LAUNCHXL-F28027 SPI 'SPISTE' PROBLEM

Good evening.

I am using f28027 launchpad for communicating with a DRV8301 through SPI.

The communication problem seems to be that the SPISTE pin remains always at low state even though I try to make the transition from high to low, as the DRV requires for its RX. I tried to find the register that determines this transition from the 'SPRUG71B' but I am still confused.

Can anyone explain here which register determines the SPISTE state to activate the RX state on the Slave DRV from the Master  F28027,

or post a code example which acts in this way?

My code is as follows:

          for(i=0; i<2; i++)
                 {

                  sdata = 0x1438;
                  spi_xmit(sdata);
 
                 
                   // Wait until data is received 

                 while(SpiaRegs.SPIFFRX.bit.RXFFST !=1) { }

                   // Check against sent data
                   rdata = SpiaRegs.SPIRXBUF;


                   sdata = 0x9438;
                   spi_xmit(sdata);

                   while(SpiaRegs.SPIFFRX.bit.RXFFST !=1) { }
                   rdata = SpiaRegs.SPIRXBUF;

                 }

               for(;;);

              }

void spi_init()
{
    SpiaRegs.SPICCR.all =0x4F;
    SpiaRegs.SPICTL.all =0x000E                 // Enable master mode, normal phase,
                                                 // enable talk, and SPI int disabled.
   

    SpiaRegs.SPIBRR =0x7F;
  //SpiaRegs.SPICCR.all =0x009F;                 // Relinquish SPI from Reset
    SpiaRegs.SPICCR.all =0x8F;
    SpiaRegs.SPIPRI.bit.FREE = 1;                // Set so breakpoints don't disturb xmission
}

void spi_xmit(Uint16 a)
{
    SpiaRegs.SPITXBUF=a;
}

void spi_fifo_init()
{
// Initialize SPI FIFO registers
    SpiaRegs.SPIFFTX.all=0xE040;
    SpiaRegs.SPIFFRX.all=0x2040;
    SpiaRegs.SPIFFCT.all=0x0;
}