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[导读]使用DMA操作UART4:一、DMA映射表见下表:UART4的发送 UART4_TX 在Stream4。UART4的接收 UART4_RX在Stream2。他们在Channel_4。二、程序代码unsigned char btDMARecbuf[255];// DMA接收数据地址unsigned char btDMAS

使用DMA操作UART4:

一、DMA映射表

见下表:

UART4的发送 UART4_TX 在Stream4。

UART4的接收 UART4_RX在Stream2。

他们在Channel_4。

二、程序代码

unsigned char btDMARecbuf[255];// DMA接收数据地址

unsigned char btDMASendbuf[255];//DMA发送数据地址


// 初始化

void UartDMA()

{

//定义中断结构体

NVIC_InitTypeDef NVIC_InitStructure ;

//定义IO初始化结构体

GPIO_InitTypeDef GPIO_InitStructure;

//定义串口结构体

USART_InitTypeDef USART_InitStructure;

//定义DMA结构体

DMA_InitTypeDef DMA_InitStructure;


USART_DeInit(UART4); // 串口4

DMA_DeInit(DMA1_Stream2); // 接收

DMA_DeInit(DMA1_Stream4); // 发送


//设置IO口时钟

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);

GPIO_PinAFConfig(GPIOC,GPIO_PinSource10,GPIO_AF_UART4);

GPIO_PinAFConfig(GPIOC,GPIO_PinSource11,GPIO_AF_UART4);


//管脚模式:输出口

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

//类型:推挽模式

GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

//上拉下拉设置

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

//IO口速度

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

//管脚指定

GPIO_InitStructure.GPIO_Pin =GPIO_Pin_10;

//初始化

GPIO_Init(GPIOC, &GPIO_InitStructure);


//管脚模式:输入口

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

//上拉下拉设置

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;

//管脚指定

GPIO_InitStructure.GPIO_Pin =GPIO_Pin_11;

//初始化

GPIO_Init(GPIOC, &GPIO_InitStructure);


//打开串口对应的外设时钟

RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART4, ENABLE);


//串口发 - DMA配置

//启动DMA时钟

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);

//DMA发送中断设置

NVIC_InitStructure.NVIC_IRQChannel = DMA1_Stream4_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);


//DMA通道配置

DMA_InitStructure.DMA_Channel = DMA_Channel_4;

//外设地址

DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)(&UART4->DR);

//内存地址

DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)btDMASendbuf;

//dma传输方向

DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;

//设置DMA在传输时缓冲区的长度

DMA_InitStructure.DMA_BufferSize = 255;

//设置DMA的外设递增模式,一个外设

DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;

//设置DMA的内存递增模式

DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;

//外设数据字长

DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;

//内存数据字长

DMA_InitStructure.DMA_MemoryDataSize = DMA_PeripheralDataSize_Byte;

//设置DMA的传输模式

DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;

//设置DMA的优先级别

DMA_InitStructure.DMA_Priority = DMA_Priority_High;


//指定如果FIFO模式或直接模式将用于指定的流 : 不使能FIFO模式

DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;

//指定了FIFO阈值水平

DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;

//指定的Burst转移配置内存传输

DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;

//指定的Burst转移配置外围转移 */

DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;


//配置DMA1的通道

DMA_Init(DMA1_Stream4, &DMA_InitStructure);

//使能中断

DMA_ITConfig(DMA1_Stream4, DMA_IT_TC, ENABLE);


//串口收 - DMA配置

DMA_InitStructure.DMA_Channel = DMA_Channel_4;

//外设地址

DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)(&UART4->DR);

//内存地址

DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)btDMARecbuf;

//dma传输方向

DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;

//设置DMA在传输时缓冲区的长度

DMA_InitStructure.DMA_BufferSize = 255;

//设置DMA的外设递增模式,一个外设

DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;

//设置DMA的内存递增模式

DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;

//外设数据字长

DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;

//内存数据字长

DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;

//设置DMA的传输模式

DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;

//设置DMA的优先级别

DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;


//指定如果FIFO模式或直接模式将用于指定的流 : 不使能FIFO模式

DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;

//指定了FIFO阈值水平

DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;

//指定的Burst转移配置内存传输

DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;

//指定的Burst转移配置外围转移 */

DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;


//配置DMA1的通道

DMA_Init(DMA1_Stream2, &DMA_InitStructure);

//使能通道

DMA_Cmd(DMA1_Stream2, ENABLE);


//初始化串口参数

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_InitStructure.USART_BaudRate = 115200;

//初始化串口

USART_Init(UART4, &USART_InitStructure);


//配置中断

NVIC_InitStructure.NVIC_IRQChannel = UART4_IRQn; //通道设置为串口中断

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; //中断占先等级

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; //中断响应优先级

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //打开中断

NVIC_Init(&NVIC_InitStructure);


//采用DMA方式发送

USART_DMACmd(UART4, USART_DMAReq_Tx, ENABLE);

//采用DMA方式接收

USART_DMACmd(UART4, USART_DMAReq_Rx, ENABLE);


//中断配置

USART_ITConfig(UART4, USART_IT_TC, DISABLE);

USART_ITConfig(UART4, USART_IT_RXNE, DISABLE);

USART_ITConfig(UART4, USART_IT_TXE, DISABLE);

USART_ITConfig(UART4, USART_IT_IDLE, ENABLE);


USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);

USART_ITConfig(UART4, USART_IT_PE, ENABLE); //开启PE错误接收中断Bit 8PEIE: PE interrupt enable

USART_ITConfig(UART4, USART_IT_ERR, ENABLE);//CR2 开启ERR中断


//启动串口

USART_Cmd(UART4, ENABLE);


while(!DMA_GetCmdStatus(DMA1_Stream4))

{

DMA_Cmd(DMA1_Stream4, ENABLE);

}


while(!DMA_GetCmdStatus(DMA1_Stream2))

{

DMA_Cmd(DMA1_Stream2, ENABLE);

}

}


// 发送

void UartSend(uint8_t *data, uint8_t size)

{

unsigned char i;

//复制数据

for (i=0; i

{

btDMASendbuf[i] = data[i];

}

//设置传输数据长度

DMA_SetCurrDataCounter(DMA1_Stream4, size);

//打开DMA, 开始发送

DMA_Cmd(DMA1_Stream4, ENABLE);

}

// DMA发送中断处理函数

void DMA1_Stream4_IRQHandler(void)

{

if(DMA_GetITStatus(DMA1_Stream4, DMA_IT_TCIF4) != RESET)

{

//清除标志位

DMA_ClearFlag(DMA1_Stream4, DMA_FLAG_TCIF4);

//关闭DMA

DMA_Cmd(DMA1_Stream4, DISABLE);

//打开发送完成中断, 发送最后两个字节

USART_ITConfig(UART4, USART_IT_TC, ENABLE);

}

}

// 串口中断处理函数

void UART4_IRQHandler(void)

{

unsigned char i;

unsigned char len = 0;

//发送完成中断处理

if(USART_GetITStatus(UART4, USART_IT_TC) != RESET)

{

//关闭发送完成中断

USART_ITConfig(UART4, USART_IT_TC, DISABLE);

}

//接

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