STM32串口USART1接收字符串

浅浅的花香味﹌ 2022-12-15 14:11 450阅读 0赞

STM32F407ZE开发板实现使用串口USART1接收、发送字符串实例  
具体代码及解析如下：

main.c部分

#include <stm32f4xx.h> 
    #include "led.h"
    #include "ustart.h"
    #include <string.h>
    
    int main()
    { 
    	LED_Init();
    	USART1_Init();
    	USART_SendString(USART1, "Hello world!\r\n");
    
    	while(1)
    	{ 
    		if(Receive_Flag == 1)						//接收数据标志位等于1（接收完毕，停止接收）
    			Receive_Flag = 0;						//接收数据标志位置0（可以开始接收）
    	}
    }

ustart.h部分

#ifndef USTART_H
    #define USTART_H
    
    #include <stm32f4xx.h>
    #include <stm32f4xx_usart.h>
    #include <stdio.h>
    #include "sys.h"
    
    extern char USART1_ReceiveData[50];								//接收PC端发送过来的字符
    extern int Receive_Flag;
    
    void USART1_Init();
    void USART_SendString(USART_TypeDef* USARTx, char *DataString);
    #endif

ustart.c部分

#include "ustart.h"
    #include <string.h>
    
    int fputc(int ch, FILE *f) 
    { 
    	/* 发送一个字节数据到串口 */
    	USART_SendData(USART1, (uint8_t) ch); //程序开始时，会发送一次数据，ch是系统分配的（可能是0），串口会显示大概两个空格的内容
    	/* 等待发送完毕 */
    	while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
    	return (ch);
    }
    
    void USART1_Init()
    { 
    	GPIO_InitTypeDef 	GPIOInit_Struct;
    	USART_InitTypeDef 	USARTInit_Struct;
    	NVIC_InitTypeDef  	USARTNVIC_Struct;
    	
    	//1、使能时钟
    	RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
    	
    	//2、初始化对应的IO引脚复用为USART1功能
    	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE);
    	
    	GPIOInit_Struct.GPIO_Pin 	= GPIO_Pin_9 | GPIO_Pin_10;
    	GPIOInit_Struct.GPIO_Mode	= GPIO_Mode_AF;
    	GPIOInit_Struct.GPIO_OType	= GPIO_OType_PP;
    	GPIOInit_Struct.GPIO_Speed 	= GPIO_Fast_Speed;
    	GPIOInit_Struct.GPIO_PuPd	= GPIO_PuPd_UP;
    	GPIO_Init(GPIOA,&GPIOInit_Struct);
    	
    	//将PA9 PA10复用为USART1功能
    	GPIO_PinAFConfig(GPIOA,GPIO_PinSource9,GPIO_AF_USART1);
    	GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_USART1);
    	
    	//3、USART1初始化
    	USARTInit_Struct.USART_BaudRate 	= 115200; 								//波特率
    	USARTInit_Struct.USART_Parity		= USART_Parity_No;						//无校验位
    	USARTInit_Struct.USART_StopBits		= USART_StopBits_1;						//1位停止位
    	USARTInit_Struct.USART_WordLength	= USART_WordLength_8b;					//8位数据位
    	USARTInit_Struct.USART_Mode			= USART_Mode_Rx | USART_Mode_Tx;		//收发模式
    	USARTInit_Struct.USART_HardwareFlowControl	= USART_HardwareFlowControl_None;//无硬件控制流
    	USART_Init(USART1,&USARTInit_Struct);
    	
    	//开启串口终端
    	USART_ITConfig(USART1,USART_IT_RXNE,ENABLE);
    	
    	USARTNVIC_Struct.NVIC_IRQChannel = USART1_IRQn;//stm32f4xx.h
    	USARTNVIC_Struct.NVIC_IRQChannelPreemptionPriority = 0;
    	USARTNVIC_Struct.NVIC_IRQChannelSubPriority        = 0;
    	USARTNVIC_Struct.NVIC_IRQChannelCmd	= ENABLE;
    	NVIC_Init(&USARTNVIC_Struct);
    	
