CCS/TMS320F28377S: SPI with FLASH MEMORY PROBELM

Tool/software: Code Composer Studio

Hi 

I used TMS320F28377S with external flash memory SST26VF064B-104V/SM and I have a problem with ID read.

The reading procedure looks as follows:
- Master transmit 0x9F to start Read ID
-Master transmit dummy bytes 
-  Salve transmit three ID bytes
- Master read ID bytes.

I have a question  what the reading procedure should look like ?
Where I sholud write 0x9F and dummy bytes ? To  SPITxBUF or SPIDAT ?
I attach my code but it doesn't work.
In SPITXBUF, SPIRXBUF and SPIDAT I always have 0xFFFF.

Thank you for help

Best regards
Szymon

#include "F28x_Project.h"

void delay1_loop(void);
void spi_xmit(Uint16 a);
void spi_fifo_init(void);
void InitMySpi(void);
void InitSpiGpioMy();




Uint16 Flash_SpiTransmit(Uint16 Data)
{
    Uint16 i = 0;
    for (i = 0; i < 2; ++i)

    asm ("          NOP");

    SpiaRegs.SPITXBUF = Data;

    for (i = 0; i < 2; ++i)
        asm ("          NOP");

    return (Uint16) SpiaRegs.SPITXBUF;
}

Uint16 Flash_SpiReceive(Uint16 DataToTransmit)
{
    Uint16 i = 0;

    for (i = 0; i < 2; ++i)
        asm ("          NOP");

    SpiaRegs.SPIDAT = DataToTransmit;

    for (i = 0; i < 2; ++i)
        asm ("          NOP");

    return (Uint16)SpiaRegs.SPITXBUF;
}

Uint16 tab[3];
Uint16 statusRegister;
Uint16 configRegister;
Uint16 tabConfig[2];
Uint16 dataSend[256];
Uint16 dataReceive[256];

void FlashReadJedec(void)
{
    Uint16 i = 0;
    EALLOW;

    GpioDataRegs.GPACLEAR.bit.GPIO12 = 1; //CS na 0
    EDIS;
    asm ("          NOP");
    for (i = 0; i < 100; ++i)
    asm ("          NOP");
    Flash_SpiTransmit(0x9F); //command read jedec

    while(SpiaRegs.SPIFFRX.bit.RXFFST !=1) { }
    Flash_SpiReceive(0x00);
    tab[0] = SpiaRegs.SPIRXBUF;
    tab[1] = SpiaRegs.SPIRXBUF;
    tab[2] = SpiaRegs.SPIRXBUF;
    
    for (i = 0; i < 100; ++i)
    asm ("          NOP");
    EALLOW;
    GpioDataRegs.GPASET.bit.GPIO12 = 1; //CS na 1
    EDIS;
}

void main(void)
{
   InitSysCtrl();
   DINT;
   InitPieCtrl();

   IER = 0x0000;
   IFR = 0x0000;

   InitPieVectTable();

//   InitSpiaGpio();
   InitSpiGpioMy();
   InitMySpi();
   spi_fifo_init();

   while(1)
   {

       FlashReadJedec();
       Uint16 a = tab[0];
       Uint16 b = tab[1];
       Uint16 c = tab[2];

   }
}


void spi_fifo_init()
{
    SpiaRegs.SPIFFTX.all = 0xE040;
    SpiaRegs.SPIFFRX.all = 0x2044;
    SpiaRegs.SPIFFCT.all = 0x0;
}

void InitMySpi(void)
{
    SpiaRegs.SPICCR.bit.SPISWRESET = 0;
    SpiaRegs.SPICCR.bit.CLKPOLARITY = 0;
    SpiaRegs.SPICCR.bit.SPICHAR = (16-1);
    SpiaRegs.SPICCR.bit.SPILBK = 0;

    SpiaRegs.SPICTL.bit.MASTER_SLAVE = 1;
    SpiaRegs.SPICTL.bit.TALK = 1;
    SpiaRegs.SPICTL.bit.CLK_PHASE = 0;
    SpiaRegs.SPICTL.bit.SPIINTENA = 0;
    // Set the baud rate
    SpiaRegs.SPIBRR.bit.SPI_BIT_RATE = 99;
    SpiaRegs.SPIPRI.bit.FREE = 1;
    SpiaRegs.SPICCR.bit.SPISWRESET = 1;


}

void InitSpiGpioMy()
{
   EALLOW;


    GpioCtrlRegs.GPBPUD.bit.GPIO58 = 0;  //  (SPISIMOA)
    GpioCtrlRegs.GPBPUD.bit.GPIO59 = 0;  //  (SPISOMIA)
    GpioCtrlRegs.GPBPUD.bit.GPIO60 = 0;  //  (SPICLKA)

    GpioCtrlRegs.GPBQSEL2.bit.GPIO58 = 3; //  (SPISIMOA)
    GpioCtrlRegs.GPBQSEL2.bit.GPIO59 = 3; //  (SPISOMIA)
    GpioCtrlRegs.GPBQSEL2.bit.GPIO60 = 3; //  (SPICLKA)

    GpioCtrlRegs.GPBMUX2.bit.GPIO58 = 3; // SPISIMOA
    GpioCtrlRegs.GPBMUX2.bit.GPIO59 = 3; //  SPISOMIA
    GpioCtrlRegs.GPBMUX2.bit.GPIO60 = 3; // SPICLKA

    GpioCtrlRegs.GPBGMUX2.bit.GPIO58 = 3; // SPISIMOA
    GpioCtrlRegs.GPBGMUX2.bit.GPIO59 = 3; // SPISOMIA
    GpioCtrlRegs.GPBGMUX2.bit.GPIO60 = 3; //  SPICLKA

    GpioCtrlRegs.GPAMUX1.bit.GPIO12 = 0;
    GpioCtrlRegs.GPADIR.bit.GPIO12 = 1;   // CS
    GpioDataRegs.GPASET.bit.GPIO12 = 1;

    GpioCtrlRegs.GPAMUX1.bit.GPIO13 = 0;
    GpioCtrlRegs.GPADIR.bit.GPIO13 = 1;   // WP
    GpioDataRegs.GPASET.bit.GPIO13 = 1;

    GpioCtrlRegs.GPAMUX1.bit.GPIO14 = 0;
    GpioCtrlRegs.GPADIR.bit.GPIO14 = 1;   // Hold
    GpioDataRegs.GPASET.bit.GPIO14 = 1;

    EDIS;
}