STM32——DMA接收和发送的实现

最近写程序，需要一段一段数据的接收，再通过其他串口发送出去。

老司机们建议用DMA通信，以节约CPU资源。然后，我听了，发现挺好用的。特此，把自己写的代码贴上了。

DMA发送接收的步骤如下：

1.初始化。

a.IO时钟+串口时钟+DMA时钟使能。

b.IO初始化

c.串口初始化

d.DMA初始化

e.中断向量设置

2.串口中断服务函数

3.DMA中断服务函数

具体实现如下：

一。初始化

1 //串口1的初始化2 //bound:波特率
3 /************************************************/
4 void uart1_init(u32 bound)
5 {
6     GPIO_InitTypeDef GPIO_InitStructure;
7     USART_InitTypeDef USART_InitStructure;
8     NVIC_InitTypeDef NVIC_InitStructure;
9     DMA_InitTypeDef DMA_InitStructure;

1。IO时钟+串口时钟+DMA时钟使能。

RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA, ENABLE);    //串口1时钟初始化+GPIOA时钟初始化

RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1,ENABLE); 　　//DMA1初始化

2.IO初始化

 1     USART_DeInit(USART1);  //¸´Î»´®¿Ú1
 2     //USART1_TX   PA.9
 3   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; //PA.9
 4   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
 5   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;    //¸´ÓÃÍÆÍìÊä³ö
 6   GPIO_Init(GPIOA, &GPIO_InitStructure); //³õʼ»¯PA9
 7   //USART1_RX      PA.10
 8   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
 9   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//¸¡¿ÕÊäÈë
10   GPIO_Init(GPIOA, &GPIO_InitStructure);  //³õʼ»¯PA10

3.串口初始化

 1     USART_InitStructure.USART_BaudRate = bound;//Ò»°ãÉèÖÃΪ9600;
 2     USART_InitStructure.USART_WordLength = USART_WordLength_8b;//×Ö³¤Îª8λÊý¾Ý¸ñʽ
 3     USART_InitStructure.USART_StopBits = USART_StopBits_1;//Ò»¸öֹͣλ
 4     USART_InitStructure.USART_Parity = USART_Parity_No;//ÎÞÆæżУÑéλ
 5     USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//ÎÞÓ²¼þÊý¾ÝÁ÷¿ØÖÆ
 6     USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;    //ÊÕ·¢Ä£Ê½
 7   USART_Init(USART1, &USART_InitStructure); //³õʼ»¯´®¿
 8
 9     USART_ITConfig(USART1, USART_IT_IDLE , ENABLE);//¿ªÆôÖжÏ
10     USART_DMACmd(USART1,USART_DMAReq_Tx,ENABLE);//串口发送DMA使能
11     USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);//串口接收DMA使能
12   USART_Cmd(USART1, ENABLE);//ʹÄÜ´®¿Ú
13     USART_ClearFlag(USART1,USART_FLAG_TC);//Çå³ý·¢ËÍÍê³É±êÖ¾

