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SCI-B FIFO interrupt not working

Rachit Jain
Intellectual 265 points
Other Parts Discussed in Thread: TMS320F2812

Hello,

I am using SCI-B interface on my TMS320F2812. I am using FIFO enhancements and just receiving one character for the time being. So i have written the the program to generate an interrupt when a single character is received.

But the the problem is that the interrupt is not running for some reason and i cannot find out why. Can someone please help me.

Here is my code-

#include "DSP281x_Device.h"   
#include "DSP281x_Examples.h"
#include <stdio.h>


interrupt void scibRxFifoIsr(void);
void InitSystem(void);
void Gpio_select(void);
void InitPieCtrl(void);
interrupt void scibRxFifoIsr(void);  
void scib_fifo_init(void);
void Delay_1ms(long);  
 

unsigned char rdataB;    // Received data for SCI-B

void main(void)   
    {    
        
       
    // Initialize System Control:  
       InitSystem();   
       
    // Initalize GPIO:    
       Gpio_select();     
       
    //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.     
       InitPieCtrl();

   // Disable CPU interrupts and clear all CPU interrupt flags:   
       IER = 0x0000;   
       IFR = 0x0000;  

   // Interrupts that are used in this example are re-mapped to   
    // ISR functions found within this file.     
       EALLOW;  
       PieVectTable.RXBINT = &scibRxFifoIsr;      
       EDIS;  

    //Initialize all the Device Peripherals:
      scib_fifo_init();  // Init SCI-B
      
       
    // Enable interrupts required for this example   
     PieCtrlRegs.PIEIER9.bit.INTx3=1;  // PIE Group 9, INT3
     IER = 0x100; // Enable CPU INT
     EINT;            

    // IDLE loop. Just sit and loop forever (optional):    
        for(;;);   
       
    }    

void InitSystem(void)
{
       EALLOW;
       SysCtrlRegs.WDCR= 0x0068;        // Setup the watchdog
                                       // 0x00E8  to disable the Watchdog , Prescaler = 1
                                       // 0x00AF  to NOT disable the Watchdog, Prescaler = 64
       SysCtrlRegs.SCSR = 0;             // Watchdog generates a RESET    
       SysCtrlRegs.PLLCR.bit.DIV = 10;    // Setup the Clock PLL to multiply by 5
    
       SysCtrlRegs.HISPCP.all = 0x1; // Setup Highspeed Clock Prescaler to divide by 2
       SysCtrlRegs.LOSPCP.all = 0x2; // Setup Lowspeed CLock Prescaler to divide by 4
          
       // Peripheral clock enables set for the selected peripherals.   
       SysCtrlRegs.PCLKCR.bit.EVAENCLK=0;
       SysCtrlRegs.PCLKCR.bit.EVBENCLK=0;
       SysCtrlRegs.PCLKCR.bit.SCIAENCLK=0;
       SysCtrlRegs.PCLKCR.bit.SCIBENCLK=1;
       SysCtrlRegs.PCLKCR.bit.MCBSPENCLK=0;
       SysCtrlRegs.PCLKCR.bit.SPIENCLK=0;
       SysCtrlRegs.PCLKCR.bit.ECANENCLK=0;
       SysCtrlRegs.PCLKCR.bit.ADCENCLK=0;
       EDIS;
}

void Gpio_select(void)
{
    EALLOW;
    GpioMuxRegs.GPAMUX.all = 0x0;    // all GPIO port Pin's to I/O
    GpioMuxRegs.GPBMUX.all = 0x0;   
    GpioMuxRegs.GPDMUX.all = 0x0;
    GpioMuxRegs.GPFMUX.all = 0x0;        
    GpioMuxRegs.GPEMUX.all = 0x0;
    GpioMuxRegs.GPGMUX.all = 0x0;
    GpioMuxRegs.GPGMUX.bit.SCIRXDB_GPIOG5 = 1; //SCI-RX
    GpioMuxRegs.GPGMUX.bit.SCITXDB_GPIOG4 = 1; //SCI-TX            
                                        
    GpioMuxRegs.GPADIR.all = 0x0;    // GPIO PORT  as input
    GpioMuxRegs.GPBDIR.all = 0x00FF;    // GPIO Port B15-B8 input , B7-B0 output
    GpioMuxRegs.GPDDIR.all = 0x0;    // GPIO PORT  as input
    GpioMuxRegs.GPEDIR.all = 0x0;    // GPIO PORT  as input
    GpioMuxRegs.GPFDIR.all = 0x0;    // GPIO PORT  as input
    GpioMuxRegs.GPGDIR.all = 0x0;    // GPIO PORT  as input

    GpioMuxRegs.GPAQUAL.all = 0x0;    // Set GPIO input qualifier values to zero
    GpioMuxRegs.GPBQUAL.all = 0x0;
    GpioMuxRegs.GPDQUAL.all = 0x0;
    GpioMuxRegs.GPEQUAL.all = 0x0;
    EDIS;
}  
void InitPieCtrl(void)   
{   
    // Disable Interrupts at the CPU level:   
    DINT;   
   
