ADC using DMA works in 8-bit mode even though a resolution of 12-bit is activated.

[fiona_io]

Hello,

I would like to use an ADC using DMA in 12-bit mode. 

Unfortuntaly, the adc value is only 8-bit which doesn't match with my configuration. I've already tried to solve the problem by trying the solution proposed here: https://community.st.com/t5/stm32-mcus-products/why-would-an-adc-sample-in-8-bit-mode-when-dma-is-used-but-when/m-p/197276/highlight/true#M42484

But it didn't work in my case.

Here's my source code for dma and adc. I am not working with the cubeIDE anymore, that's why my configuration functions look different than the auto-generated init-functions of the IDE. The weird thing is that the same configuration is working in the CubeIDE... (so maybe it's a structual problem in my configuration)

ADC_HandleTypeDef hadc1;
DMA_HandleTypeDef hdma_adc1;

uint16_t buffer;
uint16_t adc_value;

 void DMA1_Channel1_IRQHandler(void) {
   HAL_DMA_IRQHandler(&hdma_adc1);
 }

void HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* hadc) {
   adc_value = buffer; //store value
}

void adcInit(void) {
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
  ADC_MultiModeTypeDef multimode = {0};
  ADC_ChannelConfTypeDef sConfig = {0};
  __HAL_RCC_ADC12_CLK_ENABLE();
  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_ADC12;
  PeriphClkInit.Adc12ClockSelection = RCC_ADC12CLKSOURCE_SYSCLK;

  if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK) {
    Error_Handler();
  }

  __HAL_RCC_GPIOC_CLK_ENABLE();

  /**ADC1 GPIO Configuration
  PC2     ------> ADC1_IN8
  */

  GPIO_InitStruct.Pin = GPIO_PIN_2;
  GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  hadc1.Instance = ADC1;
  hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV2;
  hadc1.Init.Resolution = ADC_RESOLUTION_12B;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.GainCompensation = 0;
  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.DMAContinuousRequests = DISABLE;
  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_8;
  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;

  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK) {
    Error_Handler();
  }
}

void dmaInit() {

    /* DMA controller clock enable */
    __HAL_RCC_DMAMUX1_CLK_ENABLE();
    __HAL_RCC_DMA1_CLK_ENABLE();

    /* DMA interrupt init */
    /* DMA1_Channel1_IRQn interrupt configuration */
    HAL_NVIC_SetPriority(DMA1_Channel1_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(DMA1_Channel1_IRQn);
    //HAL_DMA_IRQHandler(&hdma_adc1);

    /* ADC1 Init */
    hdma_adc1.Instance = DMA1_Channel1;
    hdma_adc1.Init.Request = DMA_REQUEST_ADC1;
    hdma_adc1.Init.Direction = DMA_PERIPH_TO_MEMORY;
    hdma_adc1.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_adc1.Init.MemInc = DMA_MINC_ENABLE;
    hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
    hdma_adc1.Init.MemDataAlignment = DMA_PDATAALIGN_HALFWORD;
    hdma_adc1.Init.Mode = DMA_CIRCULAR;
    hdma_adc1.Init.Priority = DMA_PRIORITY_HIGH;
    if (HAL_DMA_Init(&hdma_adc1) != HAL_OK) {
      Error_Handler();
    }
    __HAL_LINKDMA(&hadc1,DMA_Handle,hdma_adc1);
}

void initProcess(void) {
    dmaInit();
    adcInit();
    HAL_ADC_Start_DMA(&hadc1, &buffer, 1);
}

[SofLit]

Dear @fiona_io ,

Please in next time use </> button instead of "Spoiler Tag" button to paste your code.