STM32的串口采用DMA方式接收数据测试-RoboMaster 社区

STM32的串口采用DMA方式接收数据测试

767

2015-03-04

STM32的串口采用DMA方式接收数据测试

本文博客链接:http://blog.csdn.net/jdh99,作者:jdh,转载请注明.

参考链接:http://www.amobbs.com/forum.php? ... a%E6%8E%A5%E6%94%B6

环境：

主机:WINXP

开发环境:MDK4.23

MCU:STM32F103CBT6

说明:

串口可以配置成用DMA的方式接收数据,不过DMA需要定长才能产生接收中断,如何接收可变长度的数据呢?

方法有以下3种:

1.将RX脚与一路时钟外部引脚相连,当串口一帧发完,即可利用此定时器产生超时中断.这个实时性较高,可以做到1个字节实时监测.

2.不改变硬件,开启一个定时器监控DMA接收,如果超时则产生中断.这个实时性不高,因为超时时间必须要大于需要接收帧的时间,精度不好控制.

3.STM32单片机有的串口可以监测总线是否处于空闲,如果空闲则产生中断.可以用它来监测DMA接收是否完毕.这种方式实时性很高.

本文采用第3种方式.在波特率576000下大数据包冲击证明可行.

源代码:

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//串口接收DMA缓存
#define UART_RX_LEN 128
extern uint8_t Uart_Rx[UART_RX_LEN];

[cpp] view plaincopy

//串口接收DMA缓存
uint8_t Uart_Rx[UART_RX_LEN] = {0};

[cpp] view plaincopy

//---------------------串口功能配置---------------------
//打开串口对应的外设时钟
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 , ENABLE);
//串口发DMA配置
//启动DMA时钟
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
//DMA发送中断设置
NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel4_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
//DMA1通道4配置
DMA_DeInit(DMA1_Channel4);
//外设地址
DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&USART1->DR);
//内存地址
DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)Uart_Send_Buffer;
//dma传输方向单向
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
//设置DMA在传输时缓冲区的长度
DMA_InitStructure.DMA_BufferSize = 100;
//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;
//设置DMA的2个memory中的变量互相访问
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
DMA_Init(DMA1_Channel4,&DMA_InitStructure);
DMA_ITConfig(DMA1_Channel4,DMA_IT_TC,ENABLE);
//使能通道4
//DMA_Cmd(DMA1_Channel4, ENABLE);
//串口收DMA配置
//启动DMA时钟
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
//DMA1通道5配置
DMA_DeInit(DMA1_Channel5);
//外设地址
DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&USART1->DR);
//内存地址
DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)Uart_Rx;
//dma传输方向单向
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
//设置DMA在传输时缓冲区的长度
DMA_InitStructure.DMA_BufferSize = UART_RX_LEN;
//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;
//设置DMA的2个memory中的变量互相访问
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
DMA_Init(DMA1_Channel5,&DMA_InitStructure);
//使能通道5
DMA_Cmd(DMA1_Channel5,ENABLE);
//初始化参数
//USART_InitStructure.USART_BaudRate = DEFAULT_BAUD;
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 = DEFAULT_BAUD;
//初始化串口
USART_Init(USART1,&USART_InitStructure);
//TXE发送中断,TC传输完成中断,RXNE接收中断,PE奇偶错误中断,可以是多个
//USART_ITConfig(USART1,USART_IT_RXNE,ENABLE);
//中断配置
USART_ITConfig(USART1,USART_IT_TC,DISABLE);
USART_ITConfig(USART1,USART_IT_RXNE,DISABLE);
USART_ITConfig(USART1,USART_IT_IDLE,ENABLE);
//配置UART1中断
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3);
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn; //通道设置为串口1中断
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; //中断占先等级0
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; //中断响应优先级0
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //打开中断
NVIC_Init(&NVIC_InitStructure);
//采用DMA方式发送
USART_DMACmd(USART1,USART_DMAReq_Tx,ENABLE);
//采用DMA方式接收
USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);
//启动串口
USART_Cmd(USART1, ENABLE);

[cpp] view plaincopy

//串口1接收中断
void USART1_IRQHandler(void)
{
uint32_t temp = 0;
uint16_t i = 0;
if(USART_GetITStatus(USART1, USART_IT_IDLE) != RESET)
{
//USART_ClearFlag(USART1,USART_IT_IDLE);
temp = USART1->SR;
temp = USART1->DR; //清USART_IT_IDLE标志
DMA_Cmd(DMA1_Channel5,DISABLE);
temp = UART_RX_LEN - DMA_GetCurrDataCounter(DMA1_Channel5);
for (i = 0;i < temp;i++)
{
Data_Receive_Usart = Uart_Rx;
//启动串口状态机
usart_state_run();
}
//设置传输数据长度
DMA_SetCurrDataCounter(DMA1_Channel5,UART_RX_LEN);
//打开DMA
DMA_Cmd(DMA1_Channel5,ENABLE);
}
__nop();
}

测试结果:
条件:单片机运行于72M,与PC通信速率为460800.PC每隔100ms发送一个9个字节的包:c5 5c 6 0 6F 10 5 4e f7.
测试:单片机每次收到此包,一个IO作电平跳转,然后处理返回一包.
示波器显示:

放大显示:

本文博客链接:http://blog.csdn.net/jdh99,作者:jdh,转载请注明

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STM32的串口采用DMA方式接收数据测试