/*
* sending one bit
*/
void SkI2cSndBit(
SK_IOC IoC, /* I/O Context */
SK_U8 Bit) /* Bit to send */
{
I2C_DATA_OUT(IoC);
if (Bit) {
I2C_DATA_HIGH(IoC);
} else {
I2C_DATA_LOW(IoC);
}
SkDgWaitTime(IoC, NS2BCLK(T_DATA_IN_SETUP));
I2C_CLK_HIGH(IoC);
SkDgWaitTime(IoC, NS2BCLK(T_CLK_HIGH));
I2C_CLK_LOW(IoC);
} /* SkI2cSndBit*/
/** \brief This I2C function generates a Wake-up pulse and delays.
* \return status of the operation
*/
uint8_t ecc108p_wakeup(void)
{
#if !defined(ECC108_GPIO_WAKEUP) && !defined(ECC108_I2C_BITBANG)
// Generate wakeup pulse by writing a 0 on the I2C bus.
uint8_t dummy_byte = 0;
uint8_t i2c_status = i2c_send_start();
if (i2c_status != I2C_FUNCTION_RETCODE_SUCCESS)
return ECC108_COMM_FAIL;
// To send eight zero bits it takes 10E6 / I2C clock * 8 us.
delay_10us(ECC108_WAKEUP_PULSE_WIDTH - (uint8_t) (1000000.0 / 10.0 / I2C_CLOCK * 8.0));
// We have to send at least one byte between an I2C Start and an I2C Stop.
(void) i2c_send_bytes(1, &dummy_byte);
i2c_status = i2c_send_stop();
if (i2c_status != I2C_FUNCTION_RETCODE_SUCCESS)
return ECC108_COMM_FAIL;
#else
# if defined(ECC108_I2C_BITBANG)
// Generate wakeup pulse using the GPIO pin that is connected to SDA.
I2C_DATA_LOW();
delay_10us(ECC108_WAKEUP_PULSE_WIDTH);
I2C_DATA_HIGH();
# else
// Generate wakeup pulse by disabling the I2C peripheral and
// pulling SDA low. The I2C peripheral gets automatically
// re-enabled when calling i2c_send_start().
// PORTD is used on the Microbase. You might have to use another
// port for a different target.
TWCR = 0; // Disable I2C.
//DDRD |= _BV(PD1); // Set SDA as output.
//PORTD &= ~_BV(PD1); // Set SDA low.
pinMode(SDA, OUTPUT);
digitalWrite(SDA, LOW);
delay_10us(ECC108_WAKEUP_PULSE_WIDTH);
//PORTD |= _BV(PD1); // Set SDA high.
digitalWrite(SDA, HIGH);
# endif
#endif
delay_10us(ECC108_WAKEUP_DELAY);
return ECC108_SUCCESS;
}
/*
* Signal a start to the I2C Bus.
*
* A start is signaled when data goes to low in a high clock cycle.
*
* Ends with Clock Low.
*
* Status: not tested
*/
void SkI2cStart(
SK_IOC IoC) /* I/O Context */
{
/* Init data and Clock to output lines */
/* Set Data high */
I2C_DATA_OUT(IoC);
I2C_DATA_HIGH(IoC);
/* Set Clock high */
I2C_CLK_HIGH(IoC);
SkDgWaitTime(IoC, NS2BCLK(T_START_SETUP));
/* Set Data Low */
I2C_DATA_LOW(IoC);
SkDgWaitTime(IoC, NS2BCLK(T_START_HOLD));
/* Clock low without Data to Input */
I2C_START_COND(IoC);
SkDgWaitTime(IoC, NS2BCLK(T_CLK_LOW));
} /* SkI2cStart */
