STM32F4 串口DMA接收
STM32F4 串口DMA接收需要注意的点:
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory; //存储器到外设模式 RX TX不同这里,外设到地址或者地址到外设
这句代码跟发射的不一样。
我这里用的是串口2,PA2 PA3
GPIO配置如下:
void uart_init(u32 bound)
{
//GPIO端口设置
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE); //使能GPIOA时钟
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2,ENABLE);//使能USART1时钟
//串口1对应引脚复用映射
GPIO_PinAFConfig(GPIOA,GPIO_PinSource2,GPIO_AF_USART2); //GPIOA9复用为USART1
GPIO_PinAFConfig(GPIOA,GPIO_PinSource3,GPIO_AF_USART2); //GPIOA10复用为USART1
//USART1端口配置
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3; //GPIOA9与GPIOA10
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//复用功能
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //速度50MHz
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //推挽复用输出
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //上拉
GPIO_Init(GPIOA,&GPIO_InitStructure); //初始化PA9,PA10
//USART1 初始化设置
USART_InitStructure.USART_BaudRate = bound;//波特率设置
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(USART2, &USART_InitStructure); //初始化串口1
USART_Cmd(USART2, ENABLE);
}
接下来是串口DMA接收模式配置
void DMA_UART_RX(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
DMA_InitTypeDef DMA_InitStructure;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE); //开启DMA时钟
DMA_DeInit(DMA1_Stream5);
while(DMA_GetCmdStatus(DMA1_Stream5) != DISABLE){} //等待stream可配置,即DMAy_SxCR.EN变为0
//配置Stream
DMA_InitStructure.DMA_Channel = DMA_Channel_4; //从8个channel中选择一个
DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&USART2->DR; //外设地址
DMA_InitStructure.DMA_Memory0BaseAddr = (u32)Rx_Buf; //存储器0地址,双缓存模式还要使用M1AR
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory; //存储器到外设模式 RX TX不同这里,外设到地址或者地址到外设
DMA_InitStructure.DMA_BufferSize = RX_BUF_LEN; //数据传输量,以外设数据项为单位
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; //外设地址保持不变
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; //存储器地址递增
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte; //外设数据位宽:8位
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte; //存储器数据位宽:8位
DMA_InitStructure.DMA_Mode = DMA_Mode_Normal; //普通模式(与循环模式对应)
DMA_InitStructure.DMA_Priority = DMA_Priority_Medium; //中等优先级
DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable; //禁止FIFO模式
DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_1QuarterFull;
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single; //单次传输
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single; //单次传输
DMA_Init(DMA1_Stream5, &DMA_InitStructure);
/* 6. 配置DMA中断优先级 */
NVIC_InitStructure.NVIC_IRQChannel = DMA1_Stream5_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
DMA_Cmd(DMA1_Stream5, ENABLE); //开启DMA传输
DMA_ITConfig(DMA1_Stream5,DMA_IT_TC,ENABLE);
//采用DMA方式接收
USART_DMACmd(USART2,USART_DMAReq_Rx,ENABLE);
}
下面是DMA接收完成中断
void DMA1_Stream5_IRQHandler(void)
{
//清除标志
if(DMA_GetFlagStatus(DMA1_Stream5,DMA_FLAG_TCIF5)!=RESET)//等待DMA2_Steam7传输完成
{
DMA_Cmd(DMA1_Stream5, DISABLE); //关闭DMA,防止处理其间有数据
UART2_ReceiveSize = RX_BUF_LEN - DMA_GetCurrDataCounter(DMA1_Stream5);
DMA_ClearFlag(DMA1_Stream5,DMA_FLAG_TCIF5 | DMA_FLAG_FEIF5 | DMA_FLAG_DMEIF5 | DMA_FLAG_TEIF5 | DMA_FLAG_HTIF5);//清除DMA2_Steam7传输完成标志
DMA_SetCurrDataCounter(DMA1_Stream5, RX_BUF_LEN);
DMA_Cmd(DMA1_Stream5, ENABLE); //打开DMA,
}
}
接下来是主函数调用:
uart_init(115200);
DMA_UART_RX();
while(1);
接收到的串口数据会在 DMA_InitStructure.DMA_Memory0BaseAddr = (u32)Rx_Buf;这里出现,即处理时只处理Rx_Buf的数据即可。
