STM32串口DMA发送中断配置

本文以STM32F1xx的串口1为例，简单呈现下使用DMA中断连续发送的代码
串口DMA配置一般能够分为2个部分：
1.串口配置
2.DMA配置

1. 串口配置

void UART1_Init(u32 bound){
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
	
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA|RCC_APB2Periph_AFIO, ENABLE);	//使能USART1，GPIOA时钟
  
	//USART1_TX GPIOA.9
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; //PA.9
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;	//复用推挽输出
GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIOA.9

NVIC_Init(&NVIC_InitStructure);	//根据指定的参数初始化VIC寄存器 
  //USART1_RX GPIOA.10初始化
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;//PA10
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//浮空输入
GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIOA.10 

NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ;//抢占优先级3
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;		//子优先级3
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;			//IRQ通道使能 
//USART 初始化设置
USART_InitStructure.USART_BaudRate = bound;//串口波特率
USART_InitStructure.USART_WordLength = USART_WordLength_8b;//字长为8位数据格式
USART_InitStructure.USART_StopBits = USART_StopBits_1;//一个中止位
USART_InitStructure.USART_Parity = USART_Parity_No;//无奇偶校验位
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//无硬件数据流控制
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;	//收发模式

USART_Init(USART1, &USART_InitStructure); //初始化串口1
USART_ITConfig(USART1,USART_IT_IDLE,ENABLE);  //使能空闲中断
USART_Cmd(USART1, ENABLE);                    //使能串口1 
}

2.DMA配置
本代码封装了下DMA配置

void DMA_Config(DMA_Channel_TypeDef*DMA_CHx,u32 cpar,u32 cmar,u32 dma_dir,u32 priority,u16 bufsize)
{
	DMA_InitTypeDef DMA_InitStructure;
 	RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);	//使能DMA传输
  	DMA_DeInit(DMA_CHx);   //将DMA的通道1寄存器重设为缺省值
	DMA_InitStructure.DMA_PeripheralBaseAddr = cpar;  //DMA外设ADC基地址
	DMA_InitStructure.DMA_MemoryBaseAddr = cmar;  //DMA内存基地址
	DMA_InitStructure.DMA_DIR = dma_dir;  //数据传输方向，从内存读取发送到外设
	DMA_InitStructure.DMA_BufferSize = bufsize;  //DMA通道的DMA缓存的大小
	DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;  //外设地址寄存器不变
	DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;  //内存地址寄存器递增
	DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;  //数据宽度为8位
	DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte; //数据宽度为8位
	DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;  //工做在正常缓存模式
	DMA_InitStructure.DMA_Priority = priority; //DMA通道 x拥有中优先级 
	DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;  //DMA通道x没有设置为内存到内存传输
	DMA_Init(DMA_CHx, &DMA_InitStructure);  
}

void UART_DMA_Config{
NVIC_InitTypeDef NVIC_InitStructure;

 //配置串口1发送DMA
DMA_Config(DMA1_Channel4,(u32)&USART1->DR,(u32)USART1_TX_BUF,DMA_DIR_PeripheralDST,DMA_Priority_Medium,0);//DMA1通道4,外设为串口1Tx,存储器为USART_TX_BUF 
//配置串口1接收DMA
DMA_Config(DMA1_Channel5,(u32)&USART1->DR,(u32)USART1_RX_BUF,DMA_DIR_PeripheralSRC,DMA_Priority_Medium,0);//DMA1通道5,外设为串口1Rx,存储器为USART_RX_BUF

NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel4_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0 ;//抢占优先级3
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;		//子优先级3
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;			//IRQ通道使能
NVIC_Init(&NVIC_InitStructure);	//根据指定的参数初始化VIC寄存器

DMA_ITConfig(DMA1_Channel4,DMA_IT_TC,ENABLE);	//开USART1 Tx DMA中断
USART_DMACmd(USART1,USART_DMAReq_Tx,ENABLE);  	//使能串口3的DMA接收
USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);  	//使能串口3的DMA接收
}

最后是中断函数

void USART1_IRQHandler(void)           	//串口1中断服务程序
{
	if(USART_GetITStatus(USART1, USART_IT_IDLE) != RESET)  
	{  
		USART1_RX_CNT = USART1->SR;  
		USART1_RX_CNT = USART1->DR; //清USART_IT_IDLE标志
		
		DMA_Cmd(DMA1_Channel5,DISABLE);  
		USART_ITConfig(USART1, USART_IT_IDLE, DISABLE); //静止中断，防覆盖
		USART1_RX_CNT = USART1_REC_LEN - DMA_GetCurrDataCounter(DMA1_Channel5);  
			
		DMA_SetCurrDataCounter(DMA1_Channel5,USART1_REC_LEN);  
		DMA_Cmd(DMA1_Channel5,ENABLE);  
		USART_ITConfig(USART1, USART_IT_IDLE, ENABLE); 
	}   
}

 //串口1 TX DMA终端
void DMA1_Channel4_IRQHandler(void)   
{
	if(DMA_GetITStatus(DMA1_FLAG_TC4))
	{
		DMA_ClearFlag(DMA1_FLAG_TC4);
		if(Txed_Num > Max_Tx_Cnt)
		{			
			Txed_Num = 0;
			return;
		}
		TX_DATA(DATA_Len);
		Txed_Num = Txed_Num + 1;
	}
}

//DMA发送代码
void TX_DATA(u8 len)
{
	while(DMA_GetCurrDataCounter(DMA1_Channel4)!=0);	//等待通道7传输完成 
	DMA_Cmd(DMA1_Channel4, DISABLE );  //关闭 指示的通道 
	DMA_SetCurrDataCounter(DMA1_Channel4,len);//DMA通道的DMA缓存的大小 
	DMA_Cmd(DMA1_Channel4, ENABLE);           //开启DMA传输
}

总结
串口DMA发送中断配置时，易遗漏

DMA_ITConfig(DMA1_Channel4,DMA_IT_TC,ENABLE);

本例是DMA发送中断在 连续、分次发送 场景下的应用。