TMS320F28069 SPI slave mode transmitting problem

#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File
#include <stdio.h>      /* printf */
#include <math.h>

// Configure if ePWM timer interrupt is enabled at the PIE level:
// 1 = enabled,  0 = disabled
#define PWM1_INT_ENABLE  1

// Configure the period for the timer
#define PWM1_TIMER_TBPRD   0x5FFF

// Prototype statements for functions found within this file.
interrupt void epwm1_timer_isr(void);

// Prototype statements for functions found within this file.
void spi_fifo_init(void);
void spi_init(void);
void InitEPwmTimer(void);

//Global Variables
Uint16 rdata1[500] = {0};  // received data buffer1
Uint16 rdata2[500] = {0};  // received data buffer2
Uint16 dummy;
int bufferflag = 1;	//which buffer has the most current data
int readytxflag = 0;	//if one buffer is filled
int i = 0;	//output counter
int n = 0;	//input counter

void main(void)
{

// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the F2806x_SysCtrl.c file.
   InitSysCtrl();

// This example function is found in the F2806x_Gpio.c file and
// illustrates how to set the GPIO to it's default state.
// InitGpio();  // Skipped for this example
// Setup only the GP I/O only for SPI-A functionality
// This function is found in F2806x_Spi.c
   InitSpiaGpio();
   InitSpibGpio();

// Disable CPU interrupts 
   DINT;

// Initialize PIE control registers to their default state.
// The default state is all PIE interrupts disabled and flags
// are cleared.  
// This function is found in the F2806x_PieCtrl.c file.
   InitPieCtrl();

// Disable CPU interrupts and clear all CPU interrupt flags:
   IER = 0x0000;
   IFR = 0x0000;
   
// Initialize the PIE vector table with pointers to the shell Interrupt 
// Service Routines (ISR).  
// This will populate the entire table, even if the interrupt
// is not used in this example.  This is useful for debug purposes.
// The shell ISR routines are found in F2806x_DefaultIsr.c.
// This function is found in F2806x_PieVect.c.
   InitPieVectTable();

// Interrupt that is used in this example is re-mapped to
// ISR function found within this file.
	EALLOW;  // This is needed to write to EALLOW protected registers
	PieVectTable.EPWM1_INT = &epwm1_timer_isr;
	EDIS;    // This is needed to disable write to EALLOW protected registers

// This function is found in F2806x_InitPeripherals.c
// InitPeripherals();  // Not required for this example
	InitEPwmTimer();    // For this example, only initialize the ePWM Timer
	spi_fifo_init();	  // Initialize the Spi FIFO
	spi_init();		  // init SPI

// Enable CPU INT3 which is connected to EPWM1-6 INT:
	IER |= M_INT3;

// Enable EPWM INTn in the PIE: Group 3 interrupt 1-6
	PieCtrlRegs.PIEIER3.bit.INTx1 = PWM1_INT_ENABLE;

// Initially disable time-critical interrupts
	SetDBGIER(0x0000);   //PIE groups time-critical designation

// Enable global Interrupts and higher priority real-time debug events:
	EINT;   // Enable Global interrupt INTM
	ERTM;   // Enable Global realtime interrupt DBGM

//**************** Send data to BBB*****************
	for(;;)
	{
	     if (readytxflag == 1)
	     {
		  for(i = 0; i < sizeof(rdata1); i++)
		  {
                     if (bufferflag == 2)
	   		temp=rdata1[i];
		     if (bufferflag == 1)
	   		temp=rdata2[i];
                     SpiaRegs.SPITXBUF=temp;
		     while(SpiaRegs.SPISTS.bit.INT_FLAG != 1) {}
		  }
		  readytxflag = 0;
	     }
	}
}

//*****************Receive data from ADC**************
interrupt void epwm1_timer_isr(void)
{

	// Clear INT flag for this timer
	EPwm1Regs.ETCLR.bit.INT = 1;

	SpibRegs.SPITXBUF = dummy; // Send dummy to start tx
	while(SpibRegs.SPISTS.bit.INT_FLAG !=1) {} // Wait until data received
	if (bufferflag == 1)
		rdata1[n] = SpibRegs.SPIRXBUF; // Master reads data
	if (bufferflag == 2)
		rdata2[n] = SpibRegs.SPIRXBUF; // Master reads data

	n++;