STM32F4 串口DMA接收
STM32F4 串口DMA接收需要注意的点:
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory; //存储器到外设模式 RX TX不同这里,外设到地址或者地址到外设
这句代码跟发射的不一样。
我这里用的是串口2,PA2 PA3
GPIO配置如下:
void uart_init(u32 bound)
{
//GPIO端口设置
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE); //使能GPIOA时钟
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2,ENABLE);//使能USART1时钟
//串口1对应引脚复用映射
GPIO_PinAFConfig(GPIOA,GPIO_PinSource2,GPIO_AF_USART2); //GPIOA9复用为USART1
GPIO_PinAFConfig(GPIOA,GPIO_PinSource3,GPIO_AF_USART2); //GPIOA10复用为USART1
//USART1端口配置
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3; //GPIOA9与GPIOA10
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//复用功能
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //速度50MHz
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //推挽复用输出
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //上拉
GPIO_Init(GPIOA,&GPIO_InitStructure); //初始化PA9,PA10
//USART1 初始化设置
USART_InitStructure.USART_BaudRate = bound;//波特率设置
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(USART2, &USART_InitStructure); //初始化串口1
USART_Cmd(USART2, ENABLE);
}
接下来是串口DMA接收模式配置
void DMA_UART_RX(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
DMA_InitTypeDef DMA_InitStructure;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE); //开启DMA时钟
DMA_DeInit(DMA1_Stream5);
while(DMA_GetCmdStatus(DMA1_Stream5) != DISABLE){} //等待stream可配置,即DMAy_SxCR.EN变为0
//配置Stream
DMA_InitStructure.DMA_Channel = DMA_Channel_4; //从8个channel中选择一个
DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&USART2->DR; //外设地址
DMA_InitStructure.DMA_Memory0BaseAddr = (u32)Rx_Buf; //存储器0地址,双缓存模式还要使用M1AR
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory; //存储器到外设模式 RX TX不同这里,外设到地址或者地址到外设
DMA_InitStructure.DMA_BufferSize = RX_BUF_LEN; //数据传输量,以外设数据项为单位
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; //外设地址保持不变
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; //存储器地址递增
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte; //外设数据位宽:8位
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte; //存储器数据位宽:8位
DMA_InitStructure.DMA_Mode = DMA_Mode_Normal; //普通模式(与循环模式对应)
DMA_InitStructure.DMA_Priority = DMA_Priority_Medium; //中等优先级
DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable; //禁止FIFO模式
DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_1QuarterFull;
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single; //单次传输
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single; //单次传输
DMA_Init(DMA1_Stream5, &DMA_InitStructure);
/* 6. 配置DMA中断优先级 */
NVIC_InitStructure.NVIC_IRQChannel = DMA1_Stream5_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
DMA_Cmd(DMA1_Stream5, ENABLE); //开启DMA传输
DMA_ITConfig(DMA1_Stream5,DMA_IT_TC,ENABLE);
//采用DMA方式接收
USART_DMACmd(USART2,USART_DMAReq_Rx,ENABLE);
}
下面是DMA接收完成中断
void DMA1_Stream5_IRQHandler(void)
{
//清除标志
if(DMA_GetFlagStatus(DMA1_Stream5,DMA_FLAG_TCIF5)!=RESET)//等待DMA2_Steam7传输完成
{
DMA_Cmd(DMA1_Stream5, DISABLE); //关闭DMA,防止处理其间有数据
UART2_ReceiveSize = RX_BUF_LEN - DMA_GetCurrDataCounter(DMA1_Stream5);
DMA_ClearFlag(DMA1_Stream5,DMA_FLAG_TCIF5 | DMA_FLAG_FEIF5 | DMA_FLAG_DMEIF5 | DMA_FLAG_TEIF5 | DMA_FLAG_HTIF5);//清除DMA2_Steam7传输完成标志
DMA_SetCurrDataCounter(DMA1_Stream5, RX_BUF_LEN);
DMA_Cmd(DMA1_Stream5, ENABLE); //打开DMA,
}
}
接下来是主函数调用:
uart_init(115200);
DMA_UART_RX();
while(1);
接收到的串口数据会在 DMA_InitStructure.DMA_Memory0BaseAddr = (u32)Rx_Buf;这里出现,即处理时只处理Rx_Buf的数据即可。
举报