Lập trình ADC DMA Stm32F4

Như bài viết trước mình ứng dụng ADC chế độ bình thường ,

Nếu các bạn cần tốc độ cao nên dùng Chế độ ADC DMA 

Hàm Cài đặt ADC dùng DMA

#define     ADC1_DR_ADDRESS    ((uint32_t)0x4001204C)

void Config_ADC1_DMA(void)
{
  ADC_InitTypeDef       ADC_InitStructure;
  ADC_CommonInitTypeDef ADC_CommonInitStructure;
  DMA_InitTypeDef       DMA_InitStructure;
  GPIO_InitTypeDef      GPIO_InitStructure;

  /* Enable ADC3, DMA2 and GPIO clocks ****************************************/
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2 | RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOC, ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);

  /* DMA2 Stream0 channel0 configuration **************************************/
  DMA_InitStructure.DMA_Channel = DMA_Channel_0;  
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC1_DR_ADDRESS;
  DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&_ADC1_Value;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
  DMA_InitStructure.DMA_BufferSize = 6;
  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_FIFOMode = DMA_FIFOMode_Disable;         
  DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
  DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
  DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
  DMA_Init(DMA2_Stream0, &DMA_InitStructure);
  DMA_Cmd(DMA2_Stream0, ENABLE);
//    config_ngat_dma();// cau hinh ngat dma phai dat sau lenh enable kenh dma.

  /* Configure ADC1 Channel7 pin as analog input ******************************/

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_2|GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
  GPIO_Init(GPIOC, &GPIO_InitStructure);
  /* ADC Common Init **********************************************************/
  ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;
  ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div8;
  ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_Disabled;//ADC_DMAAccessMode_1;//
  ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_10Cycles;
  ADC_CommonInit(&ADC_CommonInitStructure);

  /* ADC3 Init ****************************************************************/
  ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
  ADC_InitStructure.ADC_ScanConvMode = ENABLE;
  ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
  ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
  ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T1_CC1;
  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
  ADC_InitStructure.ADC_NbrOfConversion = 6;
  ADC_Init(ADC1, &ADC_InitStructure);

  /* ADC3 regular channel7 configuration *************************************/
    #define sample_time_adc1 ADC_SampleTime_3Cycles
    ADC_RegularChannelConfig(ADC1, ADC_Channel_10, 1, ADC_SampleTime_3Cycles);
    ADC_RegularChannelConfig(ADC1, ADC_Channel_11, 2, ADC_SampleTime_3Cycles);
    ADC_RegularChannelConfig(ADC1, ADC_Channel_12, 3, ADC_SampleTime_3Cycles);
    ADC_RegularChannelConfig(ADC1, ADC_Channel_13, 4, ADC_SampleTime_3Cycles);
  ADC_RegularChannelConfig(ADC1, ADC_Channel_14, 5, ADC_SampleTime_3Cycles);
    ADC_RegularChannelConfig(ADC1, ADC_Channel_15, 6, ADC_SampleTime_3Cycles);
//    ADC_RegularChannelConfig(ADC1, ADC_Channel_6, 7, sample_time_adc1);
//    ADC_RegularChannelConfig(ADC1, ADC_Channel_7, 8, sample_time_adc1); // cac so rank la so thu tu chuyen doi adc 

 /* Enable DMA request after last transfer (Single-ADC mode) */
  ADC_DMARequestAfterLastTransferCmd(ADC1, ENABLE);
//ADC_MultiModeDMARequestAfterLastTransferCmd(ENABLE);
  /* Enable ADC1 DMA */
  ADC_DMACmd(ADC1, ENABLE);

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

ở đây giá trị lưu vào 6 biến _ADC1_Value

Các bạn cần lấy giá trị nào lấy từng trong thanh ghi lưu biến _ADC1_Value

Các giá trị ADC sẽ nhảy liên tục cần giảm nhiễu các bạn có thể lấy trung bình hoặc Dùng thuật toán