本人接触stm32f 时间不长，在一个项目上使用了stm32f302rc这个芯片，初始化代码用的是STM32CubeMX生成的。ADC1、ADC2各有4路模拟输入。目前遇到的问题是ADC1采样正常，但ADC2采样不正常，输入0V时ADC2始终不为零，
大概有0.9V左右（3.3V基准）。这个问题已经困扰了几天了，还没有解决。求各位高人帮忙看看，如何解决。

谢谢！！
以下是初始化代码：
ADC_HandleTypeDef hadc1;
ADC_HandleTypeDef hadc2;
DMA_HandleTypeDef hdma_adc1;
DMA_HandleTypeDef hdma_adc2;

/* ADC1 init function */
void MX_ADC1_Init(void)
{
  ADC_ChannelConfTypeDef sConfig;
       
        /**Common config */
  hadc1.Instance = ADC1;
  hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV1;
  hadc1.Init.Resolution = ADC_RESOLUTION_12B;
  hadc1.Init.ScanConvMode = ADC_SCAN_ENABLE;
  hadc1.Init.ContinuousConvMode = DISABLE;
  hadc1.Init.DiscontinuousConvMode = DISABLE;
  hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_RISING;
  hadc1.Init.ExternalTrigConv = ADC_EXTERNALTRIGCONV_T4_TRGO;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.NbrOfConversion = 4;
  hadc1.Init.DMAContinuousRequests =DISABLE;
  hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  hadc1.Init.LowPowerAutoWait = DISABLE;
  hadc1.Init.Overrun = ADC_OVR_DATA_OVERWRITTEN;
  if (HAL_ADC_Init(&hadc1) != HAL_OK)
  {
    Error_Handler();
  }
       
        /**Configure Regular Channel */

  sConfig.SingleDiff = ADC_SINGLE_ENDED;
  sConfig.SamplingTime = ADC_SAMPLETIME_19CYCLES_5;
  sConfig.OffsetNumber = ADC_OFFSET_NONE;
  sConfig.Offset = 0;

        sConfig.Channel = ADC_CHANNEL_1;
  sConfig.Rank = 1;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
                /**Configure Regular Channel*/
  sConfig.Channel = ADC_CHANNEL_2;
  sConfig.Rank = 2;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
                /**Configure Regular Channel*/
  sConfig.Channel = ADC_CHANNEL_3;
  sConfig.Rank = 3;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
                /**Configure Regular Channel*/
  sConfig.Channel = ADC_CHANNEL_4;
  sConfig.Rank = 4;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
       
                HAL_ADCEx_Calibration_Start(&hadc1, ADC_SINGLE_ENDED);
               
                HAL_ADC_Start_DMA(&hadc1, (U32*)ADC1_ConvertedValue,ADC_SampleCount);

}

/* ADC2 init function */
void MX_ADC2_Init(void)
{
  ADC_ChannelConfTypeDef sConfig;
       
        /**Common config */
  hadc2.Instance = ADC2;
  hadc2.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV1;
  hadc2.Init.Resolution = ADC_RESOLUTION_12B;
  hadc2.Init.ScanConvMode = ADC_SCAN_ENABLE;
  hadc2.Init.ContinuousConvMode = DISABLE;
  hadc2.Init.DiscontinuousConvMode = DISABLE;
  hadc2.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_RISING;
  hadc2.Init.ExternalTrigConv = ADC_EXTERNALTRIGCONV_T4_TRGO;
  hadc2.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc2.Init.NbrOfConversion = 4;
  hadc2.Init.DMAContinuousRequests = DISABLE;
  hadc2.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  hadc2.Init.LowPowerAutoWait = DISABLE;
  hadc2.Init.Overrun = ADC_OVR_DATA_OVERWRITTEN;
  if (HAL_ADC_Init(&hadc2) != HAL_OK)
  {
    Error_Handler();
  }

        /**Configure Regular Channel*/

  sConfig.SingleDiff = ADC_SINGLE_ENDED;
  sConfig.SamplingTime = ADC_SAMPLETIME_19CYCLES_5;
  sConfig.OffsetNumber = ADC_OFFSET_NONE;
  sConfig.Offset = 0;
       
        sConfig.Channel = ADC_CHANNEL_6;
  sConfig.Rank = 1;
  if (HAL_ADC_ConfigChannel(&hadc2, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
       
