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