TMDSCNCD28335: Sampling Time ADC with Matlab Coder

The ADC on this device is capable of 12.5MSPS(80ns sample rate).  Would it be possible to post the C code that simulink generates based on the above block diagram?  There are a couple of factors here, both the sample and hold window that is set to the ADC, as well as the trigger source that simulink sets up to sample the signal.  I think it will be easier for me to see the output code to say exactly what is going on.  Perhaps the customer could post the code at 2us(working) and 1us(not working).

Best,

Matthew

Hello Matthew,

Here is the customer's response below.

Thank you in advance for your help. I have attached once the code for sampling time 2us and 1us. I was not sure if the main code is enough so I attached the whole exported code, I hope that’s no problem.

I don’t know if this additional information maybe helps:
The two separate GPIO’s are driving the two LED on the board which should blink with 0.5Hz. If I set the sampling time to 20us, I can see them blinking. Reducing the sample time to 2us, booth LED stay on (not switching very fast, I measured it).

Best regards,

Jonathan

Jonathan,
Did the customer send code to attach to the post?  I'm not seeing the attachment.

Best,

Matthew

Hello Matthew

Thank you very much for your help and sorry for the inconveniences with the communication. I had problems getting proper access to the forum.

I don't know if the main code is enough for you to tell something but i will start with that. Else I will be around now.

Best regards,

Marius

Working code with 2us sampling time:

/*
 * Academic License - for use in teaching, academic research, and meeting
 * course requirements at degree granting institutions only.  Not for
 * government, commercial, or other organizational use.
 *
 * File: Test_Sampling_Time.c
 *
 * Code generated for Simulink model 'Test_Sampling_Time'.
 *
 * Model version                  : 1.2
 * Simulink Coder version         : 9.5 (R2021a) 14-Nov-2020
 * C/C++ source code generated on : Fri Apr 29 11:13:56 2022
 *
 * Target selection: ert.tlc
 * Embedded hardware selection: Texas Instruments->C2000
 * Code generation objectives: Unspecified
 * Validation result: Not run
 */

#include "Test_Sampling_Time.h"
#include "Test_Sampling_Time_private.h"

/* Block signals (default storage) */
B_Test_Sampling_Time_T Test_Sampling_Time_B;

/* Block states (default storage) */
DW_Test_Sampling_Time_T Test_Sampling_Time_DW;

/* Real-time model */
static RT_MODEL_Test_Sampling_Time_T Test_Sampling_Time_M_;
RT_MODEL_Test_Sampling_Time_T *const Test_Sampling_Time_M =
  &Test_Sampling_Time_M_;
static void rate_monotonic_scheduler(void);
uint16_T MW_adcInitFlag = 0;

/*
 * Set which subrates need to run this base step (base rate always runs).
 * This function must be called prior to calling the model step function
 * in order to "remember" which rates need to run this base step.  The
 * buffering of events allows for overlapping preemption.
 */
void Test_Sampling_Time_SetEventsForThisBaseStep(boolean_T *eventFlags)
{
  /* Task runs when its counter is zero, computed via rtmStepTask macro */
  eventFlags[1] = ((boolean_T)rtmStepTask(Test_Sampling_Time_M, 1));
}

/*
 *   This function updates active task flag for each subrate
 * and rate transition flags for tasks that exchange data.
 * The function assumes rate-monotonic multitasking scheduler.
 * The function must be called at model base rate so that
 * the generated code self-manages all its subrates and rate
 * transition flags.
 */
static void rate_monotonic_scheduler(void)
{
  /* Compute which subrates run during the next base time step.  Subrates
   * are an integer multiple of the base rate counter.  Therefore, the subtask
   * counter is reset when it reaches its limit (zero means run).
   */
  (Test_Sampling_Time_M->Timing.TaskCounters.TID[1])++;
  if ((Test_Sampling_Time_M->Timing.TaskCounters.TID[1]) > 499999) {/* Sample time: [1.0s, 0.0s] */
    Test_Sampling_Time_M->Timing.TaskCounters.TID[1] = 0;
  }
}

