ADC and DMA Discovery Board F412 - cant get it to work

[SSchu.4]

Hi all,

I have two pins where I want to read in the voltage with ADC: PA5 and PA7.

Reading in each at its own with polling works fine.

Now I want to read them in both and continously. I understand that the right way to

go is DMA, contonious mode and scan mode.

I have set up a DMA Request:

circular; halfword/halfword; increment at memory

ADC Setup:

static void MX_ADC1_Init(void)
{
 
  /* USER CODE BEGIN ADC1_Init 0 */
  /* USER CODE END ADC1_Init 0 */
 
  ADC_ChannelConfTypeDef sConfig = {0};
 
  /* USER CODE BEGIN ADC1_Init 1 */
  /* USER CODE END ADC1_Init 1 */
  /** Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)
  */
  hadc1.Instance = ADC1;
  hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4;
  hadc1.Init.Resolution = ADC_RESOLUTION_12B;
  hadc1.Init.ScanConvMode = ENABLE;
  hadc1.Init.ContinuousConvMode = ENABLE;
  hadc1.Init.DiscontinuousConvMode = DISABLE;
  hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
  hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.NbrOfConversion = 2;
  hadc1.Init.DMAContinuousRequests = DISABLE;
  hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  if (HAL_ADC_Init(&hadc1) != HAL_OK)
  {
    Error_Handler();
  }
  /** Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time.
  */
  sConfig.Channel = ADC_CHANNEL_5;
  sConfig.Rank = 1;
  sConfig.SamplingTime = ADC_SAMPLETIME_15CYCLES;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /** Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time.
  */
  sConfig.Channel = ADC_CHANNEL_7;
  sConfig.Rank = 2;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN ADC1_Init 2 */
  /* USER CODE END ADC1_Init 2 */
 
}

Calling the function like that

// variable global
/* USER CODE BEGIN PV */
uint16_t adc_val[2];
/* USER CODE END PV */

 /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_ADC1_Init();
  MX_DMA_Init();
  /* USER CODE BEGIN 2 */
  /* USER CODE END 2 */
 
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
	  HAL_Delay(1000);
    /* USER CODE END WHILE */
 
    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */

Callback implemented

/* USER CODE BEGIN 4 */
HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* hadc){
	__NOP();
}
 
/* USER CODE END 4 */

Now the problem:

• Callback gets only called once
• Only one value is written to the DMA destination

Debug values are attached as screenshot.

Things I tried:

• Reordering init-functions (apperantly there is a bug, but this changed nothing)
• bigger buffers in DMA
• Setting ADC ECO Flag to "end of all conversion"
• DMA continuous requests to true

Nothing helped. I am kind of stuck. Any help appreciated.

[Tesla DeLorean]

Need to look at the DMA1 registers, confirm it's in circular mode, and not flagging errors

[TDK]

OVR bit is set in ADC_SR. An overrun will stop the ADC.

Slow down the conversions by increasing sampling time to max or by triggering off of a timer at a reasonable rate.

[MM..1]

Your code have three errors

1. DMA init order need before ADC
2. DMA continuous request need enable
3. ADC need call start i dont see this in your code.

And use one sample buffer with DMA isnt very effective