STM32空闲中断+DMA解决接收不定长数据问题

串口的中断类型:

#define USART_IT_PE                          ((uint16_t)0x0028)
#define USART_IT_TXE                         ((uint16_t)0x0727)
#define USART_IT_TC                          ((uint16_t)0x0626)
#define USART_IT_RXNE                        ((uint16_t)0x0525)
#define USART_IT_IDLE                        ((uint16_t)0x0424)
#define USART_IT_LBD                         ((uint16_t)0x0846)
#define USART_IT_CTS                         ((uint16_t)0x096A)
#define USART_IT_ERR                         ((uint16_t)0x0060)
#define USART_IT_ORE                         ((uint16_t)0x0360)
#define USART_IT_NE                          ((uint16_t)0x0260)
#define USART_IT_FE                          ((uint16_t)0x0160)

USART_IT_PE 奇偶错误中断

USART_IT_TXE发送中断

USART_IT_TC 传输完成中断

USART_IT_RXNE 接收中断

USART_IT_IDLE 空闲总线中断

USART_IT_LBD LIN中断检测中断

USART_IT_CTS CTS中断

USART_IT_ERR 错误中断

该程序中用到的就是串口的空闲中断:当总线是一个字节周期内没有收到数据时触发

串口的配置如下:

void uart_init(u32 bound){
        GPIO_InitTypeDef GPIO_InitStructure;
	USART_InitTypeDef USART_InitStructure;
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA, ENABLE);	
	NVIC_InitTypeDef NVIC_InitStructure;
	 //IO口相关配置
 	USART_DeInit(USART1);  
        GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;//IO口速率
        GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; 
        GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
        GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
        GPIO_Init(GPIOA, &GPIO_InitStructure); 
        GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
        GPIO_Init(GPIOA, &GPIO_InitStructure);  
        //串口中断配置
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;		
        NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;			
	NVIC_Init(&NVIC_InitStructure);	
	USART_InitStructure.USART_Parity = USART_Parity_No;//没有奇偶校验位
	USART_InitStructure.USART_BaudRate = bound;       //波特率设置
	USART_InitStructure.USART_WordLength = USART_WordLength_8b;//8位数据位
	USART_InitStructure.USART_StopBits = USART_StopBits_1;//1位停止位
	USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//无硬件数据流配置
	USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;//串口收发模式
        USART_Init(USART1, &USART_InitStructure); 
        USART_ITConfig(USART1, USART_IT_IDLE, ENABLE);
        USART_Cmd(USART1, ENABLE);  
}  

串口中断配置:

void USART1_IRQHandler(void)                 
{
      if(USART_GetITStatus(USART1, USART_IT_IDLE) != RESET) 
{
       DMA_Cmd(DMA1_Channel5,DISABLE);
       recok=1;
       lenth=USART1->DR;//软件清空空闲中断标志位
       lenth=USART1->SR;
       lenth=32-DMA_GetCurrDataCounter(DMA1_Channel5);//获取当前接收的数据量 
       USART_RX_BUF[lenth]=0;//在buff最后加入空字符
       DMA1_Channel5->CNDTR=32;//重新设置传输量为32 
       DMA_Cmd(DMA1_Channel5,ENABLE);
    } 
} 

DMA配置:

void MYDMA_Config(DMA_Channel_TypeDef* DMA_CHx,u32 cpar,u32 cmar,u16 cndtr)
{
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);//使能DMA时钟

      DMA_DeInit(DMA_CHx);
      DMA1_MEM_LEN=cndtr;
      DMA_InitStructure.DMA_PeripheralBaseAddr = cpar;//外设地址
      DMA_InitStructure.DMA_MemoryBaseAddr = cmar; //内存地址
      DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC; //传输方向外设到内存
      DMA_InitStructure.DMA_BufferSize = cndtr;  //传输量
      DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外设地址不自增  
      DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; //内存地址自增
      DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte; 
      DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte; 
      DMA_InitStructure.DMA_Mode = DMA_Mode_Normal; //普通模式
      DMA_InitStructure.DMA_Priority = DMA_Priority_High;//高优先级
      DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
      DMA_Init(DMA_CHx, &DMA_InitStructure);  
} 

主函数中需要进行的配置:

 MYDMA_Config(DMA1_Channel5,(u32)&USART1->DR,(u32)USART_RX_BUF,32);//传输方向设置为USART1->DR到USART_RX_BUF 传输大小为32字节
 USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);//允许DMA请求
 DMA_Cmd(DMA1_Channel5,ENABLE);

当标志为recok位1时表示接受完成  在主函数中等待recok位1就可以了