请香版主和各位指点下 STM32 AD采样偏差很大

只看该作者 · 2011-8-15 15:49

情况是这样的， STM32 的采样我现在PC0-PC3 PA1，5个通道采样
其他四个PC口的都正常，但是PA1的通道始终不对，电压我量了到片子这边的是1.2V 比如，但我读出来PA1的才0.7几V差的太远了不知道什么原因啊，量了 1.2的确是进到单片机了，软件配置查了一样的配置其他通道都正常，PA1用的是通道1 也是固件库里用的，您给分析下什么毛病啊

部分配置如下：

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 = 100;
  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);
DMA_ITConfig(DMA1_Channel1, DMA_IT_TC, ENABLE); //DMA通道1传输完成中断
  /* Enable DMA1 channel1 */
  //DMA_Cmd(DMA1_Channel1, ENABLE);//以前在这里启用DMA，出现通道错乱
   /* ADC1 configuration ------------------------------------------------------*/
  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 = 5;//通道的数目
  ADC_Init(ADC1, &ADC_InitStructure);
/* ADC1 regular channel14 configuration */
  ADC_RegularChannelConfig(ADC1, ADC_Channel_10, 1, ADC_SampleTime_55Cycles5);//VDD1
  ADC_RegularChannelConfig(ADC1, ADC_Channel_11, 2, ADC_SampleTime_55Cycles5); //udrvs
  ADC_RegularChannelConfig(ADC1, ADC_Channel_12, 3, ADC_SampleTime_55Cycles5); //VDD
  ADC_RegularChannelConfig(ADC1, ADC_Channel_13, 4, ADC_SampleTime_55Cycles5); //vdch
  ADC_RegularChannelConfig(ADC1, ADC_Channel_1,  6, ADC_SampleTime_55Cycles5);//UR2 ADC_Channel1 是1通道的
  /* 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));
  /* Enable DMA1 channel1 */
  DMA_Cmd(DMA1_Channel1, ENABLE);
  /* Start ADC1 Software Conversion */
  ADC_SoftwareStartConvCmd(ADC1, ENABLE);

其他四个通道PC口的都正常，就是这个怎么都不对明明电压过去了，求教啊
谢谢