ADC采集3.3V的电压时怎么显示只有2.2V

只看该作者 · 2017-1-13 12:54

用F103RCT6的板子采集3.3V电压，但是显示出来只有2.2V左右，是怎么回事

本人小白，求教各位大大

#define ADC1_DR_Address ((u32)0x4001244C)

__IO u32 ADC_ConvertedValue;

#define  N 50

u32  AD_Value[N];
u32  After_filter;

void ADC1_GPIO_Config(void)
{ GPIO_InitTypeDef GPIO_InitStructure;
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
}

void ADC1_Mode_Config(void)
{
  DMA_InitTypeDef DMA_InitStructure;
  ADC_InitTypeDef ADC_InitStructure;
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
/* DMA channel1 configuration */
  DMA_DeInit(DMA1_Channel1);
  DMA_InitStructure.DMA_PeripheralBaseAddr = ADC1_DR_Address;
  DMA_InitStructure.DMA_MemoryBaseAddr = (u32)&AD_Value;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
  DMA_InitStructure.DMA_BufferSize = N;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  DMA_Init(DMA1_Channel1, &DMA_InitStructure);

  /* Enable DMA channel1 */
  DMA_Cmd(DMA1_Channel1, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);

  /* ADC1 configuration */
  ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
  ADC_InitStructure.ADC_ScanConvMode = DISABLE;
  ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
  ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
  ADC_InitStructure.ADC_NbrOfChannel = 1;

  /* ADC1 regular channel11 configuration */
  ADC_RegularChannelConfig(ADC1, ADC_Channel_1, 1, ADC_SampleTime_55Cycles5);

  /* Enable ADC1 DMA */
  ADC_DMACmd(ADC1, ENABLE);

  /* Enable ADC1 */
  ADC_Cmd(ADC1, ENABLE);

  /* Enable ADC1 reset calibaration register */
  ADC_ResetCalibration(ADC1);
  /* Check the end of ADC1 reset calibration register */
  while(ADC_GetResetCalibrationStatus(ADC1));

  /* Start ADC1 calibaration */
  ADC_StartCalibration(ADC1);
  /* Check the end of ADC1 calibration */
  while(ADC_GetCalibrationStatus(ADC1));

  /* Start ADC1 Software Conversion */
  ADC_SoftwareStartConvCmd(ADC1, ENABLE);
}

void ADC1_Init(void)
{
ADC1_GPIO_Config();
ADC1_Mode_Config();
}

void filter(void)
{
      u32  sum = 0;

      u8  count;

      for ( count=0;count<N;count++)

      {
         sum += AD_Value[count];
      }

      After_filter=sum/N;

      sum=0;
   }