CCS/TMS320F28069M: SPIA RXBUF gets 65535

Tool/software: Code Composer Studio

I have written below code for getting data from encoder using SPIA

I started initially by sending dummy data(0x73) from F28069 to RLS encoder but RXBUF and RXEMU reads 65535 all the time.

SPI Mode is 0.

I doubt my SPIBRR calculation , still I calculated as 90M/8*15200 = 0x61

Below is my code. Please suggest where I am going wrong to get correct data from encoders

In oscilloscope , I can see MOSI,SCK and CS signal as required but MISO is always high

#include "DSP28x_Project.h" // Device Headerfile and Examples Include File

// Prototype statements for functions found within this file.
Uint16 spi_xmit(Uint16 a);
void spi_fifo_init(void);
void spi_init(void);
void error(void);

void delay_loop( );
int n=0;
int m=0;
//int i=0;


Uint16 sdata; // send data
Uint16 sdata1;
Uint16 rdata=0; // received data
Uint16 rdata1=0;
Uint16 rdata2=0;
Uint16 rdata3=0;
int flag=1;
//void putsUart0(Uint16 str)
//{
//Uint16 i;
//for (i = 0; i < strlen(str); i++)
// putcUart0(str[i]);
//}

void main(void)
{

// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the F2806x_SysCtrl.c file.
InitSysCtrl();

// Step 2. Initalize GPIO:
// 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();

// Step 3. Clear all interrupts and initialize PIE vector table:
// 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();

// Step 4. Initialize all the Device Peripherals:
// This function is found in F2806x_InitPeripherals.c
// InitPeripherals(); // Not required for this example
spi_fifo_init(); // Initialize the Spi FIFO
spi_init(); // init SPI

// Step 5. User specific code:
// Interrupts are not used in this example. 
sdata = 0x73;
sdata1=0x00;

for(;;)
{
// GpioCtrlRegs.GPAPUD.bit.GPIO19 = 1;
// Transmit data


spi_xmit(sdata);
delay_loop();
// Wait until data is received
while(SpiaRegs.SPIFFRX.bit.RXFFST !=1) { }
//rdata1 =spi_xmit(sdata);

// Wait until data is received
// while(SpiaRegs.SPIFFRX.bit.RXFFST !=1) { }
//
// Check against sent data
rdata = SpiaRegs.SPIRXBUF ;
// delay_loop();



}
}

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

void error(void)
{
__asm(" ESTOP0"); // Test failed!! Stop!
for (;;);
}
void delay_loop( )
{
int i;
for (i = 0; i < 1000; i++){}

}

void spi_init()
{ 
SpiaRegs.SPICCR.all =0x000F; // Reset on, rising edge, 16-bit char bits //llop back mode is enabled
SpiaRegs.SPICTL.all =0x0006; // Enable master mode, normal phase,
// enable talk, and SPI int disabled.
SpiaRegs.SPIBRR = 0x61;
SpiaRegs.SPICCR.all =0x008F; // Relinquish SPI from Reset
SpiaRegs.SPIPRI.bit.FREE = 1; // Set so breakpoints don't disturb xmission
}

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

void spi_fifo_init() 
{
// Initialize SPI FIFO registers
//SpiaRegs.SPIFFTX.all=0xE040;
SpiaRegs.SPIFFTX.all=0xE040;
SpiaRegs.SPIFFRX.all=0x2044;
// SpiaRegs.SPIFFRX.all=0x6060F;
SpiaRegs.SPIFFCT.all=0x00;
}

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// No more.
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