STM32F030的严重问题求救！！

只看该作者 · 2015-6-9 11:59

在使用STM32F030K6T6时，现在只使用了ADC0和ADC1（PA0和PA1两个引脚），发现只要置位具有ADC功能的其他IO口中的任意一个（设置为推挽输出），正在采样的ADC引脚（PA0和PA1）就会被附加上一个26K左右的方波信号，幅值大概在2~3V。
将选中的ADC引脚（PA0和PA1引脚）悬空，这个现象照样存在。ADC,DMA的代码使用DISCOVERY的例程，初始化如下：

void ADC_CH_DMA_Config(void)
{
  ADC_InitTypeDef    ADC_InitStructure;
  DMA_InitTypeDef    DMA_InitStructure;
  GPIO_InitTypeDef GPIO_InitStructure;
  /* ADC1 DeInit */
  ADC_DeInit(ADC1);

  /* ADC1 Periph clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
  /* DMA1 clock enable */
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1 , ENABLE);

GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_0 | GPIO_Pin_1 ;
  GPIO_InitStructure.GPIO_Mode  =  GPIO_Mode_AN;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;
  //GPIO_InitStructure.GPIO_Speed =  GPIO_Speed_2MHz;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA,  &GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_2 | GPIO_Pin_3 ;
  GPIO_InitStructure.GPIO_Mode  =  GPIO_Mode_OUT;
  GPIO_InitStructure.GPIO_OType =  GPIO_OType_PP;
  GPIO_InitStructure.GPIO_Speed =  GPIO_Speed_2MHz;
  //GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA,  &GPIO_InitStructure);

  /* DMA1 Channel1 Config */
  DMA_DeInit(DMA1_Channel1);
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC1_DR_Address;
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)RegularConvData_Tab;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
  DMA_InitStructure.DMA_BufferSize = 2;
  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);

  /* DMA1 Channel1 enable */
  DMA_Cmd(DMA1_Channel1, ENABLE);

  /* ADC DMA request in circular mode */
  ADC_DMARequestModeConfig(ADC1, ADC_DMAMode_Circular);

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

  /* Initialize ADC structure */
  ADC_StructInit(&ADC_InitStructure);

  /* Configure the ADC1 in continous mode withe a resolutuion equal to 12 bits  */
  ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
  ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
  ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
  ADC_InitStructure.ADC_ScanDirection = ADC_ScanDirection_Backward;
  ADC_Init(ADC1, &ADC_InitStructure);

  /* Convert the ADC1 temperature sensor  with 55.5 Cycles as sampling time */
  ADC_ChannelConfig(ADC1, ADC_Channel_0 , ADC_SampleTime_55_5Cycles);
  ADC_TempSensorCmd(ENABLE);

  /* Convert the ADC1 Vref  with 55.5 Cycles as sampling time */
  ADC_ChannelConfig(ADC1, ADC_Channel_0 , ADC_SampleTime_55_5Cycles);
  ADC_VrefintCmd(ENABLE);

  /* ADC Calibration */
  ADC_GetCalibrationFactor(ADC1);

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

  /* Wait the ADRDY falg */
  while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_ADRDY));

  /* ADC1 regular Software Start Conv */
  ADC_StartOfConversion(ADC1);
}

我只要将PA2,或者PA3在初始化时做如下置位：
  ADC_CH_DMA_Config();
  GPIO_SetBits(GPIOA, GPIO_Pin_3);

则PA0和PA1引脚上就会出现方波信号。