I have an ADC with two channels on a nucleo f401re, one who reads values from a termistor(channel 8, rank1) and one who starts to read values from a potentiometer(channel 1, rank 2).Pressing the button on microcontroler should switch between the channels but I can only switch from channel 8 to 1.

I tried to switch their ranks or give them the same rank but it does’n work.

void change_channel(uint32_t channel, uint32_t  rank)
{    ADC_ChannelConfTypeDef sConfig = {0};
    sConfig.Channel = channel;
         sConfig.Rank = rank;
         if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
           {
             Error_Handler();
           }
         global_channel=sConfig.Channel;
         global_rank= sConfig.Rank;
}

I also tried to disable the other channel but it still doesn’t work.(it will read values only from the potentiometer).When i try to give sConfig.Rank = 2 when i disable the channels i read a value around 1310 for the termistor and i don’t know where it comes from.

void change_channel(uint32_t channel, uint32_t rank)
{
    ADC_ChannelConfTypeDef sConfig = {0};

    // Disable all channels
    for (uint32_t ch = ADC_CHANNEL_0; ch <= ADC_CHANNEL_10; ch++) // Adjust range based on your MCU's ADC channels
    {
        sConfig.Channel = ch;
        sConfig.Rank = 0; // Set rank to 0 to disable the channel (no valid rank)

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

    // Enable the desired channel
    sConfig.Channel = channel;
    sConfig.Rank = rank; // Explicitly set the desired rank
    if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
    {
        Error_Handler();
    }

    // Store the global variables for tracking
    global_channel = sConfig.Channel;
    global_rank = sConfig.Rank;
}

I read the values in the second task(mod is a variable that changes between 0 and 1 when i press the button to help me select the channel, 0 means automatic mode and 1 means manual mode)text

void StartTask02(void *argument)
{
  /* USER CODE BEGIN StartTask02 */
    float readValue;
    float voltage;
    float d=3.3;
    int mod1;


  /* Infinite loop */
  for(;;)
  {osMessageQueueGet (mod_for_ADCHandle, &mod1, 0, 0);
  if(mod1==0)//
  {
      change_channel(8,1);

     HAL_ADC_Start(&hadc1);
      if(HAL_ADC_PollForConversion(&hadc1,1000)==HAL_OK){
          readValue=HAL_ADC_GetValue(&hadc1);
        voltage=(float)readValue/(float)4095*d;
        globalvoltage= voltage;
        globalreadValue=readValue;
        }
              HAL_ADC_Stop(&hadc1);
            osMessageQueuePut (queque_voltageHandle, &voltage, 0, 0);
          osDelay(100);
  }

  if(mod1==1)//
  {
      change_channel(1,2);

     HAL_ADC_Start(&hadc1);
      if(HAL_ADC_PollForConversion(&hadc1,1000)==HAL_OK){
          readValue=HAL_ADC_GetValue(&hadc1);
        voltage=(float)readValue/(float)4095*d;
        globalvoltage= voltage;
        globalreadValue=readValue;
        }
              HAL_ADC_Stop(&hadc1);
            osMessageQueuePut (queque_voltageHandle, &voltage, 0, 0);
          osDelay(100);
  }
  }
  /* USER CODE END StartTask02 */
}

ADC configuration

  /** Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)
  */
  hadc1.Instance = ADC1;
  hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4;
  hadc1.Init.Resolution = ADC_RESOLUTION_12B;
  hadc1.Init.ScanConvMode = ENABLE;
  hadc1.Init.ContinuousConvMode = DISABLE;
  hadc1.Init.DiscontinuousConvMode = DISABLE;
  hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
  hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.NbrOfConversion = 2;
  hadc1.Init.DMAContinuousRequests = DISABLE;
  hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  if (HAL_ADC_Init(&hadc1) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time.
  */
  sConfig.Channel = ADC_CHANNEL_8;
  sConfig.Rank = 1;
  sConfig.SamplingTime = ADC_SAMPLETIME_480CYCLES;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time.
  */
  sConfig.Rank = 2;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }