TMS320F28377S: SPI reading data error

Hi, 

I'm trying to communicate the TMS320F28377xS with the DDS AD9833. The MCU works as a master and the DDS as a slave. I only need to send data, therefore I'm using a 3-wire SPI.

When I look at the Oscilloscope, seems to be fine, I can see the correct data been transfered on the falling edge. (Figure bellow. Data 0x5893 (CH2) being transfered on the falling edge, CH1 = SCLK, CH3 = EN).

However, when I transmit this to the DDS I don't get the expected result. So I tried to analyze the waveforms with the Picoscope. Here is the result:

It seems like I'm always missing the last bit (LSB).

Does anyone have any idea how can I fix this?

Here is my actual code:

/**
 * main.c
 */

#include "Peripheral_Setup.h"
#include "math.h"
#include <stdint.h>


Uint32 count = 0;
Uint16 data_vector[] = {0x2100, 0x4010, 0x5893, 0xC000, 0x2000};  //Sine - I need 5 writes to get the sine on DDS output
Uint16 rdata;
Uint16* ptr = data_vector;
Uint16 flag = 0;

void spi_xmit(Uint16 a);    
void spi_fifo_init(void);
void spi_init(void);


int main(void)
{
    //Initializations

    InitSysCtrl();      // Initialize System Control:
    InitGpio();
    //InitSpiaGpio();

    EALLOW;
    CpuSysRegs.PCLKCR0.bit.CPUTIMER0 = 1;
    EDIS;

    DINT;                                   // Disable CPU interrupts
    InitPieCtrl();                          // Initialize the PIE control registers to their default state
    IER = 0x0000;                           // Disable CPU interrupts
    IFR = 0x0000;                           // Clear all CPU interrupt flags:
    InitPieVectTable();                     // Initialize the PIE vector table

    //Functions

    Setup_GPIO();
    Setup_ePWM();
    Setup_ADC();
    spi_init();          //Initialize the SPI
    spi_fifo_init();     //Initialize the SPI FIFO

    EALLOW;
    PieVectTable.TIMER0_INT = &isr_cpu_timer0;
    //PieVectTable.ADCA1_INT = &isr_adc;
    PieCtrlRegs.PIEIER1.bit.INTx7 = 1;      //Timer 0
    //PieCtrlRegs.PIEIER1.bit.INTx1 = 1;      //ADC

    EDIS;
    IER |= M_INT1;

    InitCpuTimers();
    ConfigCpuTimer(&CpuTimer0, 200, 0.5);   //Not being used
    CpuTimer0Regs.TCR.all = 0x4001;

    EINT;                                   // Enable Global interrupt INTM
    ERTM;                                   // Enable Global realtime interrupt DBGM

    //Infinit Loop
    while(1){
        if(flag !=1){
        spi_xmit(ptr[count]);

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

        }

        if(count>4){count = 0; flag = 1;}   //After the 5 writing, no data is transfered anymore


    }

	return 0;
}

__interrupt void isr_cpu_timer0(void){
    //Not being used
    PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;

}

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

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

My SPI is configured as follow:

void spi_init(void){
    EALLOW;

    SpiaRegs.SPICCR.all =0x00DF;    
    SpiaRegs.SPICTL.all =0x001E;  
    SpiaRegs.SPIBRR.all =49;        //Baud rate = 1MHz
    SpiaRegs.SPIPRI.bit.FREE = 1;   
    EDIS;
}

Thanks in advance!