STM32H723 ADC read stuck (using LL libraries)

[Linas L]

Hello,
In my project I just sometimes need to read ADC values. I figure I could simply connect two of my signals to ADC1 and ADC2 respectively.

What it strange that it does sometimes working, but sometimes it is stuck at constant value ( maybe first read i think)

ADC is clocked from PLL at 100MHz

void ADC_Init(void)
{
  uint32_t timeout = 0xFFFFF;

  LL_ADC_InitTypeDef ADC_InitStruct = {0};
  LL_ADC_REG_InitTypeDef ADC_REG_InitStruct = {0};
  LL_ADC_CommonInitTypeDef ADC_CommonInitStruct = {0};

  LL_GPIO_InitTypeDef GPIO_InitStruct = {0};

  LL_RCC_SetADCClockSource(LL_RCC_ADC_CLKSOURCE_PLL3R);

  LL_AHB1_GRP1_EnableClock(LL_AHB1_GRP1_PERIPH_ADC12);

  GPIO_InitStruct.Pin = LL_GPIO_PIN_11|LL_GPIO_PIN_13;
  GPIO_InitStruct.Mode = LL_GPIO_MODE_ANALOG;
  GPIO_InitStruct.Pull = LL_GPIO_PULL_NO;
  LL_GPIO_Init(GPIOF, &GPIO_InitStruct);


  LL_ADC_SetOverSamplingScope(ADC1, LL_ADC_OVS_GRP_REGULAR_CONTINUED);
  LL_ADC_ConfigOverSamplingRatioShift(ADC1, 1024, LL_ADC_OVS_SHIFT_RIGHT_6);
  LL_ADC_SetOverSamplingDiscont(ADC1, LL_ADC_OVS_REG_CONT);

  LL_ADC_SetOverSamplingScope(ADC2, LL_ADC_OVS_GRP_REGULAR_CONTINUED);
  LL_ADC_ConfigOverSamplingRatioShift(ADC2, 1024, LL_ADC_OVS_SHIFT_RIGHT_6);
  LL_ADC_SetOverSamplingDiscont(ADC2, LL_ADC_OVS_REG_CONT);


  ADC_InitStruct.Resolution = LL_ADC_RESOLUTION_16B;
  ADC_InitStruct.LowPowerMode = LL_ADC_LP_MODE_NONE;

  LL_ADC_Init(ADC1, &ADC_InitStruct);
  LL_ADC_Init(ADC2, &ADC_InitStruct);

  ADC_REG_InitStruct.TriggerSource = LL_ADC_REG_TRIG_SOFTWARE;
  ADC_REG_InitStruct.SequencerLength = LL_ADC_REG_SEQ_SCAN_DISABLE;
  ADC_REG_InitStruct.SequencerDiscont = DISABLE;
  ADC_REG_InitStruct.ContinuousMode = LL_ADC_REG_CONV_CONTINUOUS;
  ADC_REG_InitStruct.Overrun = LL_ADC_REG_OVR_DATA_PRESERVED;

  LL_ADC_REG_Init(ADC1, &ADC_REG_InitStruct);
  LL_ADC_REG_Init(ADC2, &ADC_REG_InitStruct);


  ADC_CommonInitStruct.CommonClock = LL_ADC_CLOCK_ASYNC_DIV1;
  ADC_CommonInitStruct.Multimode = LL_ADC_MULTI_INDEPENDENT;

  LL_ADC_CommonInit(__LL_ADC_COMMON_INSTANCE(ADC1), &ADC_CommonInitStruct);
  LL_ADC_CommonInit(__LL_ADC_COMMON_INSTANCE(ADC2), &ADC_CommonInitStruct);

  LL_ADC_DisableDeepPowerDown(ADC1);
  LL_ADC_DisableDeepPowerDown(ADC2);

  LL_ADC_EnableInternalRegulator(ADC1);
  LL_ADC_EnableInternalRegulator(ADC2);

  Delay(0xFFFF);

  LL_ADC_StartCalibration(ADC1,LL_ADC_CALIB_OFFSET_LINEARITY,LL_ADC_SINGLE_ENDED);
  LL_ADC_StartCalibration(ADC2,LL_ADC_CALIB_OFFSET_LINEARITY,LL_ADC_SINGLE_ENDED);

  timeout = 0xFFFFF;
  while(LL_ADC_IsCalibrationOnGoing(ADC1)!=0)
  {
    timeout--;
    if(timeout==0)
    {
      break;
    }
  }
  timeout = 0xFFFFF;
  while(LL_ADC_IsCalibrationOnGoing(ADC2)!=0)
  {
    timeout--;
    if(timeout==0)
    {
      break;
    }
  }

  LL_ADC_REG_SetSequencerRanks(ADC1, LL_ADC_REG_RANK_1, LL_ADC_CHANNEL_2);
  LL_ADC_SetChannelSamplingTime(ADC1, LL_ADC_CHANNEL_2, LL_ADC_SAMPLINGTIME_16CYCLES_5);
  LL_ADC_SetChannelSingleDiff(ADC1, LL_ADC_CHANNEL_2, LL_ADC_SINGLE_ENDED);
  LL_ADC_SetChannelPreselection(ADC1, LL_ADC_CHANNEL_2);

  LL_ADC_REG_SetSequencerRanks(ADC2, LL_ADC_REG_RANK_1, LL_ADC_CHANNEL_2);
  LL_ADC_SetChannelSamplingTime(ADC2, LL_ADC_CHANNEL_2, LL_ADC_SAMPLINGTIME_16CYCLES_5);
  LL_ADC_SetChannelSingleDiff(ADC2, LL_ADC_CHANNEL_2, LL_ADC_SINGLE_ENDED);
  LL_ADC_SetChannelPreselection(ADC2, LL_ADC_CHANNEL_2);

  LL_ADC_Enable(ADC1);
  LL_ADC_Enable(ADC2);

  timeout = 0xFFFFF;
  while (LL_ADC_IsActiveFlag_ADRDY(ADC1) == 0UL)
  {
    timeout--;
    if(timeout==0)
    {
      break;
    }
  }
  timeout = 0xFFFFF;
   while (LL_ADC_IsActiveFlag_ADRDY(ADC2) == 0UL)
  {
    timeout--;
    if(timeout==0)
    {
      break;
    }
  }
  LL_ADC_REG_StartConversion(ADC1);
  LL_ADC_REG_StartConversion(ADC2);
}

uint16_t ADC_READ_IN1(void)
{
    return (ADC2->DR)>>4;
}
uint16_t ADC_READ_IN2(void)
{
  return (ADC1->DR)>>4;
}

So I have two question:
Does any one can spot a problem, or tell my why I simply can't read ADC->DR register  if i am running only single channel per ADC ?

Thank you !
Any

[raptorhal2 · Accepted solution]

I checked the H725 Data sheet and the ADCs are limited to 50 and 75 MHz. Check the H723 data sheet for maximum ADC frequency.

[AScha.3]

50MHz max.

see:

[Linas L]

Hello,
Thanks for pointing this out, CubeMX did allowed me to config it for 100MHz, while adding divider helped and now it's working ! I even did not checked it for clock, since 100MHz does not look too high and code was generated by software that does indicate values out of spec.

[Amel NASRI]

Hi @Linas L ,

Glad to know that your problem is resolved.
To fix the issue on STM32CubeMX side, could you please:

• confirm that issue is faced with latest version of STM32CubeMX (6.9.0)
• share your ioc file so that I can reproduce the problem with exact configuration on my side

-Amel