stm系列--USART-DMA应用

 

 

void uart_dma_init(u32 bound){
    //GPIO端口设置
   GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
     DMA_InitTypeDef        DMA_InitStructure;
    
     USART_DeInit(USART1);  //复位串口1
    
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);    //使能USART1，GPIOA时钟
    //USART1_TX   PA.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PA9
 
    //USART1_RX      PA.10
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;//浮空输入 GPIO_Mode_IN_FLOATING
    GPIO_Init(GPIOA, &GPIO_InitStructure);  //初始化PA10

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);    //使能USART1，GPIOA时钟
//USART 初始化设置
    USART_InitStructure.USART_BaudRate = bound;//一般设置为9600;
    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
  USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);//开启中断
   
     //Usart1 NVIC 配置

  NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2 ;//抢占优先级3
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;        //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发送中断设置*/
    NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel4_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
   
         /*DMA1通道4配置发送*/
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
    DMA_DeInit(DMA1_Channel4);
    DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&USART1->DR);
    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)USART_TX_BUF;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
    DMA_InitStructure.DMA_BufferSize = 200;
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    DMA_InitStructure.DMA_MemoryDataSize = DMA_PeripheralDataSize_Byte;
    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
    DMA_InitStructure.DMA_Priority = DMA_Priority_High;
    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    DMA_Init(DMA1_Channel4,&DMA_InitStructure);
    DMA_ITConfig(DMA1_Channel4,DMA_IT_TC,ENABLE);
    //DMA_Cmd(DMA1_Channel4, ENABLE);//使能通道4，一般发送的时候再使能
  //采用DMA方式发送
    USART_DMACmd(USART1,USART_DMAReq_Tx,ENABLE);
  USART_Cmd(USART1, ENABLE);                    //使能串口 

}

void USART1_IRQHandler(void)                    //串口1中断服务程序
    {
     u8 sbuf;
    if (USART_GetFlagStatus(USART1, USART_FLAG_ORE) != RESET)//注意！不能使用if(USART_GetITStatus(USART1, USART_IT_RXNE) != sbufET)来判断  
    {  
            sbuf=USART_ReceiveData(USART1);  
    } 
    if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)  //接收中断(接收到的数据必须是0xbb 结尾)
    {
        sbuf =USART_ReceiveData(USART1);//(USART1->DR);    //读取接收到的数据
        
        if( myusart.reflag==0)
        {
            myusart.timout=10;
            if(myusart.recount<_maxbuf) 
            {
                myusart.rcbuf[myusart.recount++]=sbuf;
            }
        }            
        USART_ClearITPendingBit(USART1,USART_IT_RXNE);                    
    } 
}

void uart_dma_send_enable(uint16_t size)
{
    DMA1_Channel4->CNDTR = (uint16_t)size; 
    DMA_Cmd(DMA1_Channel4, ENABLE);       
}