Data missing from SSI via DMA.

Srinivasa Wunnimani

Other Parts Discussed in Thread: TM4C129ENCPDT

Hi,

I have configured SSI to get data from DMA and I have attached the code for reference. Sometimes I am observing that I am missing data in DMABuffer. My data contains sequence number which can be validated but its missing in DMABuffer.

I have conducted a test as below:

I had made sure that DMABuffer is not accessed and modified elsewhere I have commented other part of code and had it only in interrupt (SSI0_dma_int). If I run the code for some time and watch this buffer in watch window I am seeing that some data missing.

DMABuffer buffer will be filled only by DMA and why it is not in proper order?

Regards

Fullscreen 8357.spiDMA_pseudoCode.c Download

/*
  DMA is Inialized on power up.
*/

void initDMA (void)
{
    Error_Block eb;
    Hwi_Params  hwiParams;
    ULONG lnTemp;

    if(!DMA_initialized){

        Error_init(&eb);

        Hwi_Params_init(&hwiParams);
        Hwi_construct(&(hwiStruct), INT_UDMAERR, errorDMAHwi,
                      &hwiParams, &eb);
        if (Error_check(&eb)) {
            System_abort("Couldn't construct DMA error hwi");
        }

        SysCtlPeripheralEnable(SYSCTL_PERIPH_UDMA);
        uDMAEnable();

        uDMAControlBaseSet(DMAControlTable);

        DMA_initialized = TRUE;
    }
}


power_up_init()
{

  /*
  On power up, GPIOs are configured.
  */



  // *** SSI Module(FLASH) ***
  MAP_GPIOPinConfigure(GPIO_PA2_SSI0CLK);
  MAP_GPIOPinConfigure(GPIO_PA3_SSI0FSS);
  MAP_GPIOPinConfigure(GPIO_PA4_SSI0XDAT0);
  MAP_GPIOPinConfigure(GPIO_PA5_SSI0XDAT1);


  // Configure the GPIO pins for the SSI module
  MAP_GPIOPinTypeSSI(GPIO_PORTA_BASE, GPIO_PIN_2 | GPIO_PIN_3 | GPIO_PIN_4 | GPIO_PIN_5);
}


/*

This function is called after power up routines.
During power up, SPI0 is working fine, its reading data from flash.
We change SPI0 from master to slave and want to read data from SSI0 using DMA.
*/


void run_time()
{

    /* On power on I am having same SPI configured as Master
       hence, closing it and later configuring as slave..

       On power on we are reading data from FLASH, it is working fine.
       but here we are not using DMA.
    */
    SPI_close(spiHandles[TM4C129X_SPI0]);


    /* Reset the SPI */
    lnTemp = HWREG(SYSCTL_BASE + 0x51C);
    lnTemp = (lnTemp | SYSCTL_SRSSI_R0);
    HWREG(SYSCTL_BASE + 0x51C) = lnTemp;

    lnTemp = HWREG(SYSCTL_BASE + 0x51C);
    lnTemp = (lnTemp & ~(SYSCTL_SRSSI_R0) );
    HWREG(SYSCTL_BASE + 0x51C) = lnTemp;

    while ((HWREG(SYSCTL_BASE + 0xA1C) & SYSCTL_PRSSI_R0) == 0);


    SPI_init();

    SPI_Params_init(&params);

    params.dataSize     = 16;
    params.mode         = SPI_SLAVE;

    params.transferMode = SPI_MODE_CALLBACK;

    params.bitRate      = 10000000;
    params.frameFormat  = SPI_POL1_PHA1;

    params.transferCallbackFxn = UserCallbackFxn;

    spiHandles[TM4C129X_SPI0] = SPI_open(TM4C129X_SPI0, &params);

    if (spiHandles[TM4C129X_SPI0] == NULL) {
      System_abort("Error initializing SPI\n");
    }
    else {
      System_printf("SPI 0 initialized\n");
    }


