STM32F103通过串口USART控制LED亮灭

本人使用的是正点原子购买的开发板——精英版STM32F103ZET6
这款开发板的其中一个LED引脚PB5，看下图

#代码直接放在main.c中编译，加入所需库函数
#include <stm32f10x.h>
#include <stm32f10x_usart.h>
#include <stm32f10x_gpio.h>
#include <stm32f10x_rcc.h>
#include <misc.h>
#include <string.h>
#include <stdio.h>
 
//LED开关
#define LED_ON GPIO_ResetBits(GPIOB,GPIO_Pin_5);
#define LED_OFF GPIO_SetBits(GPIOB,GPIO_Pin_5);
 
#define MAX 100     //最长的接收和发送数据大小
u8 RxBuffer[MAX];   //接收寄存数组
u8 TxBuffer[MAX];   //发送寄存数组
 
int RxCount=0;     //接收发送字节数
int TxCount=0;
 
 
//LED的GPIO初始化，此处可以增加替换自己开发板的IO口
void GPIO_LED_init()
{
	GPIO_InitTypeDef GPIO_InitStructure;
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);
	
	GPIO_InitStructure.GPIO_Mode=GPIO_Mode_Out_PP;
	GPIO_InitStructure.GPIO_Pin=GPIO_Pin_5;
	GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
	GPIO_Init(GPIOB,&GPIO_InitStructure);
	
	GPIO_SetBits(GPIOB,GPIO_Pin_5);            //默认关闭LED
}
 
//串口GPIO的初始化 GPIOA_PIN_9为TX，GPIOA_PIN_10为RX
void GPIO_USART_int()
{
	GPIO_InitTypeDef GPIO_InitStructure;
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);
	
	GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;    //TX为复用推挽输出模式
	GPIO_InitStructure.GPIO_Pin=GPIO_Pin_9;
	GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
	GPIO_Init(GPIOA,&GPIO_InitStructure);
	
	GPIO_InitStructure.GPIO_Mode=GPIO_Mode_IN_FLOATING;   //RX为输入悬空模式
	GPIO_InitStructure.GPIO_Pin=GPIO_Pin_10;
	GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
	GPIO_Init(GPIOA,&GPIO_InitStructure);
}
 
//初始化串口1
void USART_init()
{
	USART_InitTypeDef USART_InitStructure;
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);
	
	USART_InitStructure.USART_BaudRate=115200;          //波特率为115200
	USART_InitStructure.USART_HardwareFlowControl=USART_HardwareFlowControl_None;
	USART_InitStructure.USART_Mode=USART_Mode_Rx|USART_Mode_Tx;
	USART_InitStructure.USART_Parity=USART_Parity_No;
	USART_InitStructure.USART_StopBits=USART_StopBits_1;
	USART_InitStructure.USART_WordLength=USART_WordLength_8b;
	USART_Cmd(USART1,ENABLE);
	USART_Init(USART1,&USART_InitStructure);
}

//查询法发送一字节
 char USART1_SendByte(u8 data)
{	
	int cnt = 0;
    USART_SendData(USART1,data);   //发送数据
	while(USART_GetFlagStatus(USART1,USART_FLAG_TXE)==RESET)  //如果发送失败返回0
	{
			cnt++;
			if(cnt>12000)
			return 0;
	}
   return 1;
}

//查询法接收一字符
u8 USART1_GetByte()
{
	while(USART_GetFlagStatus(USART1,USART_FLAG_RXNE)==RESET){}  //等待接收完成
		return (USART_ReceiveData(USART1));
}
 
 
u8 ReceiveData()
{
	vu32 cnt=0;
	while(1)
	{
		RxBuffer[RxCount++]=USART1_GetByte();
		if(strstr((char *)RxBuffer,"ON")!=NULL)    //对比串口接收到的字符串，为ON就返回1
		{
			RxCount=0;
			return 1;
		}
		else 
			if(strstr((char *)RxBuffer,"OFF")!=NULL) //对比窗口接收到的字符串，为OFF就返回2
			{
				RxCount=0;
				return 2;
			}
		else 
			if(RxCount>3)        //如果未接收到ON或OFF则重新接收并返回0
			{
				RxCount=0;
				return 0;
			}				
		
	}
}
 
void SendString(u8 *state)     //用来向串口调试助手发送字符串
{
	while(*state!='\0')
	USART1_SendByte(*state++);
}
 
void EmptyRxBuffer(u8 len)      //清空接收寄存数组
{
	u8 i;
	for(i=0;i<len;i++)
	RxBuffer[i]=0;
}

int main(void)
{
 
	GPIO_LED_init();   //LED有关的GPIO设置
	GPIO_USART_int();  //串口有关的GPIO设置
	USART_init();      //串口设置
	while(1)
	{
		//SendString((u8 *)("Welcome to my stm32 project\n"));
		switch(ReceiveData())  //根据接收到的字符串，执行操作
		{
			case 1:
				if((GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_5))==RESET)
                 //如果LED已经被点亮，则提示LED已是亮的
 				SendString((u8 *)("the LED has been ON\n"));
			  else 
				{
					LED_ON;
                    //否则点亮LED并提示
					SendString((u8 *)("the LED is ON now\n"));
				}
			break;
			case 2:
				if((GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_5))!=RESET)
                //如LED已是灭灯状态，则提示LED已灭
					SendString((u8 *)("the LED has been OFF\n"));
				else 
				{
					LED_OFF;
                    //否则关闭LED,并返回状态
					SendString((u8 *)("the LED is OFF now\n"));
				}
			break;
			case 0:
				SendString((u8 *)("Command erro!\n"));
			  break;			
		}
	EmptyRxBuffer(MAX);
	}
}