Texas Instruments MSP430

284
USISRL = data_byte;
USICNT = (USICNT & 0xE0) + 8;
// wait until USIIFG is set
i2c_usi_mst_wait_usi_cnt_flag();
// check NACK/ACK
SET_SDA_AS_INPUT();
USICNT = (USICNT & 0xE0) + 1;
// wait for USIIFG is set
i2c_usi_mst_wait_usi_cnt_flag();
if(USISRL & 0x01)
{
// NACK received returns FALSE
return FALSE;
}
return TRUE;
}
// function to read a byte
unsigned char i2c_usi_mst_read_byte(void)
{
SET_SDA_AS_INPUT();
USICNT = (USICNT & 0xE0) + 8;
// wait for USIIFG is set
i2c_usi_mst_wait_usi_cnt_flag();
return USISRL;
}
// function to send (N)ACK bit
void i2c_usi_mst_send_n_ack(unsigned char ack)
{
// send (N)ack bit
SET_SDA_AS_OUTPUT();
if(ack)
{
USISRL = 0x00;
}
else
{
USISRL = 0xFF;
}
USICNT = (USICNT & 0xE0) + 1;
// wait until USIIFG is set
i2c_usi_mst_wait_usi_cnt_flag();
// set SDA as input
SET_SDA_AS_INPUT();
}