TMS320F28069: SPI

//###########################################################################
//
// FILE:   Example_2806xSpi_FFDLB.c
//
// TITLE:  SPI Digital Loop Back Example
//
//!  \addtogroup f2806x_example_list
//!  <h1>SPI Digital Loop Back(spi_loopback)</h1>
//!
//!  This program uses the internal loop back test mode of the peripheral. 
//!  Other then boot mode pin configuration, no other hardware configuration
//!  is required. Interrupts are not used.
//!
//!  A stream of data is sent and then compared to the received stream.
//!  The sent data looks like this: \n
//!  0000 0001 0002 0003 0004 0005 0006 0007 .... FFFE FFFF \n
//!  This pattern is repeated forever.
//!  
//!  \b Watch \b Variables \n     
//!  - \b sdata , sent data
//!  - \b rdata , received data
//		
////###########################################################################		
// $TI Release: F2806x Support Library v2.04.00.00 $
// $Release Date: Mon May 27 06:46:38 CDT 2019 $
// $Copyright:
// Copyright (C) 2009-2019 Texas Instruments Incorporated - http://www.ti.com/
//
// Redistribution and use in source and binary forms, with or without 
// modification, are permitted provided that the following conditions 
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// 
//   Redistributions of source code must retain the above copyright 
//   notice, this list of conditions and the following disclaimer.
// 
//   Redistributions in binary form must reproduce the above copyright
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//   distribution.
// 
//   Neither the name of Texas Instruments Incorporated nor the names of
//   its contributors may be used to endorse or promote products derived
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// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// $
//#############################################################################

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

//
// Function Prototypes
//
void spi_xmit(Uint16 a);
void spi_fifo_init(void);
void spi_init(void);
void error(void);

//
// Main
//
void main(void)
{
    Uint16 sdata;  // send data
    Uint16 rdata;  // received data

    //
    // 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 = 0x0000;							
    for(;;)
    {
        //        
        // Transmit data
        //
        spi_xmit(sdata);
        
        //
        // Wait until data is received
        //
        while(SpiaRegs.SPIFFRX.bit.RXFFST !=1)
        {
            
        }

        //        
        // Check against sent data
        //
        rdata = SpiaRegs.SPIRXBUF;
        if(rdata != sdata)
        {
            error();
        }
        
        sdata++;
    }
} 	

//
// error - Step 7. Insert all local Interrupt Service Routines (ISRs) 
// and functions here
//
void
error(void)
{
    __asm("     ESTOP0");						// Test failed!! Stop!
    for (;;);
}

//
// spi_init - 
//
void
spi_init()
{    
    SpiaRegs.SPICCR.all =0x000F;  // Reset on, rising edge, 16-bit char bits
    
    //
    // Enable master mode, normal phase, enable talk, and SPI int disabled.
    //
    SpiaRegs.SPICTL.all =0x0006;
    
    SpiaRegs.SPIBRR =0x007F;									
    SpiaRegs.SPICCR.all =0x009F;   // Relinquish SPI from Reset
    SpiaRegs.SPIPRI.bit.FREE = 1;  // Set so breakpoints don't disturb xmission
}

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

//
// spi_fifo_init - 
//
void
spi_fifo_init(void)										
{
    //
    // Initialize SPI FIFO registers
    //
    SpiaRegs.SPIFFTX.all=0xE040;
    SpiaRegs.SPIFFRX.all=0x2044;
    SpiaRegs.SPIFFCT.all=0x0;
}  

//
// End of File
//

The above code is from ti example code for SPI, though data is received correctly in rdata but I probe the pin (GPIO18), there is no clock pulse. I also tried to turn off loopback but there is no clock pulse on the pin.

Any help is highly appreciated. Thanks.