4.15作业

最新推荐文章于 2025-07-26 16:19:40 发布

原创最新推荐文章于 2025-07-26 16:19:40 发布 · 388 阅读

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文章标签：

#单片机 #嵌入式硬件

文章详细描述了如何在STM32MP1xx平台上使用UART4进行串口通信，包括初始化、字符串收发函数的封装，以及GPIO配置以控制外部设备。还展示了如何处理字符输入和输出，以及实现字符串比较的strcmp函数。

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作业要求：实现字符串数据收发函数的封装

程序代码：

main.c

#include "uart4.h"

//手动封装延时函数

void delay_ms(int ms)

{

	int i,j;

	for(i=0;i<ms;i++)

	{

		for(j=0;j<2000;j++)

		{



		}

	}

}

int main()

{

	//uart4初始化

	uart4_config();

	//char a;

	char b[100];

	while(1)

	{

	//	a=getchar();//接收一个字符

	//	putchar(a+1);//现象，发送a，输出b

		gets(b);

		puts(b);

	}

	return 0;

}

uart4.c

#include "uart4.h"

void uart4_config()
{
    //使能GPIOB\GPIOG\UART4外设时钟
    RCC->MP_AHB4ENSETR |=(0X1<<1);
    RCC->MP_AHB4ENSETR |=(0X1<<6);
    RCC->MP_APB1ENSETR |=(0X1<<16);
    //设置PG11和PB2为管脚复用功能
    //PB2
    GPIOB->MODER &=(~(0x3<<4));
    GPIOB->MODER |=(0x2<<4);
    //PG11
    GPIOG->MODER &= (~(0x3<<22));
    GPIOG->MODER |= (0x2<<22);
    //设置PG11为UART4_TX功能
    GPIOG->AFRH &= (~(0xf<<12));
    GPIOG->AFRH |= (0X6<<12);
    //设置PB2为UART4_RX功能
    GPIOB->AFRL &= (~(0xf<<8));
    GPIOB->AFRL |= (0X8<<8);
    //设置串口不使能
    USART4->CR1 &= (~0x1);
    //设置8位数据位
    USART4->CR1 &= (~(0x1<<12));
    USART4->CR1 &= (~(0x1<<28));
    //设置没有校验位
    USART4->CR1 &= (~(0x1<<10));
    //设置时钟频率不分频
    USART4->PRESC &= (~0xf);
    //设置16倍过采样
    USART4->CR1 &= (~(0x1<<15));
    //设置1位停止位
    USART4->CR2 &= (~(0x3<<12));
    //设置波特率为115200
    USART4->BRR=0X22B;
    //使能发送器
    USART4->CR1 |= (0X1<<3);
    //使能接收器
    USART4->CR1 |= (0X1<<2);
    //使能串口
    USART4->CR1 |= (0X1<<0);
}

//发送单个字符
void putchar(char dat)
{
    //当发送数据寄存器中没有数据时可以发送
    while (!(USART4->ISR & (0x1<<7)));//当TDR中有数据时阻塞等待没有数据
    USART4->TDR = dat;//向发送数据寄存器中写入数据
    //等大传输完成函数结束
    while (!(USART4->ISR & (0x1<<6)));
}

//接收单个字符
char getchar()
{
    //当接收数据寄存器中有有效数据时读取
    while (!(USART4->ISR & (0x1<<5)));
    //将读取到的数据返回
    return USART4->RDR;
}

//发送字符串
void puts(char *s)
{
    while(1)
    {
        if(*s == '\0')
        break;
        putchar(*s);
        s++;
    }
    putchar('\n');
}

//接收字符串
char gets(char *s)
{
    while(1)
    {
        //循环接收单个字符，当检测到回车'\r'被按下，结束
         *s=getchar();
         putchar(*s);
        if(*s == '\r')
            break;
         s++;
    }
    s++;
    *s='\0';
    putchar('\n');
    return USART4->RDR; 
}

uart4.h

#ifndef __UART4_H__
#define __UART4_H__
#include "stm32mp1xx_gpio.h"
#include "stm32mp1xx_rcc.h"
#include "stm32mp1xx_uart.h"
void uart4_config();
void putchar(char dat);
char getchar();
void puts(char *s);
char gets(char *s);
#endif

运行结果：

作业要求：

程序代码：

main.C

#include "uart4.h"

//手动封装延时函数

void delay_ms(int ms)

{

	int i,j;

	for(i=0;i<ms;i++)

	{

		for(j=0;j<2000;j++)

		{



		}

	}

}

int main()

{

	//uart4初始化

	uart4_config();

	//char a;

	char b[100];

	while(1)

	{

	//	a=getchar();//接收一个字符

	//	putchar(a+1);//现象，发送a，输出b

		gets(b);

		

	if(strcmp(b,"1on") == 0)

	{

		GPIOE->ODR |=(0x1<<10);

	}

	else if(strcmp(b,"1off") == 0)

	{

		GPIOE->ODR &=(~(0x1<<10));

	}

	

	if(strcmp(b,"2on") == 0)

	{

		GPIOE->ODR |=(0x1<<8);

	}

	else if(strcmp(b,"2off") == 0)

	{

		GPIOE->ODR &=(~(0x1<<8));

	}

	

	if(strcmp(b,"3on") == 0)

	{

		GPIOF->ODR |=(0x1<<10);

	}

	else if(strcmp(b,"3off") == 0)

	{

		GPIOF->ODR &=(~(0x1<<10));

	}

	}

	puts(b);

	return 0;

