Setting up ADC in scan mode - callbacks not working

[NRumm.1]

Hi,

I'm having some hard time setting up my STM32F303RE Nucleo board for using the ADC.

What I want to achieve is...

• scanning 10 sensors (each connected to a GPIO pin on ADC2) in sequence three times
• transferring the data using DMA to a buffer
• getting called once conversion is done

I'm partially successful in getting the buffer filled with 10 samples, but neither does it provide all 30 samples, nor does it call the function HAL_ADC_ConvCpltCallback. Furthermore I've successfully used a timer for triggering the conversion in continuous mode, but never in single scan mode.

What I did so far using STM32CubeIDE was...

• set up the pins and the ADC2 channels
• configured DMA channel 2 for peripheral-to-memory transfer in circular mode
• set up ADC2 as outlined in the following initialization code

static void MX_ADC2_Init(void)
{
  /* USER CODE BEGIN ADC2_Init 0 */
  /* USER CODE END ADC2_Init 0 */
 
  ADC_ChannelConfTypeDef sConfig = {0};
 
  /* USER CODE BEGIN ADC2_Init 1 */
  /* USER CODE END ADC2_Init 1 */
  /** Common config
  */
  hadc2.Instance = ADC2;
  hadc2.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;
  hadc2.Init.Resolution = ADC_RESOLUTION_12B;
  hadc2.Init.ScanConvMode = ADC_SCAN_ENABLE;
  hadc2.Init.ContinuousConvMode = DISABLE;
  hadc2.Init.DiscontinuousConvMode = DISABLE;
  hadc2.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
  hadc2.Init.ExternalTrigConv = ADC_SOFTWARE_START;
  hadc2.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc2.Init.NbrOfConversion = 10;
  hadc2.Init.DMAContinuousRequests = ENABLE;
  hadc2.Init.EOCSelection = ADC_EOC_SEQ_CONV;
  hadc2.Init.LowPowerAutoWait = DISABLE;
  hadc2.Init.Overrun = ADC_OVR_DATA_OVERWRITTEN;
  if (HAL_ADC_Init(&hadc2) != HAL_OK)
  {
    Error_Handler();
  }
  /** Configure Regular Channel
  */
  sConfig.Channel = ADC_CHANNEL_2;
  sConfig.Rank = ADC_REGULAR_RANK_2;
  sConfig.SingleDiff = ADC_SINGLE_ENDED;
  sConfig.SamplingTime = ADC_SAMPLETIME_19CYCLES_5;
  sConfig.OffsetNumber = ADC_OFFSET_NONE;
  sConfig.Offset = 0;
  if (HAL_ADC_ConfigChannel(&hadc2, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /** Configure Regular Channel
  */
  sConfig.Channel = ADC_CHANNEL_3;
  sConfig.Rank = ADC_REGULAR_RANK_3;
  if (HAL_ADC_ConfigChannel(&hadc2, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
 // same for the other channels
}
 
/**
  * Enable DMA controller clock
  */
static void MX_DMA_Init(void)
{
  /* DMA controller clock enable */
  __HAL_RCC_DMA2_CLK_ENABLE();
 
  /* DMA interrupt init */
  /* DMA2_Channel1_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA2_Channel1_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA2_Channel1_IRQn);
}