/* Model step function for TID0 */
void Test_Sampling_Time_step0(void)    /* Sample time: [2.0E-6s, 0.0s] */
{
  {                                    /* Sample time: [2.0E-6s, 0.0s] */
    rate_monotonic_scheduler();
  }

  /* S-Function (c280xadc): '<Root>/Current_Meassurement' */
  {
    AdcRegs.ADCTRL2.bit.RST_SEQ1 = 1;  /* Reset SEQ1 module*/
    AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1;/*clear INT sequencer*/
    AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 1;  /* Software Trigger*/
    while (AdcRegs.ADCST.bit.INT_SEQ1 == 0) {
    }                                  /*Wait for Sequencer INT bit to clear */

    asm(" RPT #11 || NOP");
    Test_Sampling_Time_B.Current_Meassurement = (AdcRegs.ADCRESULT0) >> 4;
  }

  /* Switch: '<Root>/Switch' incorporates:
   *  Constant: '<Root>/Constant2'
   *  Gain: '<Root>/Gain'
   *  Gain: '<Root>/Gain1'
   *  Sum: '<Root>/Sum'
   */
  if (Test_Sampling_Time_P.Gain1_Gain *
      Test_Sampling_Time_B.Current_Meassurement * Test_Sampling_Time_P.Gain_Gain
      - Test_Sampling_Time_P.Constant2_Value >
      Test_Sampling_Time_P.Switch_Threshold) {
    /* Switch: '<Root>/Switch' incorporates:
     *  Constant: '<Root>/Constant'
     */
    Test_Sampling_Time_B.Switch = Test_Sampling_Time_P.Constant_Value;
  } else {
    /* Switch: '<Root>/Switch' incorporates:
     *  Constant: '<Root>/Constant1'
     */
    Test_Sampling_Time_B.Switch = Test_Sampling_Time_P.Constant1_Value;
  }

  /* End of Switch: '<Root>/Switch' */

  /* S-Function (c280xgpio_do): '<Root>/GPIO 02' */
  {
    if (Test_Sampling_Time_B.Switch)
      GpioDataRegs.GPASET.bit.GPIO2 = 1;
    else
      GpioDataRegs.GPACLEAR.bit.GPIO2 = 1;
  }
}

/* Model step function for TID1 */
void Test_Sampling_Time_step1(void)    /* Sample time: [1.0s, 0.0s] */
{
  /* DiscretePulseGenerator: '<Root>/Pulse Generator1' */
  Test_Sampling_Time_B.PulseGenerator1 = (Test_Sampling_Time_DW.clockTickCounter
    < Test_Sampling_Time_P.PulseGenerator1_Duty) &&
    (Test_Sampling_Time_DW.clockTickCounter >= 0L) ?
    Test_Sampling_Time_P.PulseGenerator1_Amp : 0.0;

  /* DiscretePulseGenerator: '<Root>/Pulse Generator1' */
  if (Test_Sampling_Time_DW.clockTickCounter >=
      Test_Sampling_Time_P.PulseGenerator1_Period - 1.0) {
    Test_Sampling_Time_DW.clockTickCounter = 0L;
  } else {
    Test_Sampling_Time_DW.clockTickCounter++;
  }

  /* S-Function (c280xgpio_do): '<Root>/LED 1' */
  {
    if (Test_Sampling_Time_B.PulseGenerator1)
      GpioDataRegs.GPASET.bit.GPIO31 = 1;
    else
      GpioDataRegs.GPACLEAR.bit.GPIO31 = 1;
  }

  /* Logic: '<Root>/NOT' */
  Test_Sampling_Time_B.NOT = !(Test_Sampling_Time_B.PulseGenerator1 != 0.0);

