//###########################################################################
//
// FILE:	Example_2833xSpi_FFDLB.c
//
// TITLE:	SPI Digital Loop Back Example
//
//!  \addtogroup f2833x_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
//!  - sdata - Sent data
//!  - rdata - Received data
//
//###########################################################################
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// $Release Date: $
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//
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// 
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// 
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// $
//###########################################################################

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

//
// Function Prototypes
//
//__interrupt void ISRTimer2(void);
void delay_loop(void);
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 DSP2833x_SysCtrl.c file.
    //
    InitSysCtrl();

    //
    // Step 2. Initialize GPIO:
    // This example function is found in the DSP2833x_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 DSP2833x_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 DSP2833x_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 DSP2833x_DefaultIsr.c.
    // This function is found in DSP2833x_PieVect.c.
    //
    InitPieVectTable();

    //
    // Step 4. Initialize all the Device Peripherals:
    // This function is found in DSP2833x_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++;
    }
}

//
// delay_loop - Step 7. Insert all local Interrupt Service Routines (ISRs) and 
// functions here:
//
void 
delay_loop()
{
    long      i;
    for (i = 0; i < 1000000; i++)
    {
        
    }
}

//
// error -
//
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()
{
    //
    // Initialize SPI FIFO registers
    //
    SpiaRegs.SPIFFTX.all=0xE040;
    SpiaRegs.SPIFFRX.all=0x204f;
    SpiaRegs.SPIFFCT.all=0x0;
}

//
// End of File
//