ARM_day6：实现字符串数据收发函数的封装

2024-04-22 19:21:21

程序代码：

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);
#endif

uart4.c：

#include "uart4.h"

void uart4_config()
{
    //使能GPIOB\GPIOG\UART4的外设时钟
    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++;
    }
    //发送一个回车
    putchar('\r');//回车
     //换行
    putchar('\n');
}
//接收字符串
void gets(char *s)
{
    while(1)
    {
        *s=getchar();
        //循环接收单个字符，检测到回车键被按下，结束'\r'
        if(*s=='\r')
        {
            break;
        }
        putchar(*s);
        s++;
    }
     //在接收的字符串最后补上一个'\0'
     *s='\0';
   //发送一个'\n'表示在串口下一行进行显示
   putchar('\n');
}

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 s[128];
    while(1)
    {
		gets(s);
		puts(s);
    }
    return 0;
}

运行结果：

2、通过串口发送指令，控制LED\蜂鸣器等外设工作

程序代码：

uart4.h:

#ifndef __UART4_H__
#define __UART4_H__
#include "stm32mp1xx_gpio.h"
#include "stm32mp1xx_rcc.h"
#include "stm32mp1xx_uart.h"
void led_init();
void uart4_init();
void myputchar(char i);
char mygetchar();
void puts(char *s);
char *gets();
int mystrcmp(char *dest, char *src);

#endif

uart4.c:

#include "uart4.h"

char buf[51] = {0};
// led数据初始化
void led_init()
{
    // 设置GPIOE/GPIOF时钟使能
    RCC->MP_AHB4ENSETR |= (0x3 << 4);
    // 设置PE10/PE8/PF10为输出模式
    GPIOE->MODER &= (~(0x3 << 20));
    GPIOE->MODER |= (0x1 << 20);
    GPIOE->MODER &= (~(0x3 << 16));
    GPIOE->MODER |= (0x1 << 16);
    GPIOF->MODER &= (~(0x3 << 20));
    GPIOF->MODER |= (0x1 << 20);
    // 设置PE10/PE8/PF10为推挽输出
    GPIOE->OTYPER &= (~(0x1 << 10));
    GPIOE->OTYPER &= (~(0X1 << 8));
    GPIOF->OTYPER &= (~(0x1 << 10));
    // 设置PE10/PE8/PF10输出速度为低速
    GPIOE->OSPEEDR &= (~(0x3 << 20));
    GPIOE->OSPEEDR &= (~(0X3 << 16));
    GPIOF->OSPEEDR &= (~(0x3 << 20));
    // 设置PE10/PE8/PF10无上拉下拉
    GPIOE->PUPDR &= (~(0x3 << 20));
    GPIOE->PUPDR &= (~(0X3 << 16));
    GPIOF->PUPDR &= (~(0X3 << 20));
}

