ADC转换时间为什么不能达到1us

只看该作者 · 2014-8-22 10:02

直接上程序  时钟已经是56M
void ADC_Configuration(void)
{

/* DMA1 channel1 configuration ----------------------------------------------*/
  DMA_InitTypeDef DMA_InitStructure;

  DMA_DeInit(DMA1_Channel1);
  DMA_InitStructure.DMA_PeripheralBaseAddr = ADC1_DR_Address;
  DMA_InitStructure.DMA_MemoryBaseAddr = (u32)ADCConvertedValue;
  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_Word;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Word;
  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_Cmd(DMA1_Channel1, ENABLE);
/* 定义 ADC 初始化结构体 ADC_InitStructure */
ADC_InitTypeDef ADC_InitStructure;

/*
* 独立工作模式;
* 多通道扫描模式;
* 连续模数转换模式;
* 转换触发方式：转换由软件触发启动;
* ADC 数据右对齐 ;
* 进行规则转换的 ADC 通道的数目为1;
*/
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 = 2;
ADC_Init(ADC1, &ADC_InitStructure);
      /*配置ADC时钟，为PCLK2的8分频，即8MHz*/
RCC_ADCCLKConfig(RCC_PCLK2_Div4);

/* 设置 ADC1 使用8转换通道，采样时间为 55.5 周期 */
//ADC_RegularChannelConfig(ADC1, ADC_Channel_9, 1, ADC_SampleTime_55Cycles5);
   // ADC_RegularChannelConfig(ADC1, ADC_Channel_5, 2, ADC_SampleTime_55Cycles5);
      ADC_DMACmd(ADC1, ENABLE);

   ADC_InjectedSequencerLengthConfig(ADC1, 1);
      ADC_InjectedChannelConfig(ADC1,ADC_Channel_8,1,ADC_SampleTime_1Cycles5);

      ADC_ExternalTrigInjectedConvCmd(ADC1, ENABLE);
      ADC_ExternalTrigInjectedConvConfig(ADC1, ADC_ExternalTrigInjecConv_T1_CC4);//设置注入通道T1比较4中断触发
         /* Enable JEOC interupt */
      ADC_ITConfig(ADC1, ADC_IT_JEOC, ENABLE);
      RCC_ADCCLKConfig(RCC_PCLK2_Div4);
/* 使能 ADC1 */
ADC_Cmd(ADC1, ENABLE);

/* 复位 ADC1 的校准寄存器 */
ADC_ResetCalibration(ADC1);
/* 等待 ADC1 校准寄存器复位完成 */
while(ADC_GetResetCalibrationStatus(ADC1));

/* 开始 ADC1 校准 */
ADC_StartCalibration(ADC1);
/* 等待 ADC1 校准完成 */
while(ADC_GetCalibrationStatus(ADC1));

/* 启动 ADC1 转换 */
ADC_SoftwareStartConvCmd(ADC1, ENABLE);
}

只看该作者 · 2014-8-22 10:03

然后是注入通道的中断程序
void ADC1_2_IRQHandler(void)
{
  GPIO_WriteBit(GPIOA, GPIO_Pin_3, (BitAction)(1 - GPIO_ReadOutputDataBit(GPIOA, GPIO_Pin_3)));//取反
  //ADC_Injectre = ADC_GetInjectedConversionValue(ADC1, ADC_InjectedChannel_1);
  ADC_ClearITPendingBit(ADC1, ADC_IT_JEOC);
}