C28035 SPI - TX FIFO Status does not update

Hi,

I'm working with a system thas has a 28335 as a SPI master and a 28035 as SPI slave

I can't get more than the first data word sent from the slave properly.

My problem is best explained by the code fragment below, where the test of SPIFFTX.bit.TXFFST is pointless because it's always 4 when looking at it in the debugger.

I have the same construction in the 28335, where it works. The SPI blocks are set up the same, only the master/slave part is different and the 28335 uses interrupts while the 28035 does not.

Can anyone please explain why the Transmit FIFO status does not update when data is written to it?

//Pär

/* Load transmit FIFO with first data */

uiDataBlock = uiSendLength < SPI_FIFO_SIZE ? uiSendLength : SPI_FIFO_SIZE;

while( (SpibRegs.SPIFFTX.bit.TXFFST < SPI_FIFO_SIZE) && uiDataBlock )

{

    if( uiSendLength )

    {

        SpibRegs.SPITXBUF = *puiSendFrame++;

        uiSendLength--;

    }

    else

    {

        SpibRegs.SPITXBUF = 0;

    }

    uiDataBlock--;

}