一向没有好好的捣鼓过ＤＭＡ,在调BLE项意图时分，遇到了DMA串口传输的问题，悲伤流涕甚长期!!!
DMA 网上的解说一大堆，简略总结一下：
DMA处理进程全部是由硬件来完结的，速度很快！
DMA在专门的DMA操控下，完结高速外设与主存储期之间主动成批量的数据交流。
一般有两种交流办法：1独占总线办法 2周期移用办法
DMA传送进程
DMA预处理
DMA数据传送
DMA完毕处理将总线操控权交流给CPU
DMA内部寄存器
地址寄存器：寄存DMA传输是贮存单元地址
字节寄存器：寄存DMA传输字节数
操控寄存器：寄存CPU设定的DMA传输办法
状况寄存器：寄存DMAC当时的状况
DMA外设地址：基地址+偏移地址
两种办法设定地址：
#defineUSART1_DR_Base 0x40013804
#defineUSART1_DR_Base (&(USART1->DR)) 觉得仍是第二种办法比较直接
DMA两种中止触发办法：
DMA_IT_TC1传输完结中止：每次更新发生在计数>=设定值
DMA_IT_HT1传输过半中止：每次更新发生在计数>（设定值/2）
DMA_IT_GL1大局中止：（试验了几回和过半中止传输状况共同）
编程的时分依据DMA恳求映像来判别通道号，然后找到意图地址和原地址基本上就算完事儿了。当然得辨明是传输是外设和内存，内存和外设，内存和内存三种状况，会有 （DMA_InitTypeDef 结构体).DMA_M2M 进行设置。
下面是DMA串口收发简略比如，并没有用到FIFO准确收发，有时间再好好写写~
DMA_Configuration（）是DMA5通道 串口1接纳通道装备函数
DMA_Configuration2（）是DMA4通道 串口1发送通道装备函数
关于发送 能够每逢发送的时分 都碑文DMA_Configuration2（），进行发送操作
关于接纳 理应选用FIFO,关于接纳数组进行处理，这儿仅仅简略的接纳，没有进一步处理
/* Includes ------------------------------------------------------------------*/#include "stm32f10x.h"#include "stm32f10x_tim.h" #include "stm32f10x_rcc.h"#include "stm32f10x_map.h" #include "stm32f10x_it.h" #include "misc.h" #include "bsp_timer.h"#include "stm32f10x_usart.h"#include "stm32f10x_dma.h"#include "stdio.h"#define SENDBUFF_SIZE 10vu8 SendBuff[SENDBUFF_SIZE]={0};vu8 TxBuffer[] = "hello xiao lei !!! ";vu8 NbrOfDataToTransfer = sizeof(TxBuffer)-1;GPIO_InitTypeDef GPIO_InitStructure;#define LED1_ON GPIO_SetBits(GPIOB, GPIO_Pin_5); #define LED1_OFF GPIO_ResetBits(GPIOB, GPIO_Pin_5); #define LED2_ON GPIO_SetBits(GPIOD, GPIO_Pin_6); #define LED2_OFF GPIO_ResetBits(GPIOD, GPIO_Pin_6); #define LED3_ON GPIO_SetBits(GPIOD, GPIO_Pin_3); #define LED3_OFF GPIO_ResetBits(GPIOD, GPIO_Pin_3); void RCC_Configuration(void);void LED_Config(void);void Delay(__IO uint32_t nCount);int fputc(int ch, FILE *f){USART_SendData(USART1, (u8) ch);while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET){}return ch;}/* 名 称：void LED_Config(void)* 功 能：LED 操控初始化函数* 进口参数：无* 出口参数：无* 说 明：* 调用办法：无 / void LED_Config(void){RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOD , ENABLE); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //LED1 V6 //将V6,V7,V8 装备为通用推挽输出 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //口线翻转速度为50MHzGPIO_Init(GPIOB, &GPIO_InitStructure); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6|GPIO_Pin_3; //LED2, LED3 V7 V8GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_Init(GPIOD, &GPIO_InitStructure);GPIO_Init(GPIOD, &GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13; //LCD背光操控GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_Init(GPIOD, &GPIO_InitStructure);GPIO_ResetBits(GPIOD, GPIO_Pin_13); //LCD背光封闭 }void USART1_Configration(){USART_InitTypeDef USART_InitStructure; GPIO_InitTypeDef GPIO_InitStructure;RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_USART1, ENABLE);//USART1_TXGPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;GPIO_Init(GPIOA, &GPIO_InitStructure);//USART1_RXGPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;GPIO_Init(GPIOA, &GPIO_InitStructure);USART_InitStructure.USART_BaudRate = 9600;USART_InitStructure.USART_WordLength = USART_WordLength_8b;USART_InitStructure.USART_StopBits = USART_StopBits_1;USART_InitStructure.USART_Parity = USART_Parity_No;USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;USART_InitStructure.