  /* S-Function (c280xgpio_do): '<Root>/LED2' */
  {
    if (Test_Sampling_Time_B.NOT)
      GpioDataRegs.GPBSET.bit.GPIO34 = 1;
    else
      GpioDataRegs.GPBCLEAR.bit.GPIO34 = 1;
  }
}

/* Model initialize function */
void Test_Sampling_Time_initialize(void)
{
  /* Registration code */

  /* initialize real-time model */
  (void) memset((void *)Test_Sampling_Time_M, 0,
                sizeof(RT_MODEL_Test_Sampling_Time_T));

  /* block I/O */
  (void) memset(((void *) &Test_Sampling_Time_B), 0,
                sizeof(B_Test_Sampling_Time_T));

  /* states (dwork) */
  (void) memset((void *)&Test_Sampling_Time_DW, 0,
                sizeof(DW_Test_Sampling_Time_T));

  /* Start for S-Function (c280xadc): '<Root>/Current_Meassurement' */
  if (MW_adcInitFlag == 0) {
    InitAdc();
    MW_adcInitFlag = 1;
  }

  config_ADC_A (0U, 0U, 0U, 0U, 0U);

  /* Start for S-Function (c280xgpio_do): '<Root>/GPIO 02' */
  EALLOW;
  GpioCtrlRegs.GPAMUX1.all &= 0xFFFFFFCF;
  GpioCtrlRegs.GPADIR.all |= 0x4;
  EDIS;

  /* Start for DiscretePulseGenerator: '<Root>/Pulse Generator1' */
  Test_Sampling_Time_DW.clockTickCounter = 0L;

  /* Start for S-Function (c280xgpio_do): '<Root>/LED 1' */
  EALLOW;
  GpioCtrlRegs.GPAMUX2.all &= 0x3FFFFFFF;
  GpioCtrlRegs.GPADIR.all |= 0x80000000;
  EDIS;

  /* Start for S-Function (c280xgpio_do): '<Root>/LED2' */
  EALLOW;
  GpioCtrlRegs.GPBMUX1.all &= 0xFFFFFFCF;
  GpioCtrlRegs.GPBDIR.all |= 0x4;
  EDIS;
}

/* Model terminate function */
void Test_Sampling_Time_terminate(void)
{
  /* (no terminate code required) */
}

/*
 * File trailer for generated code.
 *
 * [EOF]
 */

Not working code with 1us sampling time:

/*
 *
 * File: Test_Sampling_Time.c
 *
 * Code generated for Simulink model 'Test_Sampling_Time'.
 *
 * Model version                  : 1.2
 * Simulink Coder version         : 9.5 (R2021a) 14-Nov-2020
 * C/C++ source code generated on : Fri Apr 29 11:12:24 2022
 *
 * Target selection: ert.tlc
 * Embedded hardware selection: Texas Instruments->C2000
 * Code generation objectives: Unspecified
 * Validation result: Not run
 */

#include "Test_Sampling_Time.h"
#include "Test_Sampling_Time_private.h"

/* Block signals (default storage) */
B_Test_Sampling_Time_T Test_Sampling_Time_B;

/* Block states (default storage) */
DW_Test_Sampling_Time_T Test_Sampling_Time_DW;

/* Real-time model */
static RT_MODEL_Test_Sampling_Time_T Test_Sampling_Time_M_;
RT_MODEL_Test_Sampling_Time_T *const Test_Sampling_Time_M =
  &Test_Sampling_Time_M_;
static void rate_monotonic_scheduler(void);
uint16_T MW_adcInitFlag = 0;

/*
 * Set which subrates need to run this base step (base rate always runs).
 * This function must be called prior to calling the model step function
 * in order to "remember" which rates need to run this base step.  The
 * buffering of events allows for overlapping preemption.
 */
void Test_Sampling_Time_SetEventsForThisBaseStep(boolean_T *eventFlags)
{
  /* Task runs when its counter is zero, computed via rtmStepTask macro */
  eventFlags[1] = ((boolean_T)rtmStepTask(Test_Sampling_Time_M, 1));
}

