STM32F103RCT6+串口DMA方式接收定长数据

1.接收缓存数组初始化

#define USART_REC_LEN  			100  	//定义最大字节数 100
u8 USART_RX_BUF[USART_REC_LEN];     //接收缓冲,最大USART_REC_LEN个字节.

2.串口初始化

void uart_init(u32 bound)
{
  //GPIO端口设置
    GPIO_InitTypeDef GPIO_InitStructure;
	USART_InitTypeDef USART_InitStructure;
	NVIC_InitTypeDef NVIC_InitStructure;
	 
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA, 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
   
  //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  

  //Usart1 NVIC 配置
    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
	NVIC_Init(&NVIC_InitStructure);	//根据指定的参数初始化VIC寄存器
  
   //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;//一个停止位
	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);//开启串口接受中断
	USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);//使能DMA接收
  USART_Cmd(USART1, ENABLE);                    //使能串口1 
}

3.DMA配置

void Usart1_DMA_init()
{
    DMA_InitTypeDef DMA_InitStructure;
	  NVIC_InitTypeDef NVIC_InitStructure;
	
	  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); //DMA1 时钟使能
	
	  DMA_DeInit(DMA1_Channel5);//将DMA的通道5寄存器重设为缺省值  串口1对应的是DMA通道5(接收)
	  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&USART1->DR;//DMA外设UASRT1->DR基地址
    DMA_InitStructure.DMA_MemoryBaseAddr = (u32)USART_RX_BUF;//DMA内存基地址
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;//DMA方向  外设->内存
    DMA_InitStructure.DMA_BufferSize = sizeof(USART_RX_BUF);//DMA通道的DMA缓存的大小
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外设地址不增加
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//内存地址自增1
    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_Circular;
    //DMA_Mode_Normal（只传送一次）, DMA_Mode_Circular （不停地传送）
    DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;//(DMA传送优先级为中等)
    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(DMA1_Channel5, &DMA_InitStructure);//初始化DMA1 通道5
    DMA_Cmd(DMA1_Channel5, ENABLE);  //启动DMA传输
	
	  //DMA发送中断配置
	  NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel5_IRQn;
	  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;//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
	  NVIC_Init(&NVIC_InitStructure);	//根据指定的参数初始化VIC寄存器 	
		
		DMA_ITConfig(DMA1_Channel5, DMA_IT_TC, ENABLE);//使能DMA传输完成中断
}

 4.DMA中断服务程序

void DMA1_Channel5_IRQHandler(void)
{
if(DMA_GetFlagStatus(DMA1_FLAG_TC5)==SET)
   {
        DMA_ClearFlag(DMA1_FLAG_TC5);//清中断标志，否则会一直中断
			  printf("进入DMA发送中断！\r\n");       
   }
}

可见，串口每接收100个字节产生一次DMA中断！