DMA（硬件加速方法）一般用于幫運(yùn)比較大的數(shù)據(jù)（如：攝像頭數(shù)據(jù)圖像傳輸），寄存器-》DMA-》RAM 或者?RAM-》DMA-》寄存器提高CPU的工作效率

源碼--

#include "myhead.h"
#include "adc.h"#include "delay.h"#include "usart.h"
extern u16 ADC1_Value;u16 ADC1_Value;void DMA_init(void)
{GPIO_InitTypeDef   GPIO_InitStructure;ADC_InitTypeDef       ADC_InitStructure;ADC_CommonInitTypeDef ADC_CommonInitStructure;DMA_InitTypeDef       DMA_InitStructure;//1.時(shí)鐘使能ADC1 GPIOARCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);//1分頻RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);//2分頻RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE);//1分頻//DMA2初始化DMA_InitStructure.DMA_Channel =  DMA_Channel_0;  //通道0DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&(ADC1->DR); //搬運(yùn)的起始地址DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&ADC1_Value; //搬運(yùn)的目的地址DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;   //DMA搬運(yùn)的方向DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;   //設(shè)置搬運(yùn)起始點(diǎn)到目的地發(fā)數(shù)據(jù)寬度DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;   //字節(jié)大小  半個(gè)字節(jié)DMA_InitStructure.DMA_BufferSize = 1;    //設(shè)置緩存塊數(shù)DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; //設(shè)置地址自動(dòng)遞增  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Disable;   DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;     //DMA搬運(yùn)模式 Nomal Circular循環(huán)DMA_InitStructure.DMA_Priority = DMA_Priority_High;   //觸發(fā)優(yōu)先級(jí)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);  //使能DMAGPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;//不需要上下拉電阻GPIO_Init(GPIOA, &GPIO_InitStructure);//3.ADC的公共部分配置ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;//獨(dú)立模式，雙重模式，三重模式ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div4;  //84MHZ---/4 給到具體ADC  21MHZ<=36MHZADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_Disabled;  //多重ADC模式有關(guān)，一般獨(dú)立ADC都不需要開(kāi)啟ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;//多重ADC模式的采樣間隔ADC_CommonInit(&ADC_CommonInitStructure);//4.指定ADC配置ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;  //精度選擇ADC_InitStructure.ADC_ScanConvMode = DISABLE;           //掃描模式選擇   開(kāi)掃描/關(guān)掃描    單個(gè)ADC開(kāi)了多個(gè)通道才要掃描模式ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;      //連續(xù)轉(zhuǎn)換模式  開(kāi)/關(guān)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 = 1;   //待轉(zhuǎn)換的通道數(shù)量    如果adc通道開(kāi)多個(gè)（adc1，adc3），通道數(shù)量跟數(shù)量一樣多，上面掃描模式就得開(kāi)ADC_Init(ADC1, &ADC_InitStructure);/* Enable DMA request after last transfer (Single-ADC mode) */  //ADC1->CR2  第9bit DDS位  中文手冊(cè)276頁(yè)ADC_DMARequestAfterLastTransferCmd(ADC1, ENABLE);/* Enable ADC3 DMA *///ADC1->CR2  第8bit DMA位  中文手冊(cè)276頁(yè)ADC_DMACmd(ADC1, ENABLE);//5.通道規(guī)則設(shè)置--設(shè)置adc通道的轉(zhuǎn)換順序ADC_RegularChannelConfig(ADC1, ADC_Channel_5, 1, ADC_SampleTime_3Cycles);//ADC_SampleTime_3Cycles通道轉(zhuǎn)換速度，等級(jí)越高轉(zhuǎn)換速度越快//6.使能ADC模塊ADC_Cmd(ADC1,ENABLE);
}int main(void)
{adc_init();usart1_init(9600);DMA_init();ADC_SoftwareStartConv(ADC1);   //ADC通道配置必須放DMA_init/adc_init()后面while(1){//3.3v/4096 =xV/ADC1->DRprintf("%.2fv\r\n",ADC1_Value*3.3/4095);  //不斷讀取ADC1的轉(zhuǎn)換結(jié)果  轉(zhuǎn)換成電壓值  (.2f表示double類型小數(shù)點(diǎn)后兩位打印結(jié)果）delay_ms(1000);}}

DMA2支持搬運(yùn)的外設(shè)有如圖