    MAP_GPIOPinTypeSSI(SSI_CS_GPIO_BASE, SSI_CS);

    IntDisable(SSI_MODULE_INT);

    SSIDisable(SSI_MODULE_BASE);

    SSIConfigSetExpClk(SSI_MODULE_BASE, 120000000 /* SysCtlClockGet() */, SSI_FRF_MOTO_MODE_1,
        SSI_MODE_SLAVE_OD, 6250000, 16);

    IntEnable(SSI_MODULE_INT);

    SSIDMAEnable(SSI_MODULE_BASE, SSI_DMA_RX);

    SSIEnable(SSI_MODULE_BASE);


    initDMA_control_table();

    SPI_Master = FALSE;  // Set a global variable to indicate that SPI slave inialization is complete.
    /*
    SPI initialization is done.
    */
}



/*
This is my slave task.

*/

void SPI_slave_t(void)
{

    /* Sleep till SPI is configured as Master */
    while(SPI_Master == TRUE)
    {
        Task_sleep(100);
    }

    while (1)
    {
        /* Doing a dummy write to clear SSI data register.*/
        transferOK = SPI_transfer(spiHandles[TM4C129X_SPI0], &slaveTransaction);
        dummyWrite++;


        /*
        Wait for data from DMA.
        */
        Semaphore_pend(SEM_dma_data, BIOS_WAIT_FOREVER);

        /*
        Process the data.
        */


    }
}




SPI_Callback UserCallbackFxn(SPI_Handle handle, SPI_Transaction * transaction)
{
  callbackCount++;

  /*
  I have a brekpoint at below printf statement,

  Immediately after initiating transfer from MASTER, control comes to this statment and stops.
  */
  System_printf("I am at %s\n", __FUNCTION__);


  /*
  If I enable this SSI0_dma_int(), system crashes.
  */


  SSI0_dma_int();


  return 0;
}




/*
Function to configure the ping pong mode and initiate DMA transfer.
*/

#define DAQ_BUFFER_PAGES           2
#define DAQ_BUFFER_PAGE_SZ_WORDS   160

UWORD DMABuffer[BUFFER_PAGES][BUFFER_PAGE_SZ_WORDS];


void SSI0_dma_int(void)
{
  ULONG ulMode;
  #define BUFFER_PAGE_SZ_WORDS   160

  //check primary channel
  ulMode = MAP_uDMAChannelModeGet(UDMA_CHANNEL_SSI0RX | UDMA_PRI_SELECT);
  if(ulMode == UDMA_MODE_STOP)
  {
    // Swap active and background pages
    ActivePage = 1;
    BgPage = 0;
    MAP_uDMAChannelTransferSet(UDMA_CHANNEL_SSI0RX | UDMA_PRI_SELECT, UDMA_MODE_PINGPONG, (void *)(SSI0_BASE + SSI_O_DR), &DMABuffer[0][0], BUFFER_PAGE_SZ_WORDS);
    MAP_uDMAChannelEnable(UDMA_CHANNEL_SSI0RX);
    DMAtransferCount++;
  }

  //check alt channel
  ulMode = MAP_uDMAChannelModeGet(UDMA_CHANNEL_SSI0RX | UDMA_ALT_SELECT);
  if(ulMode == UDMA_MODE_STOP) {
    // Swap active and background pages
    ActivePage = 0;
    BgPage = 1;
    MAP_uDMAChannelTransferSet(UDMA_CHANNEL_SSI0RX | UDMA_ALT_SELECT, UDMA_MODE_PINGPONG, (void *)(SSI0_BASE + SSI_O_DR), &DMABuffer[1][0], BUFFER_PAGE_SZ_WORDS);
    MAP_uDMAChannelEnable(UDMA_CHANNEL_SSI0RX);
    DMAtransferCount++;
  }

   Semaphore_post(SEM_dma_data);
}





void initDMA_control_table(void)
{
    ULONG lnTemp;
  debug_count++;

    MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_UDMA);

    uDMAEnable();

    MAP_uDMAControlBaseSet(&ucControlTable[0]);

    MAP_uDMAChannelAttributeDisable(UDMA_CHANNEL_SSI0RX, UDMA_ATTR_USEBURST | UDMA_ATTR_REQMASK );
    MAP_uDMAChannelAttributeDisable(UDMA_CHANNEL_SSI0RX, UDMA_ATTR_ALTSELECT | UDMA_ATTR_USEBURST | UDMA_ATTR_REQMASK );

    MAP_uDMAChannelAttributeEnable(UDMA_CHANNEL_SSI0RX, UDMA_ATTR_HIGH_PRIORITY);
    //MAP_uDMAChannelAttributeEnable(UDMA_CHANNEL_SSI0RX, UDMA_ATTR_HIGH_PRIORITY | UDMA_ATTR_ALTSELECT);

    // Primary Channel
    MAP_uDMAChannelControlSet(UDMA_CHANNEL_SSI0RX | UDMA_PRI_SELECT, UDMA_SIZE_16 | UDMA_SRC_INC_NONE | UDMA_DST_INC_16 | UDMA_ARB_8);
    MAP_uDMAChannelTransferSet(UDMA_CHANNEL_SSI0RX | UDMA_PRI_SELECT, UDMA_MODE_PINGPONG, (void *)(SSI0_BASE + SSI_O_DR), &DMABuffer[0][0], DAQ_BUFFER_PAGE_SZ_WORDS);

    // Alternate Channel
    MAP_uDMAChannelControlSet(UDMA_CHANNEL_SSI0RX | UDMA_ALT_SELECT, UDMA_SIZE_16 | UDMA_SRC_INC_NONE | UDMA_DST_INC_16 | UDMA_ARB_8);
    MAP_uDMAChannelTransferSet(UDMA_CHANNEL_SSI0RX | UDMA_ALT_SELECT, UDMA_MODE_PINGPONG, (void *)(SSI0_BASE + SSI_O_DR), &DMABuffer[1][0], DAQ_BUFFER_PAGE_SZ_WORDS);

    MAP_uDMAChannelEnable(UDMA_CHANNEL_SSI0RX);

}





void SSI0_dma_int(void)
{
  ULONG ulMode;
  MAIL_BOX_t dmaInfo;


    if( ActivePage == 0) {

        //check alt channel
        ulMode = MAP_uDMAChannelModeGet(UDMA_CHANNEL_SSI0RX | UDMA_ALT_SELECT);

        if(ulMode == UDMA_MODE_STOP) {

        // Swap active and background pages
        ActivePage = 1;
        alternateBufferCounter++;
        MAP_uDMAChannelTransferSet(UDMA_CHANNEL_SSI0RX | UDMA_ALT_SELECT, UDMA_MODE_PINGPONG, (void *)(SSI0_BASE + SSI_O_DR), &DMABuffer[1][0], DAQ_BUFFER_PAGE_SZ_WORDS);

        MAP_uDMAChannelEnable(UDMA_CHANNEL_SSI0RX);
        dmaInfo.bufferNumber = 1;
        }

      } else if(ActivePage == 1) {

        //check primary channel
        ulMode = MAP_uDMAChannelModeGet(UDMA_CHANNEL_SSI0RX | UDMA_PRI_SELECT);

        if(ulMode == UDMA_MODE_STOP)  {
          // Swap active and background pages
          ActivePage = 0;
          primaryBufferCounter++;
          MAP_uDMAChannelTransferSet(UDMA_CHANNEL_SSI0RX | UDMA_PRI_SELECT, UDMA_MODE_PINGPONG, (void *)(SSI0_BASE + SSI_O_DR), &DMABuffer[0][0], DAQ_BUFFER_PAGE_SZ_WORDS);

          MAP_uDMAChannelEnable(UDMA_CHANNEL_SSI0RX);
        }

        dmaInfo.bufferNumber = 0;
      }


      Mailbox_post(Mailbox_weld_daq, &dmaInfo, BIOS_NO_WAIT);

}

Srinivasa

over 10 years ago

0 David Friedland over 10 years ago

TI__Mastermind 18320 points

This doesn't appear to really be a TI-RTOS related query.
What device are you running on?

