STM32F103RCT6+串口DMA方式接收定长数据

1.接收缓存数组初始化

#define USART_REC_LEN  100  //定义最大字节数 100

u8 USART_RX_BUF[USART_REC_LEN];     //接收缓冲,最大USART_REC_LEN个字节.

2.串口初始化

void uart_init(u32 bound)

{

  //GPIO端口设置

    GPIO_InitTypeDef GPIO_InitStructure;

USART_InitTypeDef USART_InitStructure;

NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA, ENABLE);//使能

    USART1，GPIOA时钟

//USART1_TX   GPIOA.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GPIOA.9

  //USART1_RX  GPIOA.10初始化

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;//PA10

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//浮空输入

  GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIOA.10  

  //Usart1 NVIC 配置

    NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ;//抢占优先级3

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;//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

   //USART 初始化设置

USART_InitStructure.USART_BaudRate = bound;//串口波特率

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1

 // USART_ITConfig(USART1, USART_IT_IDLE, ENABLE);//开启串口接受中断

USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);//使能DMA接收

  USART_Cmd(USART1, ENABLE);                    //使能串口1 

}

3.DMA配置

void Usart1_DMA_init()

{

    DMA_InitTypeDef DMA_InitStructure;

  NVIC_InitTypeDef NVIC_InitStructure;

  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); //DMA1 时钟使能

  DMA_DeInit(DMA1_Channel5);//将DMA的通道5寄存器重设为缺省值  串口1对应的是DMA通道5(接收)

  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&USART1->DR;//DMA外设UASRT1->DR基地址

    DMA_InitStructure.DMA_MemoryBaseAddr = (u32)USART_RX_BUF;//DMA内存基地址

    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;//DMA方向  外设->内存

    DMA_InitStructure.DMA_BufferSize = sizeof(USART_RX_BUF);//DMA通道的DMA缓存的大小

    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外设地址不增加

    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//内存地址自增1

    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//数据宽度为8位

    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//数据宽度为8位

    DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;

    //DMA_Mode_Normal（只传送一次）, DMA_Mode_Circular （不停地传送）

    DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;//(DMA传送优先级为中等)

    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;//DMA通道x没有设置为内存到内存传输

    DMA_Init(DMA1_Channel5, &DMA_InitStructure);//初始化DMA1 通道5

    DMA_Cmd(DMA1_Channel5, ENABLE);  //启动DMA传输

  //DMA发送中断配置

  NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel5_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;//抢占优先级3

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;//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_ITConfig(DMA1_Channel5, DMA_IT_TC, ENABLE);//使能DMA传输完成中断

}

 4.DMA中断服务程序

void DMA1_Channel5_IRQHandler(void)

{

if(DMA_GetFlagStatus(DMA1_FLAG_TC5)==SET)

   {

        DMA_ClearFlag(DMA1_FLAG_TC5);//清中断标志，否则会一直中断

  printf("进入DMA发送中断！\r\n");       

   }

}

可见，串口每接收100个字节产生一次DMA中断！