TMS320F28377S: TMS320F28377S

Tool/software:

Hello,

I have been trying to communicate over SCI on a custom board with TMS320F28377S. The board has an external clock source of 25MHz connected to pin X1 of the MCU. At the moment, when I use the provided SCI echo loopback example, all I get on the terminal is random data being spit out. Below is my modified example. 

//###########################################################################
//
// FILE:    Example_2837xSSci_Echoback.c
//
// TITLE:   SCI Echoback.
//
//! \addtogroup cpu01_example_list
//! <h1>SCI Echoback (sci_echoback)</h1>
//!
//!  This test receives and echo-backs data through the SCI-A port.
//!
//!  The PC application 'hyperterminal' or another terminal
//!  such as 'putty' 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.
//!
//!  \b Running \b the \b Application
//!  -# Configure hyperterminal or another terminal such as putty:
//!
//!  For hyperterminal you can use the included hyperterminal configuration
//!  file SCI_96.ht.
//!  To load this configuration in hyperterminal
//!    -# Open hyperterminal
//!    -# Go to file->open
//!    -# Browse to the location of the project and
//!       select the SCI_96.ht file.
//!  -# Check the COM port.
//!  The configuration file is currently setup for COM1.
//!  If this is not correct, disconnect (Call->Disconnect)
//!  Open the File-Properties dialogue and select the correct COM port.
//!  -# Connect hyperterminal Call->Call
//!  and then start the 2837xS SCI echoback program execution.
//!  -# The program will print out a greeting and then ask you to
//!  enter a character which it will echo back to hyperterminal.
//!
//!  \note If you are unable to open the .ht file, or you are using
//!  a different terminal, you can open a COM port with the following settings
//!  -  Find correct COM port
//!  -  Bits per second = 9600
//!  -  Date Bits = 8
//!  -  Parity = None
//!  -  Stop Bits = 1
//!  -  Hardware Control = None
//!
//!  \b Watch \b Variables \n
//!  - LoopCount - the number of characters sent
//!
//! \b External \b Connections \n
//!  Connect the SCI-A port to a PC via a transceiver and cable.
//!  - GPIO28 is SCI_A-RXD (Connect to Pin3, PC-TX, of serial DB9 cable)
//!  - GPIO29 is SCI_A-TXD (Connect to Pin2, PC-RX, of serial DB9 cable)
//!
//
//###########################################################################
// $TI Release: F2837xS Support Library v3.04.00.00 $
// $Release Date: Sun Mar 25 13:27:27 CDT 2018 $
// $Copyright:
// Copyright (C) 2014-2018 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 
// are met:
// 
//   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
//   notice, this list of conditions and the following disclaimer in the 
//   documentation and/or other materials provided with the   
//   distribution.
// 
//   Neither the name of Texas Instruments Incorporated nor the names of
//   its contributors may be used to endorse or promote products derived
//   from this software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// $
//###########################################################################

//
// Included Files
//
#include "F28x_Project.h"

//
// Globals
//
Uint16 LoopCount;
Uint16 rDataA[72] = {0};    // Received data for SCI-A
Uint16 rDataSizeA = 0;

//
// Function Prototypes
//
void scia_echoback_init(void);
void scia_fifo_init(void);
void scia_xmit(int a);
void scia_msg(char *msg);
interrupt void sciaRxFifoIsr(void);
//
// Main
//
void main(void)
{
    char *msg;

    //
    // Step 1. Initialize System Control:
    // PLL, WatchDog, enable Peripheral Clocks
    // This example function is found in the F2837xS_SysCtrl.c file.
    //
       InitSysCtrl();

    //
    // Step 2. Initialize GPIO:
    // This example function is found in the F2837xS_Gpio.c file and
    // illustrates how to set the GPIO to it's default state.
    //
       InitGpio();

    //
    // For this example, only init the pins for the SCI-A port.
    //  GPIO_SetupPinMux() - Sets the GPxMUX1/2 and GPyMUX1/2 register bits
    //  GPIO_SetupPinOptions() - Sets the direction and configuration of the GPIOS
    // These functions are found in the F2837xS_Gpio.c file.
    //
       GPIO_SetupPinMux(28, GPIO_MUX_CPU1, 1);
       GPIO_SetupPinOptions(28, GPIO_INPUT, GPIO_PUSHPULL);
       GPIO_SetupPinMux(29, GPIO_MUX_CPU1, 1);
       GPIO_SetupPinOptions(29, GPIO_OUTPUT, GPIO_ASYNC);