    	//4、开启串口
    	USART_Cmd(USART1,ENABLE);
    }
    
    void USART_SendString(USART_TypeDef* USARTx, char *DataString)
    { 
    	int i = 0;
    	USART_ClearFlag(USARTx,USART_FLAG_TC);										//发送字符前清空标志位（否则缺失字符串的第一个字符）
    	while(DataString[i] != '\0')												//字符串结束符
    	{ 
    		USART_SendData(USARTx,DataString[i]);									//每次发送字符串的一个字符
    		while(USART_GetFlagStatus(USARTx,USART_FLAG_TC) == 0);					//等待数据发送成功
    		USART_ClearFlag(USARTx,USART_FLAG_TC);									//发送字符后清空标志位
    		i++;
    	}
    }
    
    char USART_ReceiveString[50];													//接收PC端发送过来的字符
    int Receive_Flag = 0;															//接收消息标志位
    int Receive_sum = 0;															//数组下标
    void USART1_IRQHandler(void)
    { 
    	if(USART_GetITStatus(USART1,USART_IT_RXNE) == 1)							//USART_FLAG_RXNE判断数据，== 1则有数据
    	{ 
    		if(Receive_sum > 49)													//数组能存放50个字节的数据 
    		{ 
    			USART_ReceiveString[49] = '\0';										//数据字节超过50位时，将最后一位设置为\0 
    			Receive_Flag = 1;													//接收标志位置1，停止接收数据
    			Receive_sum = 0;													//数组下标置0
    		}
    		
    		if(Receive_Flag == 0)													//接收标志位等于0，开始接收数据
    		{ 
    			USART_ReceiveString[Receive_sum] = USART_ReceiveData(USART1);		//通过USART1串口接收字符
    			Receive_sum++;														//数组下标++
    		}
    		
    		if(Receive_sum >= 2)													//数组下标大于2
    		{ 
    			if(USART_ReceiveString[Receive_sum-2] == '\r' && USART_ReceiveString[Receive_sum-1] == '\n' )
    			{ 
    				USART_ReceiveString[Receive_sum-1] = '\0';						
    				USART_ReceiveString[Receive_sum-2] = '\0';
    				Receive_Flag = 1;												//接收标志位置1，停止接收数据
    				Receive_sum = 0;												//数组下标置0
    				printf("%s\r\n",USART_ReceiveString);					
    
    				if(strcmp(USART_ReceiveString,"hello") == 0)
    				{ 
    					PFout(9) = !PFout(9);
    				}
    				if(strcmp(USART_ReceiveString,"world") == 0)
    				{ 
    					PFout(10) = !PFout(10);
    				}
    				if(strcmp(USART_ReceiveString,"jiajia") == 0)
    				{ 
    					PEout(13) = !PEout(13);
    				}
    				if(strcmp(USART_ReceiveString,"haha") == 0)
    				{ 
    					PEout(14) = !PEout(14);
    				}
    			}		
    		}
    		USART_ClearITPendingBit(USART1,USART_IT_RXNE);							//接收后先清空标志位
    	}
    }

led.h部分

#ifndef _LED_H_
    #define _LED_H_
    
    #include <stm32f4xx.h>
    #include "sys.h"
    
    void LED_Init(void);
    
    #endif

led.c部分

#include "led.h"
    
    void LED_Init(void)
    { 
    	GPIO_InitTypeDef aaa;
    	
    	//1、先开启对应用到的模块时钟节拍
    	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOF,ENABLE);
    	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE,ENABLE);//PE组时钟
    
    	//2、可以初始化配置GPIO F组的9号引脚
    	aaa.GPIO_Pin   = GPIO_Pin_9 | GPIO_Pin_10;
    	aaa.GPIO_Mode  = GPIO_Mode_OUT;//输出模式
    	aaa.GPIO_Speed = GPIO_Fast_Speed;//快速 点灯和引脚速度无关
    	aaa.GPIO_OType = GPIO_OType_PP;//推挽输出
    	aaa.GPIO_PuPd  = GPIO_PuPd_UP;//内部上拉
    	GPIO_Init(GPIOF,&aaa);
    	
    	
    	aaa.GPIO_Pin   = GPIO_Pin_13 | GPIO_Pin_14;
    	GPIO_Init(GPIOE,&aaa);
    	
    	//初始化完成 灭掉4盏灯
    	PFout(9)  = 1;
    	PFout(10) = 1;
    	PEout(13) = 1;
    	PEout(14) = 1;
    