// 串口数据初始化
void uart4_init()
{
    // 设置UART4的RCC时钟使能
    // RCC_MP_APB1ENSETR[16]->1
    RCC->MP_APB1ENSETR |= (0x1 << 16);
    // 设置GPIOB和GPIOG的时钟使能
    // RCC_MP_AHB4ENSETR[6]->1
    // RCC_MP_AHB4ENSETR[1]->1
    RCC->MP_AHB4ENSETR |= (0x1 << 1);
    RCC->MP_AHB4ENSETR |= (0X1 << 6);
    // 设置PG11和PB2功能复用为UART4功能
    // PG11
    // GPIOG_MODER[23:22]->10
    GPIOG->MODER &= (~(0X3 << 22));
    GPIOG->MODER |= (0X2 << 22);
    // GPIOG_AFRH[15:12]->0110
    GPIOG->AFRH &= (~(0xf << 12));
    GPIOG->AFRH |= (0x6 << 12);
    // PB2
    // GPIOB_MODER[5:4]->10
    // GPIOB_AFRL[11:8]->1000
    GPIOB->MODER &= (~(0x3 << 4));
    GPIOB->MODER |= (0X2 << 4);
    GPIOB->AFRL &= (~(0xF << 8));
    GPIOB->AFRL |= (0x8 << 8);
    // 禁用串口
    USART4->CR1 &= (~0x1);
    // 设置数据8个数据位 CR1[28]->0  CR1[12]-》0
    USART4->CR1 &= (~(0X1 << 28));
    USART4->CR1 &= (~(0X1 << 12));
    // 设置没有校验位CR1[10]->0
    USART4->CR1 &= (~(0X1 << 10));
    // 设置1个停止位CR2[13:12]->00
    USART4->CR2 &= (~(0x3 << 12));
    // 设置16倍采样 CR1[15]->0
    USART4->CR1 &= (~(0X1 << 15));
    // 设置波特率为115200 BRR=0X22B
    USART4->BRR |= 0X22B;
    // 设置1分频 PRESC[3:0]->0000
    USART4->PRESC &= (~(0XF));
    // 使能发送器 CR1[3]->1
    USART4->CR1 |= (0X1 << 3);
    // 使能接收器 CR1[2]->1
    USART4->CR1 |= (0X1 << 2);
    // 使能串口 CR1[0]->1
    USART4->CR1 |= (0X1);
}
// 封装函数发送一个字符数据
void myputchar(char c)
{
    // 判断发送数据寄存器有没有数据，没有数据时可以发送
    while (!(USART4->ISR & (0X1 << 7)))
        ;
    USART4->TDR = c; // 将要发送的数据保存在发送寄存器中
    while (!(USART4->ISR & (0X1 << 6)))
        ; // 数据传输完成，函数结束
}
char mygetchar()
{
    char c;
    // 判断是否有数据准备好
    while (!(USART4->ISR & (0X1 << 5)))
        ; // 数据传输完成，函数结束
    c = USART4->RDR;
    return c;
}

// 输出一个字符串
void puts(char *s)
{
    while (*s)
    {
        myputchar(*s++);
    }
    myputchar('\n'); // 切换到下一行
    myputchar('\r'); // 切换到一行的开头
}

// 读取一个字符串
char *gets()
{
    unsigned int i;
    for (i = 0; i < 50; i++)
    {
        buf[i] = mygetchar();
        myputchar(buf[i]);
        if (buf[i] == '\r')
            break;
    }
    buf[i] = '\0';
    myputchar('\n');
    myputchar('\r');

    return buf;
}

int mystrcmp(char *dest, char *src)
{
    while (*dest && *src)
    {
        if (*dest != *src)
            return *dest - *src;
        dest++;
        src++;
    }
    if (*dest == *src)
        return 0;
}

main.c:

#include "uart4.h"

int main()
{
    led_init();
    // 1.串口的初始化
    uart4_init();
    char *str;
    // char a;

    // 现象是发送一个a串口工具打印一个b
    while (1)
    {
        str = gets();
        puts(str);
        // // 2.从串口读取一个字符
        // a = mygetchar();
        // // 3.将读取到的字符+1发送回去
        // myputchar(a + 1);

        if (mystrcmp(str, "led1_on") == 0)
            GPIOE->ODR |= (0x1 << 10);
        else if (mystrcmp(str, "led1_off") == 0)
            GPIOE->ODR &= ~(0x1 << 10);
        else if (mystrcmp(str, "led2_on") == 0)
            GPIOF->ODR |= (0x1 << 10);
        else if (mystrcmp(str, "led2_off") == 0)
            GPIOF->ODR &= ~(0x1 << 10);
        else if (mystrcmp(str, "led3_on") == 0)
            GPIOE->ODR |= (0x1 << 8);
        else if (mystrcmp(str, "led3_off") == 0)
            GPIOE->ODR &= ~(0x1 << 8);
    }
    return 0;
}

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