    // Disable the PIE   
    PieCtrlRegs.PIECRTL.bit.ENPIE = 0;   
   
    // Clear all PIEIER registers:   
    PieCtrlRegs.PIEIER1.all = 0;   
    PieCtrlRegs.PIEIER2.all = 0;   
    PieCtrlRegs.PIEIER3.all = 0;       
    PieCtrlRegs.PIEIER4.all = 0;   
    PieCtrlRegs.PIEIER5.all = 0;   
    PieCtrlRegs.PIEIER6.all = 0;   
    PieCtrlRegs.PIEIER7.all = 0;   
    PieCtrlRegs.PIEIER8.all = 0;   
    PieCtrlRegs.PIEIER9.all = 0;   
    PieCtrlRegs.PIEIER10.all = 0;   
    PieCtrlRegs.PIEIER11.all = 0;   
    PieCtrlRegs.PIEIER12.all = 0;   
   
    // Clear all PIEIFR registers:   
    PieCtrlRegs.PIEIFR1.all = 0;   
    PieCtrlRegs.PIEIFR2.all = 0;   
    PieCtrlRegs.PIEIFR3.all = 0;       
    PieCtrlRegs.PIEIFR4.all = 0;   
    PieCtrlRegs.PIEIFR5.all = 0;   
    PieCtrlRegs.PIEIFR6.all = 0;   
    PieCtrlRegs.PIEIFR7.all = 0;   
    PieCtrlRegs.PIEIFR8.all = 0;   
    PieCtrlRegs.PIEIFR9.all = 0;   
    PieCtrlRegs.PIEIFR10.all = 0;   
    PieCtrlRegs.PIEIFR11.all = 0;   
    PieCtrlRegs.PIEIFR12.all = 0;   
   
   
}   

 void scib_fifo_init()                                          
    {   
       ScibRegs.SCICCR.all =0x0007;    // 1 stop bit,  No loopback    
                                       // No parity,8 char bits,   
                                       // async mode, idle-line protocol   
       ScibRegs.SCICTL1.all =0x0003;   // enable TX, RX, internal SCICLK,    
                                       // Disable RX ERR, SLEEP, TXWAKE      
       ScibRegs.SCICTL2.bit.RXBKINTENA =1;   
       ScibRegs.SCIHBAUD    =0x01;   
       ScibRegs.SCILBAUD    =0xE7;   
       ScibRegs.SCICCR.bit.LOOPBKENA =1; // Enable loop back       
       ScibRegs.SCIFFRX.all=0x0021;   
       ScibRegs.SCIFFCT.all=0x00;   
       
       ScibRegs.SCICTL1.all =0x0023;     // Relinquish SCI from Reset    
       ScibRegs.SCIFFRX.bit.RXFIFORESET=1;      
             
    }   

interrupt void scibRxFifoIsr(void)   
    {   
         
        rdataB=ScibRegs.SCIRXBUF.all;  // Read data   
    
        if(rdataB=='a')
            {
        
                 GpioDataRegs.GPBDAT.all = 0x00;
                Delay_1ms(1000);
                                  
            }
                                      
        ScibRegs.SCIFFRX.bit.RXFFOVRCLR=1;  // Clear Overflow flag   
        ScibRegs.SCIFFRX.bit.RXFFINTCLR=1;  // Clear Interrupt flag   
        PieCtrlRegs.PIEACK.all=0x100;      // Issue PIE ack   
}

void Delay_1ms(long end)
{
    long i;
    for (i = 0; i <(9000 * end); i++);
}

Thanks in advance.

  • 0
    Guru 13185 points

    Hello,

    First of all, it should be  InitPieVectTable(); before this line:

    Rachit Jain said:
       // Interrupts that are used in this example are re-mapped to   
        // ISR functions found within this file.     
           EALLOW;  
           PieVectTable.RXBINT = &scibRxFifoIsr;      
           EDIS;  

    Like the example below from  C:\tidcs\c28\DSP281x\v120\DSP281x_examples\sci_loopback_interrupts

    // 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 DSP281x_DefaultIsr.c.
    // This function is found in DSP281x_PieVect.c.
       InitPieVectTable();

    // Interrupts that are used in this example are re-mapped to
    // ISR functions found within this file.
       EALLOW;    // This is needed to write to EALLOW protected registers
       PieVectTable.RXAINT = &sciaRxFifoIsr;
       PieVectTable.TXAINT = &sciaTxFifoIsr;
       PieVectTable.RXBINT = &scibRxFifoIsr;

    ...

    Please refer again this example to generate the interrupt and if it is still doesn't work, please let us know.

    Best regards,

    Maria

  • 0 in reply to Maria Todorova
    Intellectual 265 points

    I have added both the DSP281x_DefaultIsr.c and the  DSP281x_PieVect.c as it is. Also added the function  in between as you told ,but still there is no interrupt response.

     

    I'm trying to receive a "a" via the HyperTerminal and thus switch the GPIO pins low. Using SCI-B for that.

