//###########################################################################
//
// FILE:	Example_2833xSci_FFDLB.c
//
// TITLE:	SCI Digital Loop Back Example
//
//! \addtogroup f2833x_example_list
//! <h1>SCI Digital Loop Back (scia_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.
//!
//!  This test uses the loopback test mode of the SCI module to send
//!  characters starting with 0x00 through 0xFF.  The test will send
//!  a character and then check the receive buffer for a correct match.
//!
//!  \b Watch \b Variables \n
//!  - LoopCount  - Number of characters sent
//!  - ErrorCount - Number of errors detected
//!  - SendChar - Character sent
//!  - ReceivedChar - Character received
//
//###########################################################################
// $TI Release: $
// $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
//
void scia_loopback_init(void);
void scia_fifo_init(void);
void scia_xmit(int a);
void error();
__interrupt void scia_rx_isr(void);
__interrupt void scia_tx_isr(void);

//
// Globals
//
Uint16 LoopCount;
Uint16 ErrorCount;

//
// Main
//
void main(void)
{
    Uint16 SendChar;
    Uint16 ReceivedChar;

    //
    // Step 1. Initialize System Control registers, PLL, WatchDog, 
    // Clocks to default state:
    // This function is found in the DSP2833x_SysCtrl.c file.
    //
    InitSysCtrl();

    //
    // Step 2. Select GPIO for the device or for the specific application:
    // This function is found in the DSP2833x_Gpio.c file.
    //
    
    //
    // skip this as this is example selects the I/O for SCI-A in this 
    // file itself
    //
    // InitGpio(); 
    InitSciGpio();

    //
    // Step 3. Initialize PIE vector table:
    // The PIE vector table is initialized with pointers to shell Interrupt
    // Service Routines (ISR).  The shell routines are found in 
    // DSP2833x_DefaultIsr.c. Insert user specific ISR code in the 
    // appropriate shell ISR routine in the DSP28_DefaultIsr.c file.
    //

    //
    // Disable and clear all CPU interrupts
    //
    DINT;
    IER = 0x0000;
    IFR = 0x0000;

    //
    // Initialize Pie Control Registers To Default State:
    // This function is found in the DSP2833x_PieCtrl.c file.
    //
    // InitPieCtrl();  PIE is not used for this example

    //
    // Initialize the PIE Vector Table To a Known State:
    // This function is found in DSP2833x_PieVect.c.
    // This function populates the PIE vector table with pointers
    // to the shell ISR functions found in DSP2833x_DefaultIsr.c.
    //
    InitPieVectTable();

    //
    // Enable CPU and PIE interrupts
    // This example function is found in the DSP2833x_PieCtrl.c file.
    //
    EnableInterrupts();

    //
    // Step 4. Initialize all the Device Peripherals to a known state:
    // This function is found in DSP2833x_InitPeripherals.c
    //
    // InitPeripherals(); skip this for SCI tests

    //
    // Step 5. User specific functions, Reassign vectors (optional), 
    // Enable Interrupts:
    //
    LoopCount = 0;
    ErrorCount = 0;

    scia_fifo_init();	   // Initialize the SCI FIFO
    scia_loopback_init();  // Initialize SCI for digital loop back

    //
    // Note: Autobaud lock is not required for this example
    //

    //
    // Send a character starting with 0
    //
    SendChar = 0;

    //
    // Step 6. Send Characters forever starting with 0x00 and going through
    // 0xFF.  After sending each, check the receive buffer for the correct 
    // value
    //
    for(;;)
    {
        scia_xmit(SendChar);
        
        //
        // wait for RRDY/RXFFST =1 for 1 data available in FIFO
        //
        while(SciaRegs.SCIFFRX.bit.RXFFST !=1) 
        {
            
        }

        //
        // Check received character
        //
        ReceivedChar = SciaRegs.SCIRXBUF.all;
        if(ReceivedChar != SendChar)
        {
            error();
        }

        //
        // Move to the next character and repeat the test
        //
        SendChar++;
        
        //
        // Limit the character to 8-bits
        //
        SendChar &= 0x00FF;
        LoopCount++;
    }
}

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

//
// error - 
//
void 
error()
{
    ErrorCount++;
    //__asm("     ESTOP0");  // Uncomment to stop the test here
    //for (;;);
}

//
// scia_loopback_init - Test 1, SCIA  DLB, 8-bit word, baud rate 0x000F, 
// default, 1 STOP bit, no parity
//
void 
scia_loopback_init()
{
    //
    // Note: Clocks were turned on to the SCIA peripheral
    // in the InitSysCtrl() function
    //
    
    //
    // 1 stop bit,  No loopback, No parity,8 char bits, async mode, 
    // idle-line protocol
    //
    SciaRegs.SCICCR.all =0x0007;
    
    //
    // enable TX, RX, internal SCICLK, Disable RX ERR, SLEEP, TXWAKE
    //
    SciaRegs.SCICTL1.all =0x0003;
    SciaRegs.SCICTL2.all =0x0003;
    SciaRegs.SCICTL2.bit.TXINTENA =0;
    SciaRegs.SCICTL2.bit.RXBKINTENA =0;
    SciaRegs.SCIHBAUD    =0x0000;
    SciaRegs.SCILBAUD    =0x000F;
    SciaRegs.SCICCR.bit.LOOPBKENA =1;   // Enable loop back
    SciaRegs.SCICTL1.all =0x0023;       // Relinquish SCI from Reset
}

//
// scia_xmit - Transmit a character from the SCI
//
void 
scia_xmit(int a)
{
    SciaRegs.SCITXBUF=a;
}

//
// scia_fifo_init - Initialize the SCI FIFO
//
void 
scia_fifo_init()
{
    SciaRegs.SCIFFTX.all=0xE040;
    SciaRegs.SCIFFRX.all=0x204f;
    SciaRegs.SCIFFCT.all=0x0;
}

//
// End of File
//

