2019年01月07日 | stm32f103串口dma配置实例

1. 串口配置

void USART3_Configuration(uint32_t Baudrate)

{

GPIO_InitTypeDef GPIO_InitStructure;

USART_InitTypeDef USART_InitStructure;

NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3,ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);

GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;

GPIO_InitStructure.GPIO_Pin=GPIO_Pin_10;

GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;

GPIO_Init(GPIOB,&GPIO_InitStructure);

GPIO_InitStructure.GPIO_Mode=GPIO_Mode_IN_FLOATING;

GPIO_InitStructure.GPIO_Pin=GPIO_Pin_11;

GPIO_Init(GPIOB,&GPIO_InitStructure);

USART_InitStructure.USART_BaudRate=Baudrate;

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_Init(USART3,&USART_InitStructure);

USART_ITConfig(USART3, USART_IT_IDLE,ENABLE);

USART_Cmd(USART3,ENABLE);

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure); 

}

2.DMA配置

void DMA_USART3Rx_Init(void)

{

RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

DMA_DeInit(DMA1_Channel3);

DMA_InitStructure.DMA_PeripheralBaseAddr=(u32)&USART3->DR;

DMA_InitStructure.DMA_MemoryBaseAddr=(u32)USART3_DMA_Rxbuf;

DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;

DMA_InitStructure.DMA_BufferSize=DMA1_MEM_LEN;

DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;

DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;

DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;

DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;

DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;  

DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;

DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;

DMA_Init(DMA1_Channel3,&DMA_InitStructure);  

DMA_Cmd(DMA1_Channel3,ENABLE);

USART_DMACmd(USART3,USART_DMAReq_Rx,ENABLE);

}

3.串口中断处理

void USART3_IRQHandler(void)

{

int temp = 0;

unsigned int i=0;

if(USART_GetITStatus(USART3,USART_IT_IDLE)!=RESET)

{

temp = USART3->SR;

temp = USART3->DR;

DMA_Cmd(DMA1_Channel3,DISABLE); 

temp=DMA_GetCurrDataCounter(DMA1_Channel3);

Rx_Len=USART_BUF_MAX-DMA_GetCurrDataCounter(DMA1_Channel3);

if(Rx_Len>=USART_BUF_MAX)

{

}

else

{

if(USART_data_flag==0)

{

for(i=0;i

DMA_Rxbuf[i]=USART3_DMA_Rxbuf[i];

DMA_Rxbuf[i]='\0';

}

USART_EOF=1;

}

DMA_SetCurrDataCounter(DMA1_Channel3,USART_BUF_MAX); 

DMA_Cmd(DMA1_Channel3,ENABLE);

temp=temp;

}

}

备注：在此串口接收函数中 如果接收的数据大于接收buffer 则会出错 需要防止这种错误