DMA采集ADC可以节省在主函数中的时间占用 为CPU减少负担

在代码实现过程中，DMA的配置需要在ADC配置之前，不然是不成功的

如下是adc.c

#include "adc.h"
#include "stm32f4xx.h"


__IO uint16_t ADCDualConvertedValue[4];

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

   /* Enable ADC1, DMA2 and GPIO clocks ****************************************/
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2 | RCC_AHB1Periph_GPIOC, ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);

    /* DMA2 Stream0 channe0 configuration **************************************/
    DMA_DeInit(DMA2_Stream0);
    DMA_InitStructure.DMA_Channel = DMA_Channel_0; 
    DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&ADCDualConvertedValue;
    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&(ADC1->DR);
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
    DMA_InitStructure.DMA_BufferSize = 4;
    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_FIFOMode_Enable;         
    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);

    /* Configure ADC1 Channe0 pin as analog input ******************************/
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0| GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3;
    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_Div2;
    ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_Disabled;//ADC_DMAAccessMode_1;
    ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;
    ADC_CommonInit(&ADC_CommonInitStructure);   

    /* ADC1 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_DataAlign = ADC_DataAlign_Right;
    ADC_InitStructure.ADC_NbrOfConversion = 4;
    ADC_Init(ADC1, &ADC_InitStructure);

    /* ADC1 regular channel configuration ******************************************/
    ADC_RegularChannelConfig(ADC1, ADC_Channel_10, 1, ADC_SampleTime_56Cycles);
    ADC_RegularChannelConfig(ADC1, ADC_Channel_11, 2, ADC_SampleTime_56Cycles);
    ADC_RegularChannelConfig(ADC1, ADC_Channel_12, 3, ADC_SampleTime_56Cycles);
    ADC_RegularChannelConfig(ADC1, ADC_Channel_13, 4, ADC_SampleTime_56Cycles);    

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

    /* Enable ADC3 DMA */
    ADC_DMACmd(ADC1, ENABLE);

    /* Enable ADC3 */
    ADC_Cmd(ADC1, ENABLE);

    ADC_SoftwareStartConv(ADC1);
}


uint16_t GET_ADC(u8 Channel,u8 times)
{
    u32 temp_val=0;
    u8 t;
    for(t=0;t<times;t++)
    {
        temp_val+=ADCDualConvertedValue[Channel];
        
    }
    return temp_val/times;
}

如下是 ADC.h

#ifndef _ADC_H
#define _ADC_H
#include "sys.h"

void ADCInit(void);
uint16_t GET_ADC(u8 Channel,u8 times);

#endif

想要获取第一通道的ADC值，取五次平均数

GET_ADC(0,5);