TMS320F28027: Code Example for SCI receiving more than only 4 chars

//###########################################################################
//
// FILE:    Example_2802x0Sci_Echoback.c
//
// TITLE:   f2802x0 Device SCI Echoback.
//
// ASSUMPTIONS:
//
//    This program requires the f2802x0 header files.
//    As supplied, this project is configured for "boot to SARAM" operation.
//
//    Connect the SCI-A port to a PC via a transciever and cable.
//    The PC application 'hypterterminal' can be used to view the data
//    from the SCI and to send information to the SCI.  Characters received
//    by the SCI port are sent back to the host.
//
//    As supplied, this project is configured for "boot to SARAM"
//    operation.  The 2802x0 Boot Mode table is shown below.
//    For information on configuring the boot mode of an eZdsp,
//    please refer to the documentation included with the eZdsp,
//
//    $Boot_Table
//    While an emulator is connected to your device, the TRSTn pin = 1,
//    which sets the device into EMU_BOOT boot mode. In this mode, the
//    peripheral boot modes are as follows:
//
//      Boot Mode:   EMU_KEY        EMU_BMODE
//                   (0xD00)         (0xD01)
//      ---------------------------------------
//      Wait         !=0x55AA        X
//      I/O          0x55AA          0x0000
//      SCI          0x55AA          0x0001
//      Wait         0x55AA          0x0002
//      Get_Mode     0x55AA          0x0003
//      SPI          0x55AA          0x0004
//      I2C          0x55AA          0x0005
//      OTP          0x55AA          0x0006
//      Wait         0x55AA          0x0007
//      Wait         0x55AA          0x0008
//      SARAM        0x55AA          0x000A   <-- "Boot to SARAM"
//      Flash        0x55AA          0x000B
//      Wait         0x55AA          Other
//
//   Write EMU_KEY to 0xD00 and EMU_BMODE to 0xD01 via the debugger
//   according to the Boot Mode Table above. Build/Load project,
//   Reset the device, and Run example
//
//   $End_Boot_Table
//
//
//
// DESCRIPTION:
//
//
//    This test receives and echo-backs data through the SCI-A port.
//
//    1) Configure hyperterminal:
//       Use the included hyperterminal configuration file SCI_96.ht.
//       To load this configuration in hyperterminal: file->open
//       and then select the SCI_96.ht file.
//    2) Check the COM port.
//       The configuration file is currently setup for COM1.
//       If this is not correct, disconnect Call->Disconnect
//       Open the File-Properties dialog and select the correct COM port.
//    3) Connect hyperterminal Call->Call
//       and then start the 2802x0 SCI echoback program execution.
//    4) The program will print out a greeting and then ask you to
//       enter a character which it will echo back to hyperterminal.
//
//
//    Watch Variables:
//       LoopCount for the number of characters sent
//       ErrorCount
//
//
//###########################################################################
// $TI Release: F2802x0 Support Library v230 $
// $Release Date: Fri May  8 07:47:46 CDT 2015 $
// $Copyright: Copyright (C) 2008-2015 Texas Instruments Incorporated -
//             http://www.ti.com/ ALL RIGHTS RESERVED $
//###########################################################################

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

// Prototype statements for functions found within this file.
void scia_echoback_init(void);
void scia_fifo_init(void);
void scia_xmit(int a);
void scia_msg(char *msg);

// Global counts used in this example
uint16_t LoopCount;
uint16_t ErrorCount;

void main(void)
{
    Uint16 ReceivedChar;
    Uint16 y = 0;
    char *msg;

// WARNING: Always ensure you call memcpy before running any functions from RAM
// InitSysCtrl includes a call to a RAM based function and without a call to
// memcpy first, the processor will go "into the weeds"
   #ifdef _FLASH
	memcpy(&RamfuncsRunStart, &RamfuncsLoadStart, (size_t)&RamfuncsLoadSize);
   #endif

// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the f2802x0_SysCtrl.c file.
   InitSysCtrl();

// Step 2. Initialize GPIO:
// This example function is found in the f2802x0_Gpio.c file and
// illustrates how to set the GPIO to it's default state.
   // InitGpio(); Skipped for this example