4。DMA初始化

 1 //DMA1_Channel5 -> USART1_Rx
 2     DMA_Cmd(DMA1_Channel5,DISABLE);
 3     DMA_DeInit(DMA1_Channel5);
 4     DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&USART1->DR);//ÍâÉèΪUSART2->DR
 5     DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)USART1_Receive_Data;//ÄÚ´æ»ùµØÖ·
 6     DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;//ÍâÉè×÷ΪÊý¾Ý´«ÊäµÄÄ¿µÄµØ£¬½ÓÊÕ
 7     DMA_InitStructure.DMA_BufferSize = 1024;//ÄÚ´æ´óС
 8     DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//ÍâÉèµØÖ·¼Ä´æÆ÷²»±ä
 9     DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//ÄÚ´æµØÖ·¼Ä´æÆ÷µÝÔö
10     DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//Êý¾Ý¿í¶ÈΪ8λ
11     DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//Êý¾Ý¿í¶ÈΪ8λ
12     DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;//¹¤×÷ÔÚÕý³£»º´æģʽ
13     DMA_InitStructure.DMA_Priority = DMA_Priority_High;//DMAͨµÀ5¾ßÓиßÓÅÏȼ¶
14     DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;//DMAͨµÀ6ûÓÐÉèÖÃΪÄÚ´æµ½ÄÚ´æ´«Êä
15     DMA_Init(DMA1_Channel5,&DMA_InitStructure);
16     DMA_ITConfig(DMA1_Channel5,DMA_IT_TC,ENABLE);//ʹÄÜ´«ÊäÍê³ÉÖжÏ
17     DMA_Cmd(DMA1_Channel5,ENABLE);
18     //DMA1_Channel4 -> USART1_Tx
19     DMA_Cmd(DMA1_Channel4,DISABLE);
20     DMA_DeInit(DMA1_Channel4);
21     DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&USART1->DR);//ÍâÉèΪUSART2->DR
22     DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)USART_Send.USART1_Send_Data;//ÄÚ´æ»ùµØÖ·
23     DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;//ÍâÉè×÷ΪÊý¾Ý´«ÊäµÄÀ´Ô´£¬·¢ËÍ
24     DMA_InitStructure.DMA_BufferSize = 1024;//ÄÚ´æ´óС
25     DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//ÍâÉèµØÖ·¼Ä´æÆ÷²»±ä
26     DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//ÄÚ´æµØÖ·¼Ä´æÆ÷µÝÔö
27     DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//Êý¾Ý¿í¶ÈΪ8λ
28     DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//Êý¾Ý¿í¶ÈΪ8λ
29     DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;//¹¤×÷ÔÚÕý³£»º´æģʽ
30     DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;//DMAͨµÀ5¾ßÓиßÓÅÏȼ¶
31     DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;//DMAͨµÀ6ûÓÐÉèÖÃΪÄÚ´æµ½ÄÚ´æ´«Êä
32     DMA_Init(DMA1_Channel4,&DMA_InitStructure);
33     DMA_ITConfig(DMA1_Channel4,DMA_IT_TC,ENABLE);//ʹÄÜ´«ÊäÍê³ÉÖжÏ
34     DMA_Cmd(DMA1_Channel4,ENABLE);

5.中断向量设置

 1     //USART1_NVIC
 2   NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
 3     NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0 ;//ÇÀÕ¼ÓÅÏȼ¶1
 4     NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;        //×ÓÓÅÏȼ¶0
 5     NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;            //IRQͨµÀʹÄÜ
 6     NVIC_Init(&NVIC_InitStructure);    //¸ù¾ÝÖ¸¶¨µÄ²ÎÊý³õʼ»¯VIC¼Ä´æÆ
 7     //DMA_Channel5 NVIC -> USART1_Rx
 8     NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel5_IRQn;
 9     NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
10     NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
11     NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
12     NVIC_Init(&NVIC_InitStructure);
13     //DMA_Channel4 NVIC -> USART1_Tx
14     NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel4_IRQn;
15     NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
16     NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
17     NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
18     NVIC_Init(&NVIC_InitStructure);