/*
 *   This function updates active task flag for each subrate
 * and rate transition flags for tasks that exchange data.
 * The function assumes rate-monotonic multitasking scheduler.
 * The function must be called at model base rate so that
 * the generated code self-manages all its subrates and rate
 * transition flags.
 */
static void rate_monotonic_scheduler(void)
{
  /* Compute which subrates run during the next base time step.  Subrates
   * are an integer multiple of the base rate counter.  Therefore, the subtask
   * counter is reset when it reaches its limit (zero means run).
   */
  (Test_Sampling_Time_M->Timing.TaskCounters.TID[1])++;
  if ((Test_Sampling_Time_M->Timing.TaskCounters.TID[1]) > 999999) {/* Sample time: [1.0s, 0.0s] */
    Test_Sampling_Time_M->Timing.TaskCounters.TID[1] = 0;
  }
}

/* Model step function for TID0 */
void Test_Sampling_Time_step0(void)    /* Sample time: [1.0E-6s, 0.0s] */
{
  {                                    /* Sample time: [1.0E-6s, 0.0s] */
    rate_monotonic_scheduler();
  }

  /* S-Function (c280xadc): '<Root>/Current_Meassurement' */
  {
    AdcRegs.ADCTRL2.bit.RST_SEQ1 = 1;  /* Reset SEQ1 module*/
    AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1;/*clear INT sequencer*/
    AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 1;  /* Software Trigger*/
    while (AdcRegs.ADCST.bit.INT_SEQ1 == 0) {
    }                                  /*Wait for Sequencer INT bit to clear */

    asm(" RPT #11 || NOP");
    Test_Sampling_Time_B.Current_Meassurement = (AdcRegs.ADCRESULT0) >> 4;
  }

  /* Switch: '<Root>/Switch' incorporates:
   *  Constant: '<Root>/Constant2'
   *  Gain: '<Root>/Gain'
   *  Gain: '<Root>/Gain1'
   *  Sum: '<Root>/Sum'
   */
  if (Test_Sampling_Time_P.Gain1_Gain *
      Test_Sampling_Time_B.Current_Meassurement * Test_Sampling_Time_P.Gain_Gain
      - Test_Sampling_Time_P.Constant2_Value >
      Test_Sampling_Time_P.Switch_Threshold) {
    /* Switch: '<Root>/Switch' incorporates:
     *  Constant: '<Root>/Constant'
     */
    Test_Sampling_Time_B.Switch = Test_Sampling_Time_P.Constant_Value;
  } else {
    /* Switch: '<Root>/Switch' incorporates:
     *  Constant: '<Root>/Constant1'
     */
    Test_Sampling_Time_B.Switch = Test_Sampling_Time_P.Constant1_Value;
  }

  /* End of Switch: '<Root>/Switch' */

  /* S-Function (c280xgpio_do): '<Root>/GPIO 02' */
  {
    if (Test_Sampling_Time_B.Switch)
      GpioDataRegs.GPASET.bit.GPIO2 = 1;
    else
      GpioDataRegs.GPACLEAR.bit.GPIO2 = 1;
  }
}

/* Model step function for TID1 */
void Test_Sampling_Time_step1(void)    /* Sample time: [1.0s, 0.0s] */
{
  /* DiscretePulseGenerator: '<Root>/Pulse Generator1' */
  Test_Sampling_Time_B.PulseGenerator1 = (Test_Sampling_Time_DW.clockTickCounter
    < Test_Sampling_Time_P.PulseGenerator1_Duty) &&
    (Test_Sampling_Time_DW.clockTickCounter >= 0L) ?
    Test_Sampling_Time_P.PulseGenerator1_Amp : 0.0;

