Unstable ADC readings with STM32F030

[MAern.1]

Hello all

I have a problem with unstable ADC readings with my STM32F030

I use CubeMX to set up my device.

My ADC init :

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_10B;
  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_1;
  if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /** Configure for the selected ADC regular channel to be converted. 
  */
  sConfig.Channel = ADC_CHANNEL_3;
  if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN ADC_Init 2 */
  while(HAL_ADCEx_Calibration_Start(&hadc) != HAL_OK){};   // Calibration of ADC
  /* USER CODE END ADC_Init 2 */
 
}

and here the part in my Main:

(STATE_ADC_channel = ADC_CHANNEL_0)

config_ext_ADC_channel(STATE_ADC_channel,true);
                
                HAL_ADC_Start(&hadc);
LED_RED_ON;                
//                HEAT_CHARGE_OFF;	// FET_OFF                
                
                HAL_ADC_PollForConversion(&hadc, HAL_MAX_DELAY);
                
                adc_data = HAL_ADC_GetValue(&hadc);
LED_RED_OFF;               
                if(adc_data <= min_state)          // Master Pack oder Ladegerät gefunden
                {
                    
//                   HEAT_CHARGE_ON;	// FET_ON                
                    detect_pos_pulse++;                 // count heat pulse on
                }
                else
                {
                    detect_neg_pulse++;                 // count heat pulse off
                }
                
                config_ext_ADC_channel(STATE_ADC_channel,false);

i must read the ADC as fast as possible because of detecting some 500us pulses.

Now if i debug with the breakpoint in line :

if(adc_data <= min_state)

i get this on my scope :

UPDATE: better scope picture

Blue is LED_RED on off

Green is my signal to measure.

ADC result switches between 0 and 560 with the exact same scope screen.

Can someone please guide me in the right direction to solve this problem.

Thanks a lot

Markus

[TDK]

I'm not seeing a problem. Green signal goes from 0 to about midway, which is about 0 to 500 (with 10 bit ADC), in line with your readings.