STM32 利用内部参考电压VREFINT计算VDDA来提高精度

/* ADC1 init function */
void MX_ADC1_Init(void)
{
  ADC_ChannelConfTypeDef sConfig = {0};
  
  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.ScanConvMode = ADC_SCAN_ENABLE;
  hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  hadc1.Init.LowPowerAutoWait = DISABLE;
  hadc1.Init.LowPowerAutoPowerOff = DISABLE;
  hadc1.Init.ContinuousConvMode = ENABLE;
  hadc1.Init.NbrOfConversion = 4;
  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.SamplingTimeCommon1 = ADC_SAMPLETIME_160CYCLES_5;
  hadc1.Init.SamplingTimeCommon2 = ADC_SAMPLETIME_160CYCLES_5;
  hadc1.Init.OversamplingMode = DISABLE;
  hadc1.Init.TriggerFrequencyMode = ADC_TRIGGER_FREQ_HIGH;
  if (HAL_ADC_Init(&hadc1) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure Regular Channel
  */
  sConfig.Channel = ADC_CHANNEL_0;
  sConfig.Rank = ADC_REGULAR_RANK_1;
  sConfig.SamplingTime = ADC_SAMPLINGTIME_COMMON_1;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure Regular Channel
  */
  sConfig.Channel = ADC_CHANNEL_1;
  sConfig.Rank = ADC_REGULAR_RANK_2;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure Regular Channel
  */
  sConfig.Channel = ADC_CHANNEL_2;
  sConfig.Rank = ADC_REGULAR_RANK_3;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure Regular Channel
  */
  sConfig.Channel = ADC_CHANNEL_VREFINT;
  sConfig.Rank = ADC_REGULAR_RANK_4;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
  
  /* USER CODE BEGIN ADC1_Init 2 */
  HAL_ADCEx_Calibration_Start(&hadc1);  // 必须加校准
  /* USER CODE END ADC1_Init 2 */

}

        //------ AVDD参考电压 ------
        filter_buf_AVDD[index_AVDD_flag++] = adcInfor.data[3];  
        index_AVDD_flag = index_AVDD_flag > (ADC_FILTER_N-1) ? 0 : index_AVDD_flag;
        if(index_AVDD_flag == (ADC_FILTER_N-1))
        {
          index_AVDD_full = 1;
        }
        if(index_AVDD_full == 1)
        {
            filter_Sum_AVDD = 0;
            for(uint16_t i=0;i<ADC_FILTER_N;i++)
            {
              filter_Sum_AVDD += filter_buf_AVDD[i];
            }
            
            AVDD_ADCtemp = filter_Sum_AVDD/ADC_FILTER_N;
            // 计算VDDA电压
            // 从芯片的特定位置读取VREFINT校准值(出厂校准值)
            uint16_t vrefint_cal = *((uint16_t *)VREFINT_CAL_ADDR);
        
            // VREFINT校准值是在VDDA=3.0V时测量的
            Vref_AVDD = (3.0f * (float)vrefint_cal)/(float)AVDD_ADCtemp;

这里的Vref_AVDD 就是ADC的参考电压！