  /* DiscretePulseGenerator: '<Root>/Pulse Generator1' */
  if (Test_Sampling_Time_DW.clockTickCounter >=
      Test_Sampling_Time_P.PulseGenerator1_Period - 1.0) {
    Test_Sampling_Time_DW.clockTickCounter = 0L;
  } else {
    Test_Sampling_Time_DW.clockTickCounter++;
  }

  /* S-Function (c280xgpio_do): '<Root>/LED 1' */
  {
    if (Test_Sampling_Time_B.PulseGenerator1)
      GpioDataRegs.GPASET.bit.GPIO31 = 1;
    else
      GpioDataRegs.GPACLEAR.bit.GPIO31 = 1;
  }

  /* Logic: '<Root>/NOT' */
  Test_Sampling_Time_B.NOT = !(Test_Sampling_Time_B.PulseGenerator1 != 0.0);

  /* S-Function (c280xgpio_do): '<Root>/LED2' */
  {
    if (Test_Sampling_Time_B.NOT)
      GpioDataRegs.GPBSET.bit.GPIO34 = 1;
    else
      GpioDataRegs.GPBCLEAR.bit.GPIO34 = 1;
  }
}

/* Model initialize function */
void Test_Sampling_Time_initialize(void)
{
  /* Registration code */

  /* initialize real-time model */
  (void) memset((void *)Test_Sampling_Time_M, 0,
                sizeof(RT_MODEL_Test_Sampling_Time_T));

  /* block I/O */
  (void) memset(((void *) &Test_Sampling_Time_B), 0,
                sizeof(B_Test_Sampling_Time_T));

  /* states (dwork) */
  (void) memset((void *)&Test_Sampling_Time_DW, 0,
                sizeof(DW_Test_Sampling_Time_T));

  /* Start for S-Function (c280xadc): '<Root>/Current_Meassurement' */
  if (MW_adcInitFlag == 0) {
    InitAdc();
    MW_adcInitFlag = 1;
  }

  config_ADC_A (0U, 0U, 0U, 0U, 0U);

  /* Start for S-Function (c280xgpio_do): '<Root>/GPIO 02' */
  EALLOW;
  GpioCtrlRegs.GPAMUX1.all &= 0xFFFFFFCF;
  GpioCtrlRegs.GPADIR.all |= 0x4;
  EDIS;

  /* Start for DiscretePulseGenerator: '<Root>/Pulse Generator1' */
  Test_Sampling_Time_DW.clockTickCounter = 0L;

  /* Start for S-Function (c280xgpio_do): '<Root>/LED 1' */
  EALLOW;
  GpioCtrlRegs.GPAMUX2.all &= 0x3FFFFFFF;
  GpioCtrlRegs.GPADIR.all |= 0x80000000;
  EDIS;

  /* Start for S-Function (c280xgpio_do): '<Root>/LED2' */
  EALLOW;
  GpioCtrlRegs.GPBMUX1.all &= 0xFFFFFFCF;
  GpioCtrlRegs.GPBDIR.all |= 0x4;
  EDIS;
}

/* Model terminate function */
void Test_Sampling_Time_terminate(void)
{
  /* (no terminate code required) */
}

/*
 * File trailer for generated code.
 *
 * [EOF]
 */

Thanks for posting this, something in the function rate_monotonic_scheduler doesn't make sense to me, in the 2us version the counter for the loop is 499999. whereas for 1us it is 999999.  I would think that the 1us should be half the 2us, not double.  Both numbers are >16-bits so I don't think there is a casting issue.

I will see if the MW team can give some insight as to what exactly is going on with the timer function and how it is eventually calling the ADC SOC.

Best,

Matthew

Hi Jonathan,

Could you share the model to help us reproduce the issue?

Best Regards,

Ram Alla | MathWorks

Test_Sampling_Time.zip

Dear Ram, thank you for your response.

Thank you for your response, I am the costumer in whose behalf Jonathan posted this issue. I have attached the model to this message.

Best Regards,

Marius