ADC scan continuous mode with DMA in STM32H7 - all values are 0.

[Mdi c]

Dear all,

I am trying to read 3 ADCs channels using scan continuous mode and DMA with a STM32H7 (ADC3). Below the CubeMx settings + DMA.

In the main, before the While(1) loop I start the ADC with:

HAL_ADC_Start_DMA(&hadc3, (uint32_t*)adc_data, 3) ;

Where ADC_Values is uint32_t adc_data[3];

When I run the debugger, adc_data is always 0x0000.

Any hint?

Thanks

[Yoichi Shinoda]

Are you handling the buffer coherency issue for ADC DMA read buffer correctly?

https://community.st.com/s/article/FAQ-DMA-is-not-working-on-STM32H7-devices

[Mdi c]

Hello @Yoichi Shinoda​ , thank you for your answer. I came accross that article and I think that's the issue I have. I tried to follow it but I think my knowledge about STM32 MCUs is too limited to really understand it ..

[Imen GH]

​

Hello,

You should change the memory address, as shown in Figure (when using IAR)

 Please find attached the RM0433 Rev 6  (page 101, 128) link for more clarification

Regards

[Nesrine.JLASSI]

Hi all,

User have to do this update

define symbol __ICFEDIT_region_RAM_start__ = 0x24000000;

define symbol __ICFEDIT_region_RAM_end__ = 0x2407FFFF;

manually (in the stm32h743xx_flash.icf ) since linker file is not managed by STM32CubeMX (copied from the FW package).

Best regards,

Nesrine

[Mdi c]

Dear @Nesrine.JLASSI​ , is this equivalent to setting the IRAM2 region in the target option in Keil ?

[Mdi c]

Hello @Nesrine.JLASSI​  and @Imen GH​ , modifying the IRAM2 in Keil did the trick. Now I can see the data being acquired by the MCU. However, I noticed that despite the ADC resolution is set to 16bits, I can only read 8bits since the the 8 LSBs are always 0, as shown in the debugger view below:

where :

uint16_t adc_data[7];

HAL_ADC_Start_DMA(&hadc1, (uint32_t*)adc_data, 7) ;

ADC initialization code:

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_16B;

 hadc1.Init.ScanConvMode = ADC_SCAN_ENABLE;

 hadc1.Init.EOCSelection = ADC_EOC_SEQ_CONV;

 hadc1.Init.LowPowerAutoWait = DISABLE;

 hadc1.Init.ContinuousConvMode = ENABLE;

 hadc1.Init.NbrOfConversion = 7;

 hadc1.Init.DiscontinuousConvMode = DISABLE;

 hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;

 hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;

 hadc1.Init.ConversionDataManagement = ADC_CONVERSIONDATA_DMA_CIRCULAR;

 hadc1.Init.Overrun = ADC_OVR_DATA_PRESERVED;

 hadc1.Init.LeftBitShift = ADC_LEFTBITSHIFT_NONE;

 hadc1.Init.OversamplingMode = ENABLE;

 hadc1.Init.Oversampling.Ratio = 8;

 hadc1.Init.Oversampling.RightBitShift = ADC_RIGHTBITSHIFT_3;

 hadc1.Init.Oversampling.TriggeredMode = ADC_TRIGGEREDMODE_SINGLE_TRIGGER;

 hadc1.Init.Oversampling.OversamplingStopReset = ADC_REGOVERSAMPLING_CONTINUED_MODE;

 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_3;

 sConfig.Rank = ADC_REGULAR_RANK_1;

 sConfig.SamplingTime = ADC_SAMPLETIME_387CYCLES_5;

 sConfig.SingleDiff = ADC_SINGLE_ENDED;

 sConfig.OffsetNumber = ADC_OFFSET_NONE;

 sConfig.Offset = 0;

 if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

 {

  Error_Handler();

 }

 /** Configure Regular Channel 

 */

 sConfig.Channel = ADC_CHANNEL_4;

 sConfig.Rank = ADC_REGULAR_RANK_2;

 if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

 {

  Error_Handler();

 }

 /** Configure Regular Channel 

 */

 sConfig.Channel = ADC_CHANNEL_5;

 sConfig.Rank = ADC_REGULAR_RANK_3;

 if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

 {

  Error_Handler();

 }

 /** Configure Regular Channel 

 */

 sConfig.Channel = ADC_CHANNEL_9;

 sConfig.Rank = ADC_REGULAR_RANK_4;

 if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

 {

  Error_Handler();

 }

 /** Configure Regular Channel 

 */

 sConfig.Channel = ADC_CHANNEL_14;

 sConfig.Rank = ADC_REGULAR_RANK_5;

 if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

 {

  Error_Handler();

 }

 /** Configure Regular Channel 

 */

 sConfig.Channel = ADC_CHANNEL_15;

 sConfig.Rank = ADC_REGULAR_RANK_6;

 if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

 {

  Error_Handler();

 }

 /** Configure Regular Channel 

 */

 sConfig.Channel = ADC_CHANNEL_19;

 sConfig.Rank = ADC_REGULAR_RANK_7;

 if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

 {

  Error_Handler();

 }

 /* USER CODE BEGIN ADC1_Init 2 */

 /* USER CODE END ADC1_Init 2 */

}