}

//以上的话，初始化就完成了~~~~~，下面是USART中断服务函数

二。串口中断函数

 1 #if EN_USART1_RX   //Èç¹ûʹÄÜÁ˽ÓÊÕ
 2 void USART1_IRQHandler(void)                    //´®¿Ú1ÖжϷþÎñ³ÌÐò
 3 {
 4     u16 DATA_LEN;
 5     u16 i = 0;
 6     u8 Res;
 7     if(USART_GetITStatus(USART1, USART_IT_IDLE ) != RESET)  //¿ÕÏÐÖжÏ
 8     {
 9         Res = USART1->SR;
10         Res = USART1->DR;//Çå³ý¿ÕÏÐÖжϱêÖ¾
11
12         DMA_Cmd(DMA1_Channel5,DISABLE);//¹Ø±ÕDMA,·ÀÖ¹´¦ÀíÆä¼äÓÐÊý¾Ý
13         DATA_LEN = 1024 - DMA_GetCurrDataCounter(DMA1_Channel5);//»ñÈ¡Êý¾Ý³¤¶È
14         //±£´æ½ÓÊÕµ½µÄÊý¾Ý,·ÅÖõ½USART2_SendData
15         USART_Send.USART1_Len_R = DATA_LEN; //±£´æÊý¾Ý³¤¶È
16         for(i=0;i<DATA_LEN;i++)
17         {
18             USART_Send.USART1_Receive_Data[i] = USART1_Receive_Data[i];//±£´æÊý¾Ý
19         }
20         USART_Send.USART1_Rx_Finish = 1;//±êÖ¾ÖÃ1£¬±íʾÊý¾Ý±£´æÍê±Ï
21
22         DMA1_Channel5->CNDTR = 1024;//ÖØÐÂÉèÖÃDMA1_Channel5µÄÊý¾Ý´«ÊäÊýÁ¿
23         DMA_Cmd(DMA1_Channel5,ENABLE);//¿ªÆôDMA1_Channel5
24     }
25
26 } 

三。DMA通道中断服务函数

//DMA1_Channel5-RxÖжϷþÎñº¯Êý,usart1_Rx
void DMA1_Channel5_IRQHandler(void)
{
    DMA_ClearITPendingBit(DMA1_IT_TE5);//Çå³ý´íÎóÖжÏ
    if(DMA_GetITStatus(DMA1_IT_TC5))//·¢ÉúÁË´«ÊäÍê³ÉÖжÏ
    {
        u16 DATA_LEN;
        u16 i = 0;
        u8 Res;
        DMA_ClearITPendingBit(DMA1_IT_TC5);//Çå³ýÖжÏÍê³É±êÖ¾
        DMA_Cmd(DMA1_Channel5,DISABLE);//¹Ø±ÕDMA,·ÀÖ¹´¦ÀíÆÚ¼äÓÐÊý¾Ý

        DATA_LEN = 1024 - DMA_GetCurrDataCounter(DMA1_Channel5);//»ñÈ¡Êý¾Ý³¤¶È
        //±£´æ½ÓÊÕµ½µÄÊý¾Ý,·ÅÖõ½USART2_SendData
        USART_Send.USART1_Len_R = DATA_LEN; //±£´æÊý¾Ý³¤¶È
        for(i=0;i<DATA_LEN;i++)
        {
            USART_Send.USART1_Receive_Data[i] = USART1_Receive_Data[i];//±£´æÊý¾Ý
        }
        USART_Send.USART1_Rx_Finish = 1;//±êÖ¾ÖÃ1£¬±íʾÊý¾Ý±£´æÍê±Ï

        DMA1_Channel5->CNDTR = 1024;//ÖØÐÂÌî×°
        DMA_Cmd(DMA1_Channel5,ENABLE);//´¦ÀíÍê³Éºó£¬ÖØ¿ªDMA
    }
}

//DMA1_Channel4-TxÖжϷþÎñº¯Êý,usart1_Tx
void DMA1_Channel4_IRQHandler(void)
{
    DMA_ClearITPendingBit(DMA1_IT_TE4);//Çå³ý´íÎóÖжϱêÖ¾
    if(DMA_GetITStatus(DMA1_IT_TC4))//·¢Éú´«ÊäÍê³ÉÖжϱêÖ¾
    {
        DMA_ClearITPendingBit(DMA1_IT_TC4);//Çå³ýÖжϱêÖ¾
        DMA_Cmd(DMA1_Channel4,DISABLE);//¹Ø±ÕÖжÏ
        USART_Send.USART1_Tx_Finish = 0;
    }
}

很困，别的+注释这周补上。。。