HAL_ADC_PollForConversion gets stuck

[dfshea]

I'm writing software that involves reading a single ADC value from my STM32H7R3V8H6, however it is getting stuck in HAL_ADC_PollForConversion(&hadc1, HAL_MAX_DELAY);.

If i switch the delay to a smaller value it runs through but it still returns a timeout.

while (1)
  {
		HAL_ADC_Start(&hadc1);
		HAL_ADC_PollForConversion(&hadc1, 100);
		adc1Data = HAL_ADC_GetValue(&hadc1);
		HAL_ADC_Stop(&hadc1);
		//readT(&engine, 0);
		//readP(&engine, 0);
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }

static void MX_ADC1_Init(void)
{

  /* USER CODE BEGIN ADC1_Init 0 */

  /* USER CODE END ADC1_Init 0 */

  ADC_MultiModeTypeDef multimode = {0};
  ADC_ChannelConfTypeDef sConfig = {0};

  /* USER CODE BEGIN ADC1_Init 1 */

  /* USER CODE END ADC1_Init 1 */

  /** Common config
  */
  hadc1.Instance = ADC1;
  hadc1.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;
  hadc1.Init.Resolution = ADC_RESOLUTION_12B;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.ScanConvMode = ADC_SCAN_DISABLE;
  hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  hadc1.Init.LowPowerAutoWait = DISABLE;
  hadc1.Init.ContinuousConvMode = DISABLE;
  hadc1.Init.NbrOfConversion = 1;
  hadc1.Init.DiscontinuousConvMode = DISABLE;
  hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
  hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
  hadc1.Init.SamplingMode = ADC_SAMPLING_MODE_NORMAL;
  hadc1.Init.ConversionDataManagement = ADC_CONVERSIONDATA_DR;
  hadc1.Init.Overrun = ADC_OVR_DATA_PRESERVED;
  hadc1.Init.OversamplingMode = DISABLE;
  if (HAL_ADC_Init(&hadc1) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure the ADC multi-mode
  */
  multimode.Mode = ADC_MODE_INDEPENDENT;
  if (HAL_ADCEx_MultiModeConfigChannel(&hadc1, &multimode) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure Regular Channel
  */
  sConfig.Channel = ADC_CHANNEL_0;
  sConfig.Rank = ADC_REGULAR_RANK_1;
  sConfig.SamplingTime = ADC_SAMPLETIME_2CYCLES_5;
  sConfig.SingleDiff = ADC_SINGLE_ENDED;
  sConfig.OffsetNumber = ADC_OFFSET_NONE;
  sConfig.Offset = 0;
  sConfig.OffsetSign = ADC_OFFSET_SIGN_NEGATIVE;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN ADC1_Init 2 */

  /* USER CODE END ADC1_Init 2 */

}

[Karl Yamashita]

HAL_MAX_DELAY = 49.7 Days! 

So if you wait for almost 50 days, the function will eventually return.

Typically 100ms is more than enough for a timeout.

How do you know if it return a timeout? You're not checking the return value.

HAL_StatusTypeDef hal_status = HAL_ADC_PollForConversion(&hadc1, 100);
	if(hal_status == HAL_ERROR)
	{
		// error handler
	}
	else if(hal_status == HAL_TIMEOUT)
	{
		// timeout handler
	}
	// get adc value

[dfshea]

Hm, 50 days is a bit much to see if it times out, so I reduced the delay to 100ms and added a return variable and confirmed that it is indeed returning HAL_TIMEOUT. 

I also did some digging and found where in the function it's getting stuck:

  tickstart = HAL_GetTick();

  /* Wait until End of unitary conversion or sequence conversions flag is raised */
  while ((hadc->Instance->ISR & tmp_Flag_End) == 0UL)
  {
    /* Check if timeout is disabled (set to infinite wait) */
    if (Timeout != HAL_MAX_DELAY)
    {
      if (((HAL_GetTick() - tickstart) > Timeout) || (Timeout == 0UL))
      {
        /* New check to avoid false timeout detection in case of preemption */
        if ((hadc->Instance->ISR & tmp_Flag_End) == 0UL)
        {
          /* Update ADC state machine to timeout */
          SET_BIT(hadc->State, HAL_ADC_STATE_TIMEOUT);

          /* Process unlocked */
          __HAL_UNLOCK(hadc);

          return HAL_TIMEOUT;
        }
      }
    }
  }