    }

sys.h部分

#ifndef __SYS_H
    #define __SYS_H 
    #include "stm32f4xx.h" 
    
    //IO口操作宏定义
    #define BITBAND(addr, bitnum) ((addr & 0xF0000000)+0x2000000+((addr & 0xFFFFF)<<5)+(bitnum<<2)) 
    #define MEM_ADDR(addr) *((volatile unsigned long *)(addr)) 
    #define BIT_ADDR(addr, bitnum) MEM_ADDR(BITBAND(addr, bitnum)) 
    //IO口地址映射
    #define GPIOA_ODR_Addr (GPIOA_BASE+20) //0x40020014
    #define GPIOB_ODR_Addr (GPIOB_BASE+20) //0x40020414 
    #define GPIOC_ODR_Addr (GPIOC_BASE+20) //0x40020814 
    #define GPIOD_ODR_Addr (GPIOD_BASE+20) //0x40020C14 
    #define GPIOE_ODR_Addr (GPIOE_BASE+20) //0x40021014 
    #define GPIOF_ODR_Addr (GPIOF_BASE+20) //0x40021414 
    #define GPIOG_ODR_Addr (GPIOG_BASE+20) //0x40021814 
    #define GPIOH_ODR_Addr (GPIOH_BASE+20) //0x40021C14 
    #define GPIOI_ODR_Addr (GPIOI_BASE+20) //0x40022014 
    
    #define GPIOA_IDR_Addr (GPIOA_BASE+16) //0x40020010 
    #define GPIOB_IDR_Addr (GPIOB_BASE+16) //0x40020410 
    #define GPIOC_IDR_Addr (GPIOC_BASE+16) //0x40020810 
    #define GPIOD_IDR_Addr (GPIOD_BASE+16) //0x40020C10 
    #define GPIOE_IDR_Addr (GPIOE_BASE+16) //0x40021010 
    #define GPIOF_IDR_Addr (GPIOF_BASE+16) //0x40021410 
    #define GPIOG_IDR_Addr (GPIOG_BASE+16) //0x40021810 
    #define GPIOH_IDR_Addr (GPIOH_BASE+16) //0x40021C10 
    #define GPIOI_IDR_Addr (GPIOI_BASE+16) //0x40022010 
     
    //STM32中 对寄存器的访问 是不能单独访问寄存器的单个bit 只能以32bit地址访问寄存器
    //这些位为只写形式，只能在字(word)--4byte、半字2byte 或字节模式下访问 
    //IO口操作,只对单一的IO口!
    //确保n的值小于16!
    #define PAout(n) BIT_ADDR(GPIOA_ODR_Addr,n) //输出 
    #define PAin(n) BIT_ADDR(GPIOA_IDR_Addr,n) //输入 
    
    #define PBout(n) BIT_ADDR(GPIOB_ODR_Addr,n) //输出 
    #define PBin(n) BIT_ADDR(GPIOB_IDR_Addr,n) //输入 
    
    #define PCout(n) BIT_ADDR(GPIOC_ODR_Addr,n) //输出 
    #define PCin(n) BIT_ADDR(GPIOC_IDR_Addr,n) //输入 
    
    #define PDout(n) BIT_ADDR(GPIOD_ODR_Addr,n) //输出 
    #define PDin(n) BIT_ADDR(GPIOD_IDR_Addr,n) //输入 
    
    #define PEout(n) BIT_ADDR(GPIOE_ODR_Addr,n) //输出 
    #define PEin(n) BIT_ADDR(GPIOE_IDR_Addr,n) //输入
    
    #define PFout(n) BIT_ADDR(GPIOF_ODR_Addr,n) //输出 
    #define PFin(n) BIT_ADDR(GPIOF_IDR_Addr,n) //输入
    
    #define PGout(n) BIT_ADDR(GPIOG_ODR_Addr,n) //输出 
    #define PGin(n) BIT_ADDR(GPIOG_IDR_Addr,n) //输入
    
    #define PHout(n) BIT_ADDR(GPIOH_ODR_Addr,n) //输出 
    #define PHin(n) BIT_ADDR(GPIOH_IDR_Addr,n) //输入
    
    #define PIout(n) BIT_ADDR(GPIOI_ODR_Addr,n) //输出 
    #define PIin(n) BIT_ADDR(GPIOI_IDR_Addr,n) //输入
    
    
    #endif