  /**Configure Regular Channel */
  sConfig.Channel = ADC_CHANNEL_7;
  sConfig.Rank = 2;
  if (HAL_ADC_ConfigChannel(&hadc2, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
    /**Configure Regular Channel*/
  sConfig.Channel = ADC_CHANNEL_8;
  sConfig.Rank = 3;
  if (HAL_ADC_ConfigChannel(&hadc2, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
    /**Configure Regular Channel*/

  sConfig.Channel = ADC_CHANNEL_9;
  sConfig.Rank = 4;
  if (HAL_ADC_ConfigChannel(&hadc2, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
       
        HAL_ADCEx_Calibration_Start(&hadc2, ADC_SINGLE_ENDED);
       
        HAL_ADC_Start_DMA(&hadc2, (U32*)ADC2_ConvertedValue, ADC_SampleCount);
}

static uint32_t HAL_RCC_ADC12_CLK_ENABLED=0;

void HAL_ADC_MspInit(ADC_HandleTypeDef* adcHandle)
{

  GPIO_InitTypeDef GPIO_InitStruct;
  if(adcHandle->Instance==ADC1)
  {
    /* Peripheral clock enable */
    HAL_RCC_ADC12_CLK_ENABLED++;
    if(HAL_RCC_ADC12_CLK_ENABLED==1){
      __HAL_RCC_ADC12_CLK_ENABLE();
    }

    /**ADC1 GPIO Configuration   
    PA0     ------> ADC1_IN1
    PA1     ------> ADC1_IN2
    PA2     ------> ADC1_IN3
    PA3     ------> ADC1_IN4
    */
    GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3;
    GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

    /* Peripheral DMA init*/

    hdma_adc1.Instance = DMA1_Channel1;
    hdma_adc1.Init.Direction = DMA_PERIPH_TO_MEMORY;
    hdma_adc1.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_adc1.Init.MemInc = DMA_MINC_ENABLE;
    hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
    hdma_adc1.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
    hdma_adc1.Init.Mode = DMA_CIRCULAR;//DMA_NORMAL;
    hdma_adc1.Init.Priority = DMA_PRIORITY_MEDIUM;
    if (HAL_DMA_Init(&hdma_adc1) != HAL_OK)
    {
      Error_Handler();
    }

    __HAL_LINKDMA(adcHandle,DMA_Handle,hdma_adc1);

    /* Peripheral interrupt init */
    //HAL_NVIC_SetPriority(ADC1_2_IRQn, 0, 0);
    //HAL_NVIC_EnableIRQ(ADC1_2_IRQn);
  }
  else if(adcHandle->Instance==ADC2)
  {
    /* Peripheral clock enable */
    HAL_RCC_ADC12_CLK_ENABLED++;
    if(HAL_RCC_ADC12_CLK_ENABLED==1){
      __HAL_RCC_ADC12_CLK_ENABLE();
    }

    /**ADC2 GPIO Configuration   
    PC0     ------> ADC2_IN6
    PC1     ------> ADC2_IN7
    PC2     ------> ADC2_IN8
    PC3     ------> ADC2_IN9
    */
    GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3;
    GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
               
    /* Peripheral DMA init*/

    hdma_adc2.Instance = DMA2_Channel1;
    hdma_adc2.Init.Direction = DMA_PERIPH_TO_MEMORY;
    hdma_adc2.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_adc2.Init.MemInc = DMA_MINC_ENABLE;
    hdma_adc2.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
    hdma_adc2.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
    hdma_adc2.Init.Mode = DMA_CIRCULAR;//DMA_NORMAL;
    hdma_adc2.Init.Priority = DMA_PRIORITY_MEDIUM;
    if (HAL_DMA_Init(&hdma_adc2) != HAL_OK)
    {
      Error_Handler();
    }

    __HAL_LINKDMA(adcHandle,DMA_Handle,hdma_adc2);

    /* Peripheral interrupt init */
    //HAL_NVIC_SetPriority(ADC1_2_IRQn, 0, 0);
    //HAL_NVIC_EnableIRQ(ADC1_2_IRQn);
  }
}