STM32的串口採用DMA方式接收數據測試

STM32的串口採用DMA方式接收數據測試

本文博客鏈接:http://blog.csdn.net/jdh99,作者:jdh,轉載請註明.

參考鏈接:http://www.amobbs.com/forum.php?mod=viewthread&tid=5511863&highlight=dma%E6%8E%A5%E6%94%B6

環境：

主機:WINXP

開發環境:MDK4.23

MCU:STM32F103CBT6

說明:

串口可以配置成用DMA的方式接收數據,不過DMA需要定長才能產生接收中斷,如何接收可變長度的數據呢?

方法有以下3種:

1.將RX腳與一路時鐘外部引腳相連,當串口一幀發完,即可利用此定時器產生超時中斷.這個實時性較高,可以做到1個字節實時監測.

2.不改變硬件,開啓一個定時器監控DMA接收,如果超時則產生中斷.這個實時性不高,因爲超時時間必須要大於需要接收幀的時間,精度不好控制.

3.STM32單片機有的串口可以監測總線是否處於空閒,如果空閒則產生中斷.可以用它來監測DMA接收是否完畢.這種方式實時性很高.

本文采用第3種方式.在波特率576000下大數據包衝擊證明可行.

源代碼:

//串口接收DMA緩存
#define UART_RX_LEN     128
extern uint8_t Uart_Rx[UART_RX_LEN];

//串口接收DMA緩存
uint8_t Uart_Rx[UART_RX_LEN] = {0};

//---------------------串口功能配置---------------------
    //打開串口對應的外設時鐘
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 , ENABLE);
    //串口發DMA配置
    //啓動DMA時鐘
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
    //DMA發送中斷設置
    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
    DMA_DeInit(DMA1_Channel4);
    //外設地址
    DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&USART1->DR);
    //內存地址
    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)Uart_Send_Buffer;
    //dma傳輸方向單向
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
    //設置DMA在傳輸時緩衝區的長度
    DMA_InitStructure.DMA_BufferSize = 100;
    //設置DMA的外設遞增模式，一個外設
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    //設置DMA的內存遞增模式
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    //外設數據字長
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    //內存數據字長
    DMA_InitStructure.DMA_MemoryDataSize = DMA_PeripheralDataSize_Byte;
    //設置DMA的傳輸模式
    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
    //設置DMA的優先級別
    DMA_InitStructure.DMA_Priority = DMA_Priority_High;
    //設置DMA的2個memory中的變量互相訪問
    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    DMA_Init(DMA1_Channel4,&DMA_InitStructure);
    DMA_ITConfig(DMA1_Channel4,DMA_IT_TC,ENABLE);

    //使能通道4
    //DMA_Cmd(DMA1_Channel4, ENABLE);

    //串口收DMA配置
    //啓動DMA時鐘
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
    //DMA1通道5配置
    DMA_DeInit(DMA1_Channel5);
    //外設地址
    DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&USART1->DR);
    //內存地址
    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)Uart_Rx;
    //dma傳輸方向單向
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
    //設置DMA在傳輸時緩衝區的長度
    DMA_InitStructure.DMA_BufferSize = UART_RX_LEN;
    //設置DMA的外設遞增模式，一個外設
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    //設置DMA的內存遞增模式
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    //外設數據字長
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    //內存數據字長
    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
    //設置DMA的傳輸模式
    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
    //設置DMA的優先級別
    DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
    //設置DMA的2個memory中的變量互相訪問
    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    DMA_Init(DMA1_Channel5,&DMA_InitStructure);

    //使能通道5
    DMA_Cmd(DMA1_Channel5,ENABLE);


    //初始化參數
    //USART_InitStructure.USART_BaudRate = DEFAULT_BAUD;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_InitStructure.USART_BaudRate = DEFAULT_BAUD;
    //初始化串口
    USART_Init(USART1,&USART_InitStructure);
    //TXE發送中斷,TC傳輸完成中斷,RXNE接收中斷,PE奇偶錯誤中斷,可以是多個
    //USART_ITConfig(USART1,USART_IT_RXNE,ENABLE);

    //中斷配置
    USART_ITConfig(USART1,USART_IT_TC,DISABLE);
    USART_ITConfig(USART1,USART_IT_RXNE,DISABLE);
    USART_ITConfig(USART1,USART_IT_IDLE,ENABLE);

    //配置UART1中斷
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3);
    NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;               //通道設置爲串口1中斷
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;       //中斷佔先等級0
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;              //中斷響應優先級0
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;                 //打開中斷
    NVIC_Init(&NVIC_InitStructure);

    //採用DMA方式發送
    USART_DMACmd(USART1,USART_DMAReq_Tx,ENABLE);
    //採用DMA方式接收
    USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);
    //啓動串口
    USART_Cmd(USART1, ENABLE);

//串口1接收中斷
void USART1_IRQHandler(void)
{
    uint32_t temp = 0;
    uint16_t i = 0;

    if(USART_GetITStatus(USART1, USART_IT_IDLE) != RESET)
    {
        //USART_ClearFlag(USART1,USART_IT_IDLE);
        temp = USART1->SR;
        temp = USART1->DR; //清USART_IT_IDLE標誌
        DMA_Cmd(DMA1_Channel5,DISABLE);

        temp = UART_RX_LEN - DMA_GetCurrDataCounter(DMA1_Channel5);
        for (i = 0;i < temp;i++)
        {
            Data_Receive_Usart = Uart_Rx[i];
            //啓動串口狀態機
            usart_state_run();
        }

        //設置傳輸數據長度
        DMA_SetCurrDataCounter(DMA1_Channel5,UART_RX_LEN);
        //打開DMA
        DMA_Cmd(DMA1_Channel5,ENABLE);
    }

    __nop();
}   
轉載地址：http://blog.csdn.net/jdh99/article/details/8444474

測試結果: