STM32F070 ADC single channel issue

[VDutt.1]

Hi,

Recently I started working on stm32F07 microcontroller. I am trying to read sensor value using ADC.

Issue: ADC value is keep on changing randomly(means its not holding value).

Below is my code. Please refer it and help me to figure out the issue.

Clock is 48Mhz.

Handler:

void HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* hadc)

{

 if (__HAL_ADC_GET_FLAG(hadc, ADC_FLAG_EOC))

  {

 adcval = HAL_ADC_GetValue(hadc);

 volt = 3300 * (*VREFINT_CAL_ADDR)/adcval;

// Pressure=volt*adcval/4095;

  }

}

main function:

 MX_GPIO_Init();

 MX_ADC_Init();

 /* USER CODE BEGIN 2 */

 HAL_ADC_Start_IT(&hadc);

 /* USER CODE END 2 */

 /* Infinite loop */

 /* USER CODE BEGIN WHILE */

 while (1)

 {

  /* USER CODE END WHILE */

  /* USER CODE BEGIN 3 */

 HAL_Delay(200);

 HAL_ADC_Start_IT(&hadc);

 }

ADC Configuration:

static void MX_ADC_Init(void)

{

 /* USER CODE BEGIN ADC_Init 0 */

 /* USER CODE END ADC_Init 0 */

 ADC_ChannelConfTypeDef sConfig = {0};

 /* USER CODE BEGIN ADC_Init 1 */

 /* USER CODE END ADC_Init 1 */

 /** Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)

 */

 hadc.Instance = ADC1;

 hadc.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;

 hadc.Init.Resolution = ADC_RESOLUTION_12B;

 hadc.Init.DataAlign = ADC_DATAALIGN_RIGHT;

 hadc.Init.ScanConvMode = ADC_SCAN_DIRECTION_FORWARD;

 hadc.Init.EOCSelection = ADC_EOC_SINGLE_CONV;

 hadc.Init.LowPowerAutoWait = DISABLE;

 hadc.Init.LowPowerAutoPowerOff = DISABLE;

 hadc.Init.ContinuousConvMode = DISABLE;

 hadc.Init.DiscontinuousConvMode = DISABLE;

 hadc.Init.ExternalTrigConv = ADC_SOFTWARE_START;

 hadc.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;

 hadc.Init.DMAContinuousRequests = DISABLE;

 hadc.Init.Overrun = ADC_OVR_DATA_PRESERVED;

 if (HAL_ADC_Init(&hadc) != HAL_OK)

 {

  Error_Handler();

 }

 /** Configure for the selected ADC regular channel to be converted.

 */

 sConfig.Channel = ADC_CHANNEL_0;

 sConfig.Rank = ADC_RANK_CHANNEL_NUMBER;

 sConfig.SamplingTime = ADC_SAMPLETIME_239CYCLES_5;

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

 {

  Error_Handler();

 }

 /** Configure for the selected ADC regular channel to be converted.

 */

 sConfig.Channel = ADC_CHANNEL_VREFINT;

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

 {

  Error_Handler();

 }

 /* USER CODE BEGIN ADC_Init 2 */

 /* USER CODE END ADC_Init 2 */

}

IOC File:

 Thanks & regards.

Vivek

[ChahinezC]

Hello @VDutt.1​,

First, please add the ADC calibration function to improve the conversion accuracy: HAL_ADCEx_Calibration_Start.

Another point is that I recommend you verifying the formula you are using to calculate the converted value.

Referring to the RM0360; the “Converting a supply-relative ADC measurement to an absolute voltage value�? part of the 12.9 section, if you have a known VDDA use the first formula, if not, refer to the VREFINT.

Chahinez.

[Flyback]

I believe I have the same issue.

I do calibration after reset, in the end of the ADC_Init.

Have you found a solution? Thanks!

[Karl Yamashita]

Use the </> when posting code so it's formatted and readable.