STM32 DMA 串口透传
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DMA 网上的解释一大堆，简单总结一下：
本文引用地址：https://www.eepw.com.cn/article/201611/318108.htmDMA处理过程全部是由硬件来实现的，速度很快！
DMA在专门的DMA控制下，实现高速外设与主存储期之间自动成批量的数据交换。
通常有两种交换方式：1独占总线方式 2周期挪用方式
DMA传送过程
DMA预处理
DMA数据传送
DMA结束处理将总线控制权交换给CPU
DMA内部寄存器
地址寄存器：存放DMA传输是储存单元地址
字节寄存器：存放DMA传输字节数
控制寄存器：存放CPU设定的DMA传输方式
状态寄存器：存放DMAC当前的状态
DMA外设地址：基地址+偏移地址
两种方法设定地址：
#defineUSART1_DR_Base 0x40013804
#defineUSART1_DR_Base (&(USART1->DR)) 觉得还是第二种方法比较直接
DMA两种中断触发方式：
DMA_IT_TC1传输完成中断：每次更新发生在计数>=设定值
DMA_IT_HT1传输过半中断：每次更新发生在计数>（设定值/2）
DMA_IT_GL1全局中断：（实验了几次和过半中断传输情况一致）
编程的时候根据DMA请求映像来判断通道号，然后找到目的地址和原地址基本上就算完事儿了。当然得分清是传输是外设和内存，内存和外设，内存和内存三种情况，会有 （DMA_InitTypeDef 结构体).DMA_M2M 进行设置。
下面是DMA串口收发简单例子，并没有用到FIFO精确收发，有时间再好好写写~
DMA_Configuration（）是DMA5通道 串口1接收通道配置函数
DMA_Configuration2（）是DMA4通道 串口1发送通道配置函数
对于发送 可以每当发送的时候 都执行DMA_Configuration2（），进行发送操作
对于接收 理应采用FIFO,对于接收数组进行处理，这里只是简单的接收，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 控制初始化函数* 入口参数：无* 出口参数：无* 说 明：* 调用方法：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 配置为通用推挽输出 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背光控制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背光关闭 }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目的地还是来源DMA_InitStructure.DMA_BufferSize = 5; //DMA缓存的大小 单位在下边设定DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; //外设地址寄存器不递增DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; //内存地址递增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; //工作在循环缓存模式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); //根据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半传输完成中断USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE); //使能USART1的接收DMA请求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目的地还是来源DMA_InitStructure.DMA_BufferSize = NbrOfDataToTransfer; //DMA缓存的大小 单位在下边设定DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; //外设地址寄存器不递增DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; //内存地址递增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 ; //工作在循环缓存模式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); //根据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传输完成中断USART_DMACmd(USART1,USART_DMAReq_Tx,ENABLE); //使能USART1的发送DMA请求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* 入口参数：无* 出口参数：无* 说 明：* 调用方法：无 / int main(void){int i,j;RCC_Configuration(); //系统时钟配置//TIM3_Configuration();NVIC_Configuration(); LED_Config(); USART1_Configration();DMA_Configuration(); //DMA_Configuration2();//LED控制配置// printf("Start DMA transmission!rn");//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：系统时钟配置为72MHZ* 入口参数：无* 出口参数：无* 说 明：* 调用方法：无 / void RCC_Configuration(void){ SystemInit();}void DMA1_Channel5_IRQHandler(void){u8 end;int i; printf("Start DMA transmission!rn");/ 全传输完成*/// if(DMA_GetITStatus(DMA1_IT_TC5))// { // end = DMA_GetCurrDataCounter(DMA1_Channel5);// DMA_ClearITPendingBit(DMA1_IT_GL5);///* 清中断源// DMA_ClearFlag(DMA1_FLAG_TC5); // // printf("AA%dAA:", end);// printf("%srn", SendBuff);// for(i=0;i<100000;i++); // }/// 半传输完成*/if(DMA_GetITStatus(DMA1_FLAG_HT5)){ end = DMA_GetCurrDataCounter(DMA1_Channel5);DMA_ClearITPendingBit(DMA1_IT_GL5);///* 清中断源DMA_ClearFlag(DMA1_IT_TC5); printf("AA%dAA:", end);printf("%srn", 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!");}}
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