STM32F105 ADC采集数据时，IO电压一样，采集数据不一样是为什么？

如题，STM32F105，DMA方式采集ADC数据，其中两路，IO口电压一样，但采集数据不一样。数据相差较大，且差值不固定。

请大神指导。

void SysInit_ADC(void)
{
         ADC_InitTypeDef ADC_InitStructure;
         RCC_ADCCLKConfig(RCC_PCLK2_Div2);
/* Enable ADC1*/
           RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
         ADC_DeInit(ADC1);
/* Initialize the ADCx according to the ADC_InitStructure members */
         ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
         ADC_InitStructure.ADC_ScanConvMode = ENABLE;
         ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
         ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
         ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
         ADC_InitStructure.ADC_NbrOfChannel = 7;
         ADC_Init(ADC1, ADC_InitStructure);
         ADC_RegularChannelConfig(ADC1, ADC_Channel_0, 1, ADC_SampleTime_41Cycles5);
         ADC_RegularChannelConfig(ADC1, ADC_Channel_1, 2, ADC_SampleTime_41Cycles5);
         ADC_RegularChannelConfig(ADC1, ADC_Channel_2, 3, ADC_SampleTime_41Cycles5);
         ADC_RegularChannelConfig(ADC1, ADC_Channel_3, 4, ADC_SampleTime_41Cycles5);
         ADC_RegularChannelConfig(ADC1, ADC_Channel_4, 5, ADC_SampleTime_41Cycles5);
         ADC_RegularChannelConfig(ADC1, ADC_Channel_8, 6, ADC_SampleTime_41Cycles5);
         ADC_RegularChannelConfig(ADC1, ADC_Channel_5, 7, ADC_SampleTime_41Cycles5);
/* Enable ADC1 DMA */
           ADC_DMACmd(ADC1, ENABLE);
/* Enable ADC1 */
         ADC_Cmd(ADC1,ENABLE);
/* Enable ADC1 reset calibration register */   
           ADC_ResetCalibration(ADC1);
/* Check the end of ADC1 reset calibration register */
           while(ADC_GetResetCalibrationStatus(ADC1));
/* Start ADC1 calibration */
           ADC_StartCalibration(ADC1);
/* Check the end of ADC1 calibration */
           while(ADC_GetCalibrationStatus(ADC1));
         ADC_SoftwareStartConvCmd(ADC1, ENABLE);
}
void SysInit_DMA(void)
{
         DMA_InitTypeDef DMA_InitStructure;
         /* Enable DMA1 clock */
           RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
           /* DMA1 channel1 configuration ----------------------------------------------*/
           DMA_DeInit(DMA1_Channel1);
           DMA_InitStructure.DMA_PeripheralBaseAddr = ADC1_DR_Address;
           DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)ADCConvertedValue;
           DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
           DMA_InitStructure.DMA_BufferSize = 7;
           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 DMA1 channel1 */
           DMA_Cmd(DMA1_Channel1, ENABLE);
}

//******************************************************************************************
//AD采集
//每10MS调用
//******************************************************************************************
void ADC_Scan(void)
{
         Filter_Buf00[Filter_Pointer] = (u16)(ADCConvertedValue[0]>>2);
         Filter_Buf01[Filter_Pointer] = (u16)(ADCConvertedValue[1]>>2);
         Filter_Buf02[Filter_Pointer] = (u16)(ADCConvertedValue[2]>>2);
         Filter_Buf03[Filter_Pointer] = (u16)(ADCConvertedValue[3]>>2);
         Filter_Buf05[Filter_Pointer] = (u16)(ADCConvertedValue[4]>>2);
         Filter_Buf04[Filter_Pointer] = (u16)(ADCConvertedValue[5]>>2);
         Filter_Buf06[Filter_Pointer] = (u16)(ADCConvertedValue[6]>>2);
         Filter_Pointer++;
         if(Filter_Pointer >= 10) //去极值求平均        Filter_Remove_Extremum         
         {
                 Filter_Pointer = 0;
                 Aircondition.S_InTemp = Avr_Filter(Filter_Buf0,Filter_Remove_Extremum(Filter_Buf00));
         //        Aircondition.S_OutTemp = Avr_Filter(Filter_Buf1,Filter_Remove_Extremum(Filter_Buf01));
                 Aircondition.S_Def0Temp = Avr_Filter(Filter_Buf2,Filter_Remove_Extremum(Filter_Buf02));
         //        Aircondition.S_LNTemp = Avr_Filter(Filter_Buf3,Filter_Remove_Extremum(Filter_Buf03));
                 Aircondition.S_VOL = Avr_Filter(Filter_Buf4,Filter_Remove_Extremum(Filter_Buf04));
         //        Aircondition.S_PTC1Temp = Avr_Filter(Filter_Buf5,Filter_Remove_Extremum(Filter_Buf05));
         //        Aircondition.S_PTC2Temp = Avr_Filter(Filter_Buf6,Filter_Remove_Extremum(Filter_Buf06));
//                ADC_AnalogToDigtal();
         }
}