STM32关于USART3 DMA使用

DMA,即直接内存存储,在一些数据的传输中,采用DMA方式,从而将CPU解放出来。

STM32关于USART3 DMA使用_第1张图片

USART3使用DMA 通道3。

usart3配置

	
     UART3   RX3--->PB.11   TX3 --->PB.10 
 
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
	
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB , ENABLE); //使能UART3所在GPIOB的时钟
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3,ENABLE); //串口时钟配置	 


GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_11;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;          
GPIO_Init(GPIOB, &GPIO_InitStructure);	

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;				            
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; 	       	  //推挽输出   ULTR_EN-->PB.10
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;		        //IO口速度为50MHz
GPIO_Init(GPIOB, &GPIO_InitStructure);					            //根据设定参数初始化PB.10

USART_InitStructure.USART_BaudRate = 9600;
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;	//收发模式
USART_Init(USART3, &USART_InitStructure);

//Usart3 NVIC 配置
NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;//抢占优先级2
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;		//子优先级0
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_ITConfig(USART3,USART_IT_TC,DISABLE);  //关闭发送中断 
USART_ITConfig(USART3,USART_IT_RXNE,DISABLE);//关闭接收中断  
USART_ITConfig(USART3,USART_IT_IDLE,ENABLE); //开启总线空闲中断 
USART_Cmd(USART3, ENABLE);	      // 使能 USART3

DMA配置

DMA_InitTypeDef DMA_InitStructure;	
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);                      //使能DMA1时钟  
DMA_DeInit(DMA1_Channel3);                                              //初始化DMA1通道3  串口3接收通道
DMA_InitStructure.DMA_PeripheralBaseAddr = 0x40004804;                  //串口3接收数据的地址
DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)GPS_Uart_Rcv_Buf;      //数据存放的复制
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;                      //数据传送方向  串口3作为数据源
DMA_InitStructure.DMA_BufferSize = GPS_Rev_Buf_Size;                    //接收数据个数       
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;        //外围设备 串口3 地址不递增
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;                 // DMA存储地址递增
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte; //外围设备 串口3 数据宽度 8bits
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;         //DMA存储 数据宽度 8bits
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;                         //循环获取数据
//DMA_Mode_Normal(只传送一次), DMA_Mode_Circular (不停地传送)
DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;                   //串口3通道优先为中等
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;                            //关闭内存到内存
DMA_Init(DMA1_Channel3, &DMA_InitStructure);


USART_DMACmd(USART3, USART_DMAReq_Rx, ENABLE);  //使能串口3 DMA功能
DMA_Cmd(DMA1_Channel3, ENABLE);

USART3中断


/*--------------
DMA接收一次数据后停止工作并触发进入串口总线中断
-------------*/
//DMA mode 设置为DMA_Mode_Normal
//DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;                         //接收一次DMA数据停止工作
//DMA_Mode_Normal(只传送一次), DMA_Mode_Circular (不停地传送)
void USART3_IRQHandler(void)                	
{
	u8 i = 0;	
	if(USART_GetITStatus(USART3, USART_IT_IDLE) != RESET)		//串口3	总线空闲	
	{
    	USART_ClearITPendingBit(USART3, USART_IT_IDLE);  //清除标记位					
		if(GPS_Uart_Rcv_Buf[0]!= '$') //出错
		{
			i = 0;
		}
		else//完成获取数据
		{
			i = 0;	
			//标记
		}
	}
	
}
/*------------------
DMA连续接收数据并持续触发串口总线中断
-----------------*/
//DMA mode 设置为DMA_Mode_Circular
//DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;                         //循环获取数据
void USART3_IRQHandler(void)                	
{
	u8 i = 0;	
	if(USART_GetITStatus(USART3, USART_IT_IDLE) != RESET)		//串口3	总线空闲	
	{
  	    USART_ClearITPendingBit(USART3, USART_IT_IDLE);  //清除标记位			
		if(GPS_Uart_Rcv_Buf[0]!= '$') //出错
		{
			i = 0;
		}
		else//完成获取数据
		{
			i = 0;	
			//标记
		}
	}
	
}
/*------------------
DMA连续接收数据并持续触发串口总线中断。在接收一次后关闭DMA功能
-----------------*/
//DMA mode 设置为DMA_Mode_Circular
//DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;                         //循环获取数据
void USART3_IRQHandler(void)                	
{
	u8 i = 0;	
	if(USART_GetITStatus(USART3, USART_IT_IDLE) != RESET)		//串口3	总线空闲	
	{
  	    USART_ClearITPendingBit(USART3, USART_IT_IDLE);  //清除标记位	
/*----------------------------------------------------------*/		
		DMA_Cmd(DMA1_Channel3, DISABLE);//关闭DMA1通道3
/*----------------------------------------------------------*/
		if(GPS_Uart_Rcv_Buf[0]!= '$') //出错
		{
			i = 0;
		}
		else//完成获取数据
		{
			i = 0;	
			//标记
		}
	}
	
}
/*------------------
DMA连续接收数据并持续触发串口总线中断。人为控制DMA接收频率
-----------------*/
//DMA mode 设置为DMA_Mode_Circular
//DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;                         //循环获取数据
void USART3_IRQHandler(void)                	
{
	u8 i = 0;	
	if(USART_GetITStatus(USART3, USART_IT_IDLE) != RESET)		//串口3	总线空闲	
	{
  	USART_ClearITPendingBit(USART3, USART_IT_IDLE);  //清除标记位			
		DMA_Cmd(DMA1_Channel3, DISABLE);//关闭DMA1通道3
		if(GPS_Uart_Rcv_Buf[0]!= '$') //出错
		{
			i = 0;
		}
		else//完成获取数据
		{
			i = 0;	
			//标记
		}
		DMA_SetCurrDataCounter(DMA1_Channel3,GPS_Rev_Buf_Size);  //接收数据个数  
		DMA_Cmd(DMA1_Channel3, ENABLE);                          //开启DMA1通道3	
	}	
}

 

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