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NUCLEO-G431KB, wrong values on ADC channel 4

Heinrich
Associate III

Hello Forum,

I have an issue while reading the values from ADC. ADC1 is running in "continues scan convertion mode" using DMA and 5 ranks.

Here is ADC_Init function:

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_SYNC_PCLK_DIV4;
  hadc1.Init.Resolution = ADC_RESOLUTION_12B;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.GainCompensation = 0;
  hadc1.Init.ScanConvMode = ADC_SCAN_ENABLE;
  hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  hadc1.Init.LowPowerAutoWait = DISABLE;
  hadc1.Init.ContinuousConvMode = ENABLE;
  hadc1.Init.NbrOfConversion = 5;
  hadc1.Init.DiscontinuousConvMode = DISABLE;
  hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
  hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
  hadc1.Init.DMAContinuousRequests = ENABLE;
  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_TEMPSENSOR_ADC1;
  sConfig.Rank = ADC_REGULAR_RANK_1;
  sConfig.SamplingTime = ADC_SAMPLETIME_247CYCLES_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_VREFINT;
  sConfig.Rank = ADC_REGULAR_RANK_2;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure Regular Channel
  */
  sConfig.Channel = ADC_CHANNEL_1;
  sConfig.Rank = ADC_REGULAR_RANK_3;
  sConfig.SamplingTime = ADC_SAMPLETIME_24CYCLES_5;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure Regular Channel
  */
  sConfig.Channel = ADC_CHANNEL_2;
  sConfig.Rank = ADC_REGULAR_RANK_4;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure Regular Channel
  */
  sConfig.Channel = ADC_CHANNEL_4;
  sConfig.Rank = ADC_REGULAR_RANK_5;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN ADC1_Init 2 */

  /* USER CODE END ADC1_Init 2 */

}

Then, here is my main() function:

int main(void)
{

  /* USER CODE BEGIN 1 */


  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_DMA_Init();
  MX_DAC1_Init();
  MX_I2C2_Init();
  MX_USB_Device_Init();
  MX_TIM17_Init();
  MX_CRC_Init();
  MX_ADC1_Init();
  /* USER CODE BEGIN 2 */
  if (HAL_ADCEx_Calibration_Start(&hadc1, ADC_SINGLE_ENDED) != HAL_OK)
  {
	  Error_Handler();
  }

  if (HAL_ADC_Start_DMA(&hadc1, (uint32_t *) &adc_convertions, 5) != HAL_OK)
  {
	  Error_Handler();
  }



  HAL_DAC_Start(&hdac1, DAC1_CHANNEL_1);
  HAL_DAC_Start(&hdac1, DAC1_CHANNEL_2);
  HAL_TIM_Base_Start_IT(&htim17);

  AT24CXX_Init(hi2c2);
  load_configuration();
  init_spline();
  // load_default_configuration();

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
	  timer_tasks_execute();

	  if (received_data)
	  {
		  process_tunerstudio();
		  received_data = false;
	  }
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

The variable adc_convertions is declared as uint32_t adc_convertions[5] = {0};

Issue:

If I apply the a voltage (2.15v) to PA1 and PA3, in adc_convertions array I get the ADC of 2620 for PA1 and 1531 for PA3. But, the both values shold be equal... The another ranks in adc_convertions array are correct.

  • I've tried to change a sample time for CHANNEL4 (= PA3), no success.
  • I removed SB1 and SB12 (because PA3 is connected to STLINK-V3E virtual c omport) , no success.
  • I've tried to map CHANNEL4 to different Rank, no success.

So, 'Ive no idea anymore...

Can you please help me?

Many thanks & regards,
Heinrich

1 ACCEPTED SOLUTION

Accepted Solutions
waclawek.jan
Super User

> If I apply the a voltage (2.15v) to PA1 and PA3

So, are PA1 and PA3 physically connected together?

> I removed SB1 and SB12 (because PA3 is connected to STLINK-V3E virtual c omport)

And did you connect SB14?

JW

View solution in original post

11 REPLIES 11
Karl Yamashita
Principal

Change your type to uint16_t instead of uint32_t 

 

I was told that if a devices starts to smoke, put the smoke back in. I guess I never got all the smoke because the device never worked afterwards.
Don't worry, I won't byte.
TimerCallback tutorial! | UART and DMA Idle with multiple UART instances tutorial!

If you find my solution useful, please click the Accept as Solution so others see the solution.

Do you mean the type of adc_convertions[5]?

Regards,
Heinrich

MasterT
Lead

Instead:

if (HAL_ADC_Start_DMA(&hadc1, (uint32_t *) &adc_convertions, 5) != HAL_OK)

try:

if (HAL_ADC_Start_DMA(&hadc1, (uint32_t *)  adc_convertions, 5) != HAL_OK)

 

And declaration of : uint32_t adc_convertions[5] = {0}; depends on DMA_word size, what we can't see, since no dma config provided.

waclawek.jan
Super User

> If I apply the a voltage (2.15v) to PA1 and PA3

So, are PA1 and PA3 physically connected together?

> I removed SB1 and SB12 (because PA3 is connected to STLINK-V3E virtual c omport)

And did you connect SB14?

JW

Yes ADC is 12bit then optimal result is 16bit half word DMA and uint16_t array.

And for addressing array right syntax is adc_convertions or &adc_convertions[0] .

Heinrich
Associate III

Hi guys, first of all, thank you very much for help :)

@MasterT:

DMA is configured like this at the moment:

Heinrich_0-1728739610358.png

Since STM32 is a 32-bit MCU, WORD means uint32_t, I think... It is correct?

@waclawek.jan 

Yes, PA1 and PA3 are connected together. Not directly on Nucleo, but on carrier board. The is a voltage divider (5v to 3.3), then buffer and then NUCLEO. AI've applied 3.3v from NUCLEO to both input pins, after voltage diviers and buffers, I get 2.15v on BOTH pins of NUCLEO. So, the hardware should be okay, because the get the same voltage.

No, SB15 is still default, so not "installed".

@MM..1Okay, I've removed & , the DMA is configured as word, not half-word.

What I've done:

  • Remove the & in if (HAL_ADC_Start_DMA(&hadc1, (uint32_t *) adc_convertions, 5) != HAL_OK)
  • Changed uint32_t to uint16_t.

Result:

  • CHANNEL1 (adc_convertions[0]) says 2620, correct.
  • CHANNEL4 (adc_convertions[1]) says 0, normal since SB14 is open...

I will close SB14 a bit later and test it :)

If DMA configured as Word_Peripheral- Word_Memory, than 

uint32_t adc_convertions[5] = {0};  or int32_t adc_convertions[5] = {0};

correct declaration. 

For Halfword_Peripheral- Halfword_Memory, than 

uint16_t adc_convertions[5] = {0};  or int16_t adc_convertions[5] = {0}; 

Okay, then it was correct.

I've changed them back to uint32_t adc_convertions[5] = {0};

and:

  • adc_convertions[0] says 2621, correct
  • adc_convertions[1] says 1543, wrong

I'll test with SB14 closed today evening.

Regards,
Heinrich

sConfig.Channel = ADC_CHANNEL_VREFINT;
  sConfig.Rank = ADC_REGULAR_RANK_2;

why you mean this must equal RANK_1 ? And for effectivity set DMA to half word and array to uint16 ...