Posted on May 17, 2011 at 12:08I used upsd3354D with TC72(Microchip) , the SPITXD and SPICLK works well. But, I can't READ any byte from the slave device, the SPIRXD keeps high all the time.
e.g. Read the TC72 ID (0x54), but I read 0xFF.
unsigned char ReadTemperID(void)
{ unsigned char t_id;
P1_7=1;
while (SPISTAT & SPI_BUSY_FLAG); //Waiting if SPI is busy
SPICON0|=RE;
while (!(SPISTAT & SPI_TI_FLAG)); //Waiting if SPI transfer is full
SPITDR=0x00; //Send 0x02 to select temper MSB byte
while (!(SPISTAT & SPI_TRANSMIT_END_FLAG));
while (!(SPISTAT & SPI_RI_FLAG));
SPITDR=SPI_Dummy; //Provide read clock by sending a dummy byte
while (!(SPISTAT & SPI_TRANSMIT_END_FLAG)); //Waiting if SPI transfer is full
while (!(SPISTAT & SPI_RI_FLAG)); //Waiting if SPI receiver is empty
t_id=SPIRDR; //Read data from SPIRDR register
SPICON0&=(~RE); //Disable SPI receiver
P1_7=0;
return(t_id); //Return data received
}
