/** \brief Read a Byte in blocking mode and set the status.
*
* \param dev_num bsp_dev_i2c_t: I2C dev num.
* \param rx_data uint8_t*: The received byte.
* \return bsp_status_t: status of the transfer.
*
*/
bsp_status_t bsp_i2c_master_read_u8(bsp_dev_i2c_t dev_num, uint8_t* rx_data)
{
(void)dev_num;
unsigned char data;
int i;
/* Read 8 bits */
data = 0;
for(i = 0; i < 8; i++) {
set_sda_float();
i2c_sw_delay();
set_scl_float();
i2c_sw_delay();
data <<= 1;
if(get_sda())
data |= 1;
set_scl_low();
i2c_sw_delay();
}
*rx_data = data;
/* Do not Send ACK / NACK because sent by bsp_i2c_read_ack() */
return BSP_OK;
}
/** \brief Sends a Byte in blocking mode and set the status.
*
* \param dev_num bsp_dev_i2c_t: I2C dev num.
* \param tx_data uint8_t: data to send.
* \param tx_ack_flag bool*: TRUE means ACK, FALSE means NACK.
* \return bsp_status_t: status of the transfer.
*
*/
bsp_status_t bsp_i2c_master_write_u8(bsp_dev_i2c_t dev_num, uint8_t tx_data, bool* tx_ack_flag)
{
(void)dev_num;
int i;
unsigned char ack_val;
/* Write 8 bits */
for(i = 0; i < 8; i++) {
if(tx_data & 0x80)
set_sda_float();
else
set_sda_low();
i2c_sw_delay();
set_scl_float();
i2c_sw_delay();
set_scl_low();
tx_data <<= 1;
}
/* Read 1 bit ACK or NACK */
set_sda_float();
i2c_sw_delay();
set_scl_float();
i2c_sw_delay();
ack_val = get_sda();
set_scl_low();
i2c_sw_delay();
if(ack_val == 0)
*tx_ack_flag = TRUE;
else
*tx_ack_flag = FALSE;
return BSP_OK;
}
static always_inline void twi_reset(void)
{
// make sure no sda/scl remains pulled up or down
set_sda_to_input(); // deactivate internal pullup on sda/scl
set_sda_low();
set_scl_to_input();
set_scl_low();
set_sda_to_output(); // release (set high) on sda/scl
set_sda_high();
set_sda_to_input();
set_scl_to_output();
set_scl_high();
twi_reset_state();
}
/** \brief Write ACK or NACK at end of Read.
*
* \param dev_num bsp_dev_i2c_t: I2C dev num.
* \param enable_ack bool: TRUE means ACK, FALSE means NACK.
* \return void
*
*/
void bsp_i2c_read_ack(bsp_dev_i2c_t dev_num, bool enable_ack)
{
(void)dev_num;
/* Write 1 bit ACK or NACK */
if(enable_ack == TRUE)
set_sda_low(); /* ACK */
else
set_sda_float(); /* NACK */
i2c_sw_delay();
set_scl_float();
i2c_sw_delay();
set_scl_low();
}
/** \brief Sends START BIT in blocking mode and set the status.
*
* \param dev_num bsp_dev_i2c_t: I2C dev num.
* \return bsp_status_t: status of the transfer.
*
*/
bsp_status_t bsp_i2c_start(bsp_dev_i2c_t dev_num)
{
(void)dev_num;
if(i2c_started == TRUE) {
/* Re-Start condition */
set_sda_float();
i2c_sw_delay();
set_scl_float();
i2c_sw_delay();
}
/* Generate START */
/* SDA & SCL are assumed to be floating = HIGH */
set_sda_low();
i2c_sw_delay();
set_scl_low();
i2c_started = TRUE;
return BSP_OK;
}