// For this example, only init the pins for the SCI-A port.
// This function is found in the f2802x0_Sci.c file.
   InitSciaGpio();

// 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 f2802x0_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 f2802x0_DefaultIsr.c.
// This function is found in f2802x0_PieVect.c.
   InitPieVectTable();

// Step 4. Initialize all the Device Peripherals:
// Not required for this example

// Step 5. User specific code:

    LoopCount = 0;
    ErrorCount = 0;

    scia_fifo_init();      // Initialize the SCI FIFO
    scia_echoback_init();  // Initialize SCI for echoback

    msg = "\r\n\n\nHello World!\0";
    scia_msg(msg);

    msg = "\r\nYou will enter a character, and the DSP will echo it back! \n\0";
    scia_msg(msg);

    for(;;)
    {
       /*
       msg = "\r\nEnter a character: \0";
       scia_msg(msg);

       // Wait for inc character
       while(SciaRegs.SCIFFRX.bit.RXFFST !=1) { } // wait for XRDY =1 for empty state

       // Get character
       ReceivedChar = SciaRegs.SCIRXBUF.all;

       // Echo character back
       msg = "  You sent: \0";
       scia_msg(msg);
       scia_xmit(ReceivedChar);

       */

    	if(SciaRegs.SCIFFRX.bit.RXFFST > 0)
   		{
    		if(SciaRegs.SCIRXBUF.all != '\0')
   		    {
   		        msg[y] = SciaRegs.SCIRXBUF.all;
   		        y++;
   		    }
    		else
    		{
    			msg[y] = '\0';
    			y = 0;
    		}
    		scia_msg(msg);
   		}

       LoopCount++;
    }
}

// Test 1,SCIA  DLB, 8-bit word, baud rate 0x000F, default, 1 STOP bit, no parity
void scia_echoback_init()
{
    // Note: Clocks were turned on to the SCIA peripheral
    // in the InitSysCtrl() function

    SciaRegs.SCICCR.all =0x0007;   // 1 stop bit,  No loopback
                                   // No parity,8 char bits,
                                   // async mode, idle-line protocol
    SciaRegs.SCICTL1.all =0x0003;  // enable TX, RX, internal SCICLK,
                                   // Disable RX ERR, SLEEP, TXWAKE
    SciaRegs.SCICTL2.all =0x0003;
    SciaRegs.SCICTL2.bit.TXINTENA =1;
    SciaRegs.SCICTL2.bit.RXBKINTENA =1;

    // SCI BRR = LSPCLK/(SCI BAUDx8) - 1
    #if (CPU_FRQ_60MHZ)
        SciaRegs.SCIHBAUD    =0x0000;  // 9600 baud @LSPCLK = 15MHz (60 MHz SYSCLK).
        SciaRegs.SCILBAUD    =0x00C2;
    #elif (CPU_FRQ_50MHZ)
        SciaRegs.SCIHBAUD     =0x0000;  // 9600 baud @LSPCLK = 12.5 MHz (50 MHz SYSCLK)
        SciaRegs.SCILBAUD    =0x00A1;
    #elif (CPU_FRQ_40MHZ)
        SciaRegs.SCIHBAUD    =0x0000;  // 9600 baud @LSPCLK = 10MHz (40 MHz SYSCLK).
        SciaRegs.SCILBAUD    =0x0081;
    #endif

    SciaRegs.SCICTL1.all =0x0023;  // Relinquish SCI from Reset
}

// Transmit a character from the SCI
void scia_xmit(int a)
{
    while (SciaRegs.SCIFFTX.bit.TXFFST != 0) {}
    SciaRegs.SCITXBUF=a;
}

void scia_msg(char * msg)
{
    int i;
    i = 0;
    while(msg[i] != '\0')
    {
        scia_xmit(msg[i]);
        i++;
    }
}

// Initialize the SCI FIFO
void scia_fifo_init()
{
    SciaRegs.SCIFFTX.all=0xE040;
    SciaRegs.SCIFFRX.all=0x2044;
    SciaRegs.SCIFFCT.all=0x0;
}

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