    //
    // 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 F2837xS_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 F2837xS_DefaultIsr.c.
    // This function is found in F2837xS_PieVect.c.
    //
       InitPieVectTable();

       EALLOW;  // This is needed to write to EALLOW protected registers
       PieVectTable.SCIA_RX_INT = &sciaRxFifoIsr;
//       PieVectTable.SCIA_TX_INT = &sciaTxFifoIsr;
       EDIS;    // This is needed to disable write to EALLOW protected registers


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


       PieCtrlRegs.PIECTRL.bit.ENPIE = 1;   // Enable the PIE block
       PieCtrlRegs.PIEIER9.bit.INTx1 = 1;   // PIE Group 9, INT1
       PieCtrlRegs.PIEIER9.bit.INTx2 = 1;   // PIE Group 9, INT2
       IER = 0x100;                         // Enable CPU INT
       EINT;

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

   for(;;)
   {
       msg = "Hello\r";
       scia_msg(msg);

       //
       // Wait for inc character
       //
/*       while(SciaRegs.SCIFFRX.bit.RXFFST != 4) {}

           rdataA[0] = SciaRegs.SCIRXBUF.bit.SAR;
           rdataA[1] = SciaRegs.SCIRXBUF.bit.SAR;
           rdataA[2] = SciaRegs.SCIRXBUF.bit.SAR;
           rdataA[3] = SciaRegs.SCIRXBUF.bit.SAR;*/

       //
       // Get character
       //

       DELAY_US(500000);

       rDataSizeA = 0;

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

//
//  scia_echoback_init - 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.SCICTL1.bit.RXERRINTENA = 1;

    SciaRegs.SCICTL2.all = 0x0003;
    SciaRegs.SCICTL2.bit.TXINTENA = 1;
    SciaRegs.SCICTL2.bit.RXBKINTENA = 1;

    //
    // SCIA at 9600 baud
    // @LSPCLK = 50 MHz (200 MHz SYSCLK) HBAUD = 0x02 and LBAUD = 0x8B.
    // @LSPCLK = 30 MHz (120 MHz SYSCLK) HBAUD = 0x01 and LBAUD = 0x86.
    //
    SciaRegs.SCIHBAUD.all = 0x0000;
    SciaRegs.SCILBAUD.all = 0x0081;

//    SciaRegs.SCIPRI.bit.FREESOFT = 2;

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

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

//
// scia_msg - Transmit message via SCIA
//
void scia_msg(char * msg)
{
    int i;
    i = 0;
    while(msg[i] != '\0')
    {
        scia_xmit(msg[i]);
        i++;
    }
}

interrupt void sciaRxFifoIsr(void)
{
    uint16_t i;

    for (i = 0; i < SciaRegs.SCIFFRX.bit.RXFFST; i++)
    {
        rDataA[rDataSizeA] = SciaRegs.SCIRXBUF.bit.SAR;
        rDataSizeA++;
/*        if(2 == flagRwFSS)
        {
            if(0x60 != rDataA[0])
                rDataSizeA--;
            if(0x08 == rDataSizeA)
                rDataFlagRwFss = 2;
        }
        else if (1 == flagRwFSS)
        {
            if(0x0A == rDataA[rDataSizeA-1])
            {
                rDataFlagRwFss = 1;
            }
        }*/
    }

    SciaRegs.SCIFFRX.bit.RXFFOVRCLR=1;   // Clear Overflow flag
    SciaRegs.SCIFFRX.bit.RXFFINTCLR=1;   // Clear Interrupt flag

    PieCtrlRegs.PIEACK.all|=PIEACK_GROUP9;       // Issue PIE ack
}

//
// scia_fifo_init - Initialize the SCI FIFO
//
void scia_fifo_init()
{
    SciaRegs.SCIFFTX.all = 0xE040;
    SciaRegs.SCIFFRX.all = 0x2061;
    SciaRegs.SCIFFCT.all = 0x0;
}

//
// End of file
//

I've configured Pin 28 and 29 for SCI communication. I have tried different LSPCLK settings at 10MHz, 20MHz, 25MHz, 30MHz etc. Could you provide a fix for the issue? 

Best regards.