to low */
swI2CSCL(0);
/* Send data bit */
if ((value & 0x80) != 0)
swI2CSDA(1);
else
swI2CSDA(0);
swI2CWait();
/* Toggle clk line to one */
swI2CSCL(1);
swI2CWait();
/* Shift byte to be sent */
value = value << 1;
}
/* Set the SCL Low and SDA High (prepare to get input) */
swI2CSCL(0);
swI2CSDA(1);
/* Set the SCL High for ack */
swI2CWait();
swI2CSCL(1);
swI2CWait();
/* Read SDA, until SDA==0 */
for(i=0; i<0xff; i++)
{
if (!swI2CReadSDA())
break;
swI2CSCL(0);
swI2CWait();
swI2CSCL(1);
swI2CWait();
}
/* Set the SCL Low and SDA High */
swI2CSCL(0);
swI2CSDA(1);
if (i<0xff)
return 0;
else
return -1;
}