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;USART_Init(USART1, &USART_InitStructure);USART_Cmd(USART1, ENABLE);}void DMA_Configuration(void){DMA_InitTypeDef DMA_InitStructure;NVIC_InitTypeDef NVIC_InitStructure;RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); //使能DMA传输DMA_DeInit(DMA1_Channel5);DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&(USART1->DR));DMA_InitStructure.DMA_MemoryBaseAddr = (u32)SendBuff;DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC; //外设作源头//外设是作为数据传输的意图地仍是来历DMA_InitStructure.DMA_BufferSize = 5; //DMA缓存的巨细 单位在下边设定DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; //外设地址寄存器不递加DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; //内存地址递加DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte; //外设字节为单位DMA_InitStructure.DMA_MemoryDataSize = DMA_PeripheralDataSize_Byte; //内存字节为单位DMA_InitStructure.DMA_Mode = DMA_Mode_Circular; //作业在循环缓存形式DMA_InitStructure.DMA_Priority = DMA_Priority_High; //4优先级之一的(高优先) VeryHigh/High/Medium/LowDMA_InitStructure.DMA_M2M = DMA_M2M_Disable; //非内存到内存DMA_Init(DMA1_Channel5, &DMA_InitStructure); //依据DMA_InitStruct中指定的参数初始化DMA的通道1寄存器DMA_ITConfig(DMA1_Channel5, DMA_IT_HT, ENABLE); //DMA5半传输完结中止USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE); //使能USART1的接纳DMA恳求DMA_Cmd(DMA1_Channel5, ENABLE); DMA_ClearFlag(DMA1_FLAG_TC5); NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel5_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure);}void DMA_Configuration2(void){DMA_InitTypeDef DMA_InitStructure;NVIC_InitTypeDef NVIC_InitStructure;RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); //使能DMA传输DMA_DeInit(DMA1_Channel4);DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&(USART1->DR));DMA_InitStructure.DMA_MemoryBaseAddr = (u32)TxBuffer;DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST ; //外设作源头//外设是作为数据传输的意图地仍是来历DMA_InitStructure.DMA_BufferSize = NbrOfDataToTransfer; //DMA缓存的巨细 单位在下边设定DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; //外设地址寄存器不递加DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; //内存地址递加DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte; //外设字节为单位DMA_InitStructure.DMA_MemoryDataSize = DMA_PeripheralDataSize_Byte; //内存字节为单位DMA_InitStructure.DMA_Mode = DMA_Mode_Normal ; //作业在循环缓存形式DMA_InitStructure.DMA_Priority = DMA_Priority_High; //4优先级之一的(高优先) VeryHigh/High/Medium/LowDMA_InitStructure.DMA_M2M = DMA_M2M_Disable; //内存到非内存DMA_Init(DMA1_Channel4, &DMA_InitStructure); //依据DMA_InitStruct中指定的参数初始化DMA的通道1寄存器DMA_ITConfig(DMA1_Channel4, DMA_IT_TC , ENABLE); //DMA4传输完结中止USART_DMACmd(USART1,USART_DMAReq_Tx,ENABLE); //使能USART1的发送DMA恳求DMA_Cmd(DMA1_Channel4, ENABLE); DMA_ClearFlag(DMA1_FLAG_TC4); NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel4_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure);}/* 名 称：int main(void)* 功 能：主函数* 进口参数：无* 出口参数：无* 说 明：* 调用办法：无 / int main(void){int i,j;RCC_Configuration(); //体系时钟装备//TIM3_Configuration();NVIC_Configuration(); LED_Config(); USART1_Configration();DMA_Configuration(); //DMA_Configuration2();//LED操控装备// printf("Start DMA transmission!\r\n");//LED1_ON ;for(i=0;i<1000000;i++);// for(j=0;j<20;j++); DMA_Configuration2();while (1){}}/* 名 称：void RCC_Configuration(void)* 功 能：体系时钟装备为72MHZ* 进口参数：无* 出口参数：无* 说 明：* 调用办法：无 / void RCC_Configuration(void){ SystemInit();}void DMA1_Channel5_IRQHandler(void){u8 end;int i; printf("Start DMA transmission!\r\n");/ 全传输完结*/// if(DMA_GetITStatus(DMA1_IT_TC5))// { // end = DMA_GetCurrDataCounter(DMA1_Channel5);// DMA_ClearITPendingBit(DMA1_IT_GL5);///* 清中止源// DMA_ClearFlag(DMA1_FLAG_TC5); // // printf("AA%dAA:", end);// printf("%s\r\n", SendBuff);// for(i=0;i<100000;i++); // }/// 半传输完结*/if(DMA_GetITStatus(DMA1_FLAG_HT5)){ end = DMA_GetCurrDataCounter(DMA1_Channel5);DMA_ClearITPendingBit(DMA1_IT_GL5);///* 清中止源DMA_ClearFlag(DMA1_IT_TC5); printf("AA%dAA:", end);printf("%s\r\n", SendBuff);for(i=0;i<100000;i++); }//}void DMA1_Channel4_IRQHandler(void){if(DMA_GetITStatus(DMA1_IT_TC4)==SET){DMA_ClearFlag(DMA1_IT_TC4);//TCIE,TE,RE printf("AAAA!");}}