    Since there is only one character thus i have written the code as-

    ScibRegs.SCIFFRX.all=0x0021;

    and then i have set-

    ScibRegs.SCIFFRX.bit.RXFIFORESET=1;

    and i have enabled all the other signals-

     PieCtrlRegs.PIEIER9.bit.INTx3=1;

    IER = 0x100;

    thus the interrupt should flow smoothly and the B port should be set low. But this is not happening.

    Can you please help me out.

    Thank you

  • 0 in reply to Rachit Jain
    Guru 13185 points

    Hello,

    Please define SCIFFTX too, there is bit that used to enable the FIFO and also bit to reset the SCI.

    Best regards,

    Maria

  • 0 in reply to Rachit Jain
    Genius 3735 points

    Rachit,

    If you read the port by polling, do you get the characters?

    I found that I had to detect error conditions in my receive interrupt, as I would occasionally get a BREAK condition, and the only way to recover was to reset the UART.  Code:

    if (ScibRegs.SCIRXST.bit.RXERROR) {
    // Must reset device. First wait for XMIT to finish.
    while (ScibRegs.SCICTL2.bit.TXRDY == 0) ;

    // Now toggle software reset. This does not affect the configuration.
    ScibRegs.SCICTL1.bit.SWRESET = 0;
    ScibRegs.SCICTL1.bit.SWRESET = 1;
    }

  • 0 in reply to Maria Todorova
    Intellectual 265 points

    Maria,


    I am just trying to receive the  data. I am not exactly using the example code.

    The thing i want to do is receive a character at the receiver of the SCI-B and generate an interrupt that will ground the B port pins(B0 to B7).

    Is it necessary to initialize the SCIFFTX and other bits also when i am only using receiver part of the code?

    Thank You for your reply though.

  • 0 in reply to Bill Finger
    Intellectual 265 points

    Bill,

    I just added this code in the main part of the code-

     while(1)
         {
              rdataB=ScibRegs.SCIRXBUF.all;
              if ( ScibRegs.SCIRXST.bit.RXRDY == 1)
              {
                      for(;;);
                   
              }
         }

    This part is just before the "void main()" ending.

    The problem i figured is that the receiver pin is not receiving the data as the execution doesn't go in side the if part.

    Is there any initialization error or any other other silly error that i am making.

    Thank You for your reply though.

  • 0 in reply to Rachit Jain
    Expert 2570 points

    Rachit Jain, 

                  you can refer this link, This link has TMS320F2812 SCIB Uart code. 

    https://www.pantechsolutions.net/tms320f2812/problem-in-uart-of-tms320f2812-1/410.html#p410

    Many Thanks,

    Thiyagarajan.S

  • 0 in reply to Rachit Jain
    Intellectual 265 points

    I am getting a value of C09C in ScibRegs.SCIRXBUF.all. This means i am getting a framing and a parity error. So how do i tackle that.

  • 0 in reply to Rachit Jain
    Guru 192875 points

    Did you check on DSO, is the baud rate fine?

  • 0 in reply to Gautam Iyer
    Intellectual 265 points

    I have set the baud rate at 9600. I dont think there is any problem in the baud rate.

  • 0 in reply to Rachit Jain
    Guru 13185 points

    Rachit Jain said:
    Is it necessary to initialize the SCIFFTX

    Hello,

    I saw that you try to use FIFO (RXFIFO).

    How can you be able to use FIFO if you are not enable it?

    And to enable it, you should define the bit in SCIFFTX register (please see the picture below).

    I got this document from F28069, but I believe they are similar. Please check F2812 documentation for making it sure which bit you should set.

    Best regards,

    Maria

  • 0 in reply to Maria Todorova
    Intellectual 265 points

    Yes i already did that initialization. I wrote that later in the code though and that is why i am getting C09C value in the RXBUF i.e SCIFFFE and SCIFFPE are set.

  • 0 in reply to Rachit Jain
    Genius 3735 points

    Rachit,

    I take it you don't enable interrupts before going into this loop?

    Also, do you disable the watchdog somewhere?

    Regards,

    Bill

  • 0 in reply to Rachit Jain
    Guru 13185 points

    Aha, OK, so now the RX FIFO interrupt occurs, right? (only the value isn't like expected).

    Btw, I saw that you enable the loop back in your previous code (ScibRegs.SCICCR.bit.LOOPBKENA =1; // Enable loop back ). I think you enter the character from PC, is it right? If so, this bit should be 0.

    Best regards,

    Maria

  • 0 in reply to Maria Todorova
    Intellectual 265 points

    Ah! the code finally works and there is no better feeling.

    There was a one error in the loop and the loopback error.

    Thank you Maria

  • 0 in reply to Rachit Jain
    Guru 13185 points

    Oh, that's great! No better feeling indeed when our code works!

    Cheers!

    Best regards,

    Maria

  • 0 in reply to Rachit Jain
    Intellectual 375 points
    Hi Rachit,

    I'm encountering the same problem as yours now. Was hoping if you can tell me what you changed in your code to fix it?

    Thank you so much
  • 0 in reply to Kevin Darmasaputra
    TI__Mastermind 21305 points
    Please create a new thread if you would like further assistance on this issue. Your question has a better chance of being answered that way.