0 Tom Kopriva over 10 years ago

TI__Mastermind 20480 points

Is this using the TI-RTOS SPI driver or are you using driverlib directly? What device are you using? On Tiva devices, TI-RTOS has a spi loopback example that you can refer to. If you are using driverlib, TivaWare probably has some SPI examples.

0 Srinivasa Wunnimani over 10 years ago in reply to Tom Kopriva

Intellectual 790 points

My code uses uses driverlib directly.

Part number used: TIVA TM4C129ENCPDT

TI-RTOS Version: 1_21_00_09.

SSI examples provided in driverlib does not use DMA. I am having problem with SSI with DMA in PING-Pong mode.

Analysis methodology:

After a short run in debug mode, we are stopping the debugger and monitoring the DMABuffer. Comparing received data with the pattern of data that we are supposed to receive we are noticing some missing data in DMABuffer. To ensure that no other task is modifying this buffer we have commented the other parts of code where this buffer is read but still the same behavior and below details are also good.

Master clock is good and it is as expected at 6.25 MHz.
Data to Tiva processor is monitored and it is good.
Interrupt to Tiva processor is at expected rate of 1 milliseconds.

Regards

Srinivasa

0 David Friedland over 10 years ago in reply to Srinivasa Wunnimani

TI__Mastermind 18320 points

Srinivasa,

I went ahead and moved this thread over to the device forum in hopes that you will get a faster response there.

0 Amit Ashara over 10 years ago in reply to Srinivasa Wunnimani

TI__Guru**** 244400 points

Hello Srinivasa,

First of all the TI RTOS version being used is a very old version and may be so is the TivaWare in the same.

Secondly, if you run the same in TivaWare w/o any RTOS does it still occur?

Regards
Amit

0 Srinivasa Wunnimani over 10 years ago in reply to Amit Ashara

Intellectual 790 points

Hi Amit,

TI-RTOS Version: 1_21_00_09.

Tivaware: TivaWare_C_Series-2.0.1.11577a

I haven't tried with TivaWare only without RTOS.

Regards

Srinivasa

0 Amit Ashara over 10 years ago in reply to Srinivasa Wunnimani

TI__Guru**** 244400 points

Hello Srinivasa,

Yes, it is old version. The current version of TivaWare is 2.1.1. Also there may be updates to the TI-RTOS drivers that i suspect would have a major impact.

To simplify the issue, I would request you to create a small project with TivaWare only to reproduce the issue.

Regards
Amit

0 Srinivasa Wunnimani over 10 years ago in reply to Amit Ashara

Intellectual 790 points

Hi Amit,

It’s a good idea to create a project with TivaWare only but it may not be feasible in our case because I need to configure the peripheral (i.e DSP) but all the configuration parameters comes via Ethernet and without sending proper configuration, DSP will not send data on SPI.

If I remove RTOS, I think I won’t be having NDK and hence the Ethernet. Is there any other way of isolating this issue?

Regards
Srinivasa

0 Amit Ashara over 10 years ago in reply to Srinivasa Wunnimani

TI__Guru**** 244400 points

Hello Srinivasa

You can run the SSI in internal loopback mode and send the data from the SSI TX to RX pin to trigger the DMA function.

Regards
Amit

0 Srinivasa Wunnimani over 10 years ago in reply to Amit Ashara

Intellectual 790 points

Hello Amit,

That's great. Will try that and update you on that.

Regards
Srinivasa

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Data missing from SSI via DMA.