	//if buffer full, change buffer
	if (n == sizeof(rdata1))
	{
		if (bufferflag ==1)
			bufferflag = 2;
		else
			bufferflag = 1;
		n = 0;
		readytxflag = 1;
	}

	// Acknowledge this interrupt to receive more interrupts from group 3
	PieCtrlRegs.PIEACK.all = PIEACK_GROUP3;

}
//

// Step 7. Insert all local Interrupt Service Routines (ISRs) and functions here:	
void spi_init()
{    

    SpiaRegs.SPICCR.all =0x000F;	             // Reset on, rising edge, 16-bit char bits
    SpiaRegs.SPICTL.all =0x0002;    		     // Enable slave mode, normal phase,
    SpiaRegs.SPIBRR =0x007F;			     // enable talk, and SPI int disabled.
    SpiaRegs.SPICCR.all =0x008F;		     // Relinquish SPI from Reset
    SpiaRegs.SPIPRI.bit.FREE = 1;                    // Set so breakpoints don't disturb xmission
    SpiaRegs.SPIPRI.bit.TRIWIRE = 0;

    SpibRegs.SPICCR.all =0x000F;	             // Reset on, rising edge, 16-bit char bits
    SpibRegs.SPICTL.all =0x0006;    		     // Enable master mode, normal phase,
    SpibRegs.SPIBRR =0x007F;			     // enable talk, and SPI int disabled.
    SpibRegs.SPICCR.all =0x008F;		     // Relinquish SPI from Reset
    SpibRegs.SPIPRI.bit.FREE = 1;                    // Set so breakpoints don't disturb xmission

}

void spi_fifo_init()
{

// Initialize SPI FIFO registers

    SpiaRegs.SPIFFTX.all=0xE020;
    SpiaRegs.SPIFFCT.all=0x0;

    SpibRegs.SPIFFRX.all=0x6060;
    SpibRegs.SPIFFCT.all=0x0;

}

void InitEPwmTimer()
{

   EALLOW;
   SysCtrlRegs.PCLKCR0.bit.TBCLKSYNC = 0;      // Stop all the TB clocks
   EDIS;

   // Disable Sync
   EPwm1Regs.TBCTL.bit.SYNCOSEL = 11;  // Pass through

   // Initally disable Free/Soft Bits
   EPwm1Regs.TBCTL.bit.FREE_SOFT = 0;

   EPwm1Regs.TBPRD = PWM1_TIMER_TBPRD;			// Set up PWM1 Period
   EPwm1Regs.TBCTL.bit.CTRMODE = TB_COUNT_UP;    	// Count up mode
   EPwm1Regs.ETSEL.bit.INTSEL = ET_CTR_ZERO;     	// Select INT on Zero event
   EPwm1Regs.ETSEL.bit.INTEN = PWM1_INT_ENABLE;  	// Enable INT
   EPwm1Regs.ETPS.bit.INTPRD = ET_1ST;           	// Generate INT on 1st event
   EPwm1Regs.TBCTR = 0x0000;				// Clear timer counter
   EPwm1Regs.CMPA.half.CMPA = PWM1_TIMER_TBPRD/2;	//CompareA event at half of period
   EPwm1Regs.AQCTLA.all = 0x0024;			// Action-qualifiers, Set on CMPA, Clear on PRD

   EALLOW;
   SysCtrlRegs.PCLKCR0.bit.TBCLKSYNC = 1;               // Start all the timers synced
   EDIS;

}

//**************** Send data to BBB*****************
	Uint16 sdata[500];
	for (i = 0; i < 500; i++)
		sdata[i] = i;
	for(;;)
	{
	   readytxflag = 1;
	   if (readytxflag == 1)
	   {
		  for(i = 0; i < sizeof(sdata); i++)
		  {
                     SpiaRegs.SPITXBUF=sdata[i];
		     while(SpiaRegs.SPISTS.bit.INT_FLAG != 1) {}
		  }
	   }
	}

for(i = 0; i < sizeof(sdata); i++)
   {
      SpiaRegs.SPIDAT=sdata[i];
      while(SpiaRegs.SPIDAT != 0xFFFF){}
   }