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串口2

usart2.h

//STM32F407 zgt6 串口2

#ifndef __USART2_H

#define __USART2_H

#include "sys.h" 

#define USART2_MAX_RECV_LEN 200

#define USART2_MAX_SEND_LEN 200

extern u8 USART2_RX_buf[USART2_MAX_RECV_LEN];

extern u8 USART2_TX_buf[USART2_MAX_SEND_LEN];

extern u16 USART2_RX_STA;       //接收状态标记 

void uart2_init(u32 bound);

#endif

usart2.c

#include "usart2.h"

u8 USART2_RX_buf[USART2_MAX_RECV_LEN];

u8 USART2_TX_buf[USART2_MAX_SEND_LEN];

u16 USART2_RX_STA=0;//接收状态标记

/* 初始化串口过程

1.串口时钟使能

2.设置引脚复用

3.GPIO端口初始化

4.串口参数初始化

5.初始化NVIC并且开启中断2

6.使能串口

*/

//初始化IO 串口2 

//bound:波特率

void uart2_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USART2时钟 

//串口1对应引脚复用映射

GPIO_PinAFConfig(GPIOA,GPIO_PinSource2,GPIO_AF_USART2); //GPIOA2复用为USART2

GPIO_PinAFConfig(GPIOA,GPIO_PinSource3,GPIO_AF_USART2); //GPIOA3复用为USART2

//USART2端口配置

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3; //GPIOA2与GPIOA3

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PA2，PA3

   //USART2 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2

NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;//串口2中断通道

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3;//抢占优先级3 数值越小优先级越高

NVIC_InitStructure.NVIC_IRQChannelSubPriority =3; //子优先级3,响应优先级

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(USART2, USART_IT_RXNE, ENABLE);//开启接收中断

USART_Cmd(USART2, ENABLE);  //使能串口2

}

void USART2_IRQHandler(void)

{

u8 Res;

if(USART_GetITStatus(USART2, USART_IT_RXNE) != RESET)  //接收中断(接收到的数据必须是0x0d 0x0a结尾)

{

Res =USART_ReceiveData(USART2);//(USART2->DR); //读取接收到的数据

USART_SendData(USART2,Res);//将收到的发回去了

  } 

}

main.c

#include "sys.h"

#include "delay.h"

//#include "usart1.h"

#include "usart2.h"

#include "led.h"

int main(void)

{ 

u8 t=0,len=0;

u16 times=0;

char str[]={'u','1','w','a','i','t','r','n'};

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

delay_init(168);//168 MHz 

LED_Init();

LED1=0;//位带操作点灯 sys.h 

uart2_init(115200);

while(1)

{

if (USART2_RX_STA&0x8000)//接收完成

{

len=USART2_RX_STA&0x3fff;//长度不能超255,因为len是u8

for(t=0;t

{

USART2->DR=USART2_RX_buf[t];

while((USART2->SR & 0x40)==0);//等待发送结束

USART2_RX_STA=0;

}

}

else

{

times++;

if(times %500==0)//5sec

{

for(t=0;t

{

USART2->DR=str[t];

while((USART2->SR & 0x40)==0);//等待发送结束

}

LED1=!LED1;

}

delay_ms(10);

}

}

}

以上必须在模板工程的配置情况下才能运行,本人验证以上代码ok