static uint8_t I2CGetByte(uint8_t lastbyte, uint8_t * Data)
{
uint8_t abyte = 0;
uint8_t i;
for (i = 0; i < 8; i++) //get each bit, MSB first
{
if (SetSCLHigh())
return IIC_SCL_TIMEOUT;
abyte <<= 1; //shift result over to make room for next bit
if (GET_SDA())
abyte++; //same as 'abyte |= 1', only faster
CLEAR_SCL();
}
if (lastbyte)
SET_SDA(); //do not ACK last uint8_t read
else
CLEAR_SDA();
if (SetSCLHigh())
return IIC_SCL_TIMEOUT;
CLEAR_SCL();
SET_SDA();
*Data = abyte;
return IIC_OK;
}
static uint8_t i2c_soft_receive_bit(void)
{
// SDA = 1
// SCL = 1
// wait SCL low
// bit = SDA
// SCL = 0
uint8_t bit;
SDA(1);
waitSomeTimeInUs(1);
SCL1();
waitSomeTimeInUs(1);
while( GET_SCL() == 0);
bit = GET_SDA();
SCL0();
SDA_OUTPUT();
waitSomeTimeInUs(1);
return bit;
}
/*---------------------------------------------------
int i2c_gpio_phase_start();
Generate i2c_gpio_phase_start Condition:
Stream Format:
SCL _____/--------\___
SDA =---------\_____
width (4.7u)4.7u|4.7u|
Arguments:
NONE
Return value:
int SUCCESS 0
int ERR_STATUS 1
----------------------------------------------------*/
static RET_CODE i2c_gpio_phase_start(i2c_gpio_priv_t *p_priv)
{
/* Make sure is out */
SET_SDA_OUT(p_priv);
SET_SCL_OUT(p_priv);
SET_SDA_HI(p_priv); /* Set SDA high */
if(0 == GET_SCL(p_priv))
{
I2C_GPIO_DELAY_US(p_priv->clock_period);
}
SET_SCL_HI(p_priv); /* Set SCL high */
I2C_GPIO_DELAY_US(p_priv->clock_period);
if(0 == GET_SCL(p_priv))
{
return ERR_STATUS;
}
if(0 == GET_SDA(p_priv))
{
return ERR_STATUS;
}
SET_SDA_LO(p_priv);
I2C_GPIO_DELAY_US(p_priv->clock_period);
SET_SCL_LO(p_priv);
return SUCCESS;
}
//------------------------------------------------------------------------------
// Function: SendByte
// Description:
//------------------------------------------------------------------------------
static uint8_t I2CSendByte(uint8_t abyte)
{
uint8_t error = 0;
uint8_t i;
for (i = 0; i < 8; i++)
{
if (abyte & 0x80)
SET_SDA(); //send each bit, MSB first
else
CLEAR_SDA();
if (SetSCLHigh()) //do clock cycle
return IIC_SCL_TIMEOUT;
CLEAR_SCL();
abyte <<= 1; //shift over to get next bit
}
SET_SDA(); //listen for ACK
#if 1
if (SetSCLHigh())
return IIC_SCL_TIMEOUT;
if (GET_SDA()) //error if no ACK
{
printk("IIC_NOACK\n");
error = IIC_NOACK;
}
#endif
CLEAR_SCL();
return (error); //return 0 for no ACK, 1 for ACK received
}
/*---------------------------------------------------
int i2c_gpio_phase_get_bit(id);
Set a BIT (Hi or Low)
Stream Format:
SCL _____/---\
SDA ??AAAAAAAA
width 4.7u| 4u|
Arguments:
NONE
Return value:
int i : Set(1) or Clear(0) this bit on iic bus
----------------------------------------------------*/
static int i2c_gpio_phase_get_bit(i2c_gpio_priv_t *p_priv)
{
int ret = 0;
SET_SDA_IN(p_priv);
SET_SDA_HI(p_priv); /* Hi Ind */
I2C_GPIO_DELAY_US(p_priv->clock_period);
SET_SCL_HI(p_priv);
I2C_GPIO_DELAY_US(p_priv->clock_period);
ret = GET_SDA(p_priv);
SET_SCL_LO(p_priv);
return ret;
}