}

uart4.c

#include "uart4.h"

void uart4_config()
{
    //使能GPIOB\GPIOG\UART4外设时钟
    RCC->MP_AHB4ENSETR |=(0X1<<1);
    RCC->MP_AHB4ENSETR |=(0X1<<6);
    RCC->MP_APB1ENSETR |=(0X1<<16);
    //设置PG11和PB2为管脚复用功能
    //PB2
    GPIOB->MODER &=(~(0x3<<4));
    GPIOB->MODER |=(0x2<<4);
    //PG11
    GPIOG->MODER &= (~(0x3<<22));
    GPIOG->MODER |= (0x2<<22);
    //设置PG11为UART4_TX功能
    GPIOG->AFRH &= (~(0xf<<12));
    GPIOG->AFRH |= (0X6<<12);
    //设置PB2为UART4_RX功能
    GPIOB->AFRL &= (~(0xf<<8));
    GPIOB->AFRL |= (0X8<<8);
    //设置串口不使能
    USART4->CR1 &= (~0x1);
    //设置8位数据位
    USART4->CR1 &= (~(0x1<<12));
    USART4->CR1 &= (~(0x1<<28));
    //设置没有校验位
    USART4->CR1 &= (~(0x1<<10));
    //设置时钟频率不分频
    USART4->PRESC &= (~0xf);
    //设置16倍过采样
    USART4->CR1 &= (~(0x1<<15));
    //设置1位停止位
    USART4->CR2 &= (~(0x3<<12));
    //设置波特率为115200
    USART4->BRR=0X22B;
    //使能发送器
    USART4->CR1 |= (0X1<<3);
    //使能接收器
    USART4->CR1 |= (0X1<<2);
    //使能串口
    USART4->CR1 |= (0X1<<0);


     // 使能GPIO的外设时钟
    RCC->MP_AHB4ENSETR |= (0X3 << 4);
    // 设置PE10为输出
    GPIOE->MODER &= (~(0X3 << 20));
    GPIOE->MODER |= (0x1 << 20);
    // 设置PF10为输出
    GPIOF->MODER &= (~(0X3 << 20));
    GPIOF->MODER |= (0x1 << 20);
    // 设置PE8为输出
    GPIOE->MODER &= (~(0X3 << 16));
    GPIOE->MODER |= (0x1 << 16);
    // 设置PB6为输出
    GPIOB->MODER &= (~(0X3 << 12));
    GPIOB->MODER |= (0x1 << 12);
 
    // 设置PE10为推挽输出
    GPIOE->OTYPER &= (~(0X1 << 10));
    // 设置PF10为推挽输出
    GPIOF->OTYPER &= (~(0X1 << 10));
    // 设置PE8为推挽输出
    GPIOE->OTYPER &= (~(0X1 << 8));
    // 设置PB6为推挽输出
    GPIOB->OTYPER &= (~(0X1 << 6));
 
    // 设置PE10为低速输出
    GPIOE->OSPEEDR &= (~(0X3 << 20));
    // 设置PF10为低速输出
    GPIOF->OSPEEDR &= (~(0X3 << 20));
    // 设置PE8为低速输出
    GPIOE->OSPEEDR &= (~(0X3 << 16));
    // 设置PB6为低速输出
    GPIOB->OSPEEDR &= (~(0X3 << 12));
 
    // 设置PE10输出无上拉下拉电阻
    GPIOE->PUPDR &= (~(0X3 << 20));
    // 设置PF10输出无上拉下拉电阻
    GPIOF->PUPDR &= (~(0X3 << 20));
    // 设置PE8输出无上拉下拉电阻
    GPIOE->PUPDR &= (~(0X3 << 16));
    // 设置PB6输出无上拉下拉电阻
    GPIOB->PUPDR &= (~(0X3 << 12));
 
    // 三盏灯默认是关闭
    GPIOE->ODR &= (~(0X1 << 10));
    GPIOF->ODR &= (~(0X1 << 10));
    GPIOE->ODR &= (~(0X1 << 8));

}

//发送单个字符
void putchar(char dat)
{
    //当发送数据寄存器中没有数据时可以发送
    while (!(USART4->ISR & (0x1<<7)));//当TDR中有数据时阻塞等待没有数据
    USART4->TDR = dat;//向发送数据寄存器中写入数据
    //等大传输完成函数结束
    while (!(USART4->ISR & (0x1<<6)));
}

//接收单个字符
char getchar()
{
    //当接收数据寄存器中有有效数据时读取
    while (!(USART4->ISR & (0x1<<5)));
    //将读取到的数据返回
    return USART4->RDR;
}

//发送字符串
void puts(char *s)
{
    while(1)
    {
        if(*s == '\0')
        break;
        putchar(*s);
        s++;
    }
    putchar('\n');
    putchar('\r');
}

//接收字符串
void gets(char *s)
{
    while(1)
    {
        //循环接收单个字符，当检测到回车'\r'被按下，结束
         *s=getchar();
         putchar(*s);
        if(*s == '\r')
            break;
         s++;
    }
    *s='\0';
    putchar('\n');
    putchar('\r');
}


//判断函数
int strcmp(char *s, char *p)
{
    while(*s == *p&&*s )
    {
        s++;
        p++;
    } 
    return *s-*p;   
}

uart4.h

#ifndef __UART4_H__
#define __UART4_H__
#include "stm32mp1xx_gpio.h"
#include "stm32mp1xx_rcc.h"
#include "stm32mp1xx_uart.h"


void uart4_config();
void putchar(char dat);
char getchar();
void puts(char *s);
void gets(char *s);
int strcmp(char *s, char *p);
#endif