2024.3.21 ARM

串口控制三盏灯亮灭

main.c

#include "uart4.h"


int main()
{
	//串口初始化
	uart4_init();
	//led初始化
	led_init();
	char i;
	//char s[128];
	int count = 0;
	int count2 = 0;
	int count3 = 0;
	while (1)
	{
		i = getchar();
		putchar(i);
		//最终的现象：键盘输入a，串口工具显示a
		//gets(s);
		//puts(s);
		if (i == '1')
		{
			count++;
			if (count % 2 == 1)
				LED1_ON();
			else
				LED1_OFF();
		}
		if (i == '2')
		{
			count2++;
			if (count2 % 2 == 1)
				LED2_ON();
			else
				LED2_OFF();
		}
		if (i == '3')
		{
			count3++;
			if (count3 % 2 == 1)

				LED3_ON();
			else
				LED3_OFF();
		}

	}
	return 0;
}

uart4.h

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

void uart4_init();
void putchar(char a);
char getchar();
void gets(char *s);
void puts(char *s);

void led_init();
void LED1_ON();
void LED2_ON();
void LED3_ON();
void LED1_OFF();
void LED2_OFF();
void LED3_OFF();
int my_strcmp(const char *src1, const char *src2);
#endif

uart4.c

#include "uart4.h"
#include "led.h"
int my_strcmp(const char *src1, const char *src2)
{
    while (*src1 == *src2)
    {
        if (*src1 == 0)
        {
            return 0;
        }
        src1++;
        src2++;
    }
    return (*src1 - *src2);
}

void led_init()
{
    RCC->MP_AHB4ENSETR |= (0x3 << 4); //使能GPIOF GPIOE
    GPIOE->MODER &= (~(0x3 << 20));   //PE10 清零
    GPIOE->MODER |= (0x1 << 20);      //PE10 管脚复用
    GPIOE->MODER &= (~(0x3 << 16));   //PE8 清零
    GPIOE->MODER |= (0x1 << 16);      //PE8 管脚复用
    GPIOF->MODER &= (~(0x3 << 20));   //PF10 清零
    GPIOF->MODER |= (0x1 << 20);      //PF10 管脚复用
    //设置推挽模式
    GPIOE->OTYPER &= (~(0x1 << 10));
    GPIOF->OTYPER &= (~(0x1 << 10));
    GPIOE->OTYPER &= (~(0x1 << 8)); //PE8
    //设置低速
    GPIOE->OSPEEDR &= (~(0x3 << 20));
    GPIOF->OSPEEDR &= (~(0x3 << 20));
    GPIOE->OSPEEDR &= (~(0x3 << 16)); //PE8
    //设置无上拉下拉
    GPIOE->PUPDR &= (~(0x3 << 20));
    GPIOF->PUPDR &= (~(0x3 << 20));
    GPIOE->PUPDR &= (~(0x3 << 16));
    //设置低电平输出 灯灭
    GPIOE->ODR &= (~(0x1 << 10));
    GPIOF->ODR &= (~(0x1 << 10));
    GPIOE->ODR &= (~(0x1 << 8));
}


void uart4_init()
{
    //使能GPIOB GPIOG UART4外设时钟
    RCC->MP_AHB4ENSETR |= (0x1 << 1);  //GPIOB
    RCC->MP_AHB4ENSETR |= (0x1 << 6);  //GPIOG
    RCC->MP_APB1ENSETR |= (0X1 << 16); //UART4
    //设置PB2和PG11管脚复用
    //PB2
    GPIOB->MODER &= (~(0x3 << 4));
    GPIOB->MODER |= (0x2 << 4);
    //PG11
    GPIOG->MODER &= (~(0x3 << 22));
    GPIOG->MODER |= (0x2 << 22);

    GPIOB->AFRL &= (~(0XF << 8));
    GPIOB->AFRL |= (0x8 << 8);
    GPIOB->AFRH &= (~(0XF << 12));
    GPIOG->AFRH |= (0x6 << 12);
    //设置串口不使能 UE=0
    USART4->CR1 &= (~(0X1));
    //设置8位数据位
    USART4->CR1 &= (~(0x1 << 12));
    USART4->CR1 &= (~(0x1 << 28));
    //设置没有奇偶校验位
    USART4->CR1 &= (~(0x1 << 10));
    //设置1位停止位
    USART4->CR2 &= (~(0x3 << 12));
    //设置16倍过采样
    USART4->CR1 &= (~(0x1 << 15));
    //设置时钟不分频
    USART4->PRESC &= (~(0xF));
    //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uart4
    USART4->CR1 |= (0x1 << 0);
}

//发送一个字符
void putchar(char a)
{
    //先判断发送数据寄存器是否为空
    //不为空阻塞等待
    while (!(USART4->ISR & (0x1 << 7)))
        ;
    //为空向发送数据寄存器写入a的数据
    USART4->TDR = a; //写入数据
    //写入完成需要判断发送是否完成，不完成阻塞等待，完成了则函数结束
    while (!(USART4->ISR & (0x1 << 6)))
        ;
}

//接收一个字符
char getchar()
{
    char a;
    //先判断接收数据寄存器中有没有准备好的数据
    //如果数据没有准备好则阻塞等待
    while (!(USART4->ISR & (0x1 << 5)))
        ;
    //如果数据准备好了则读取
    a = USART4->RDR;
    //读取完毕将读取到的数据返回
    return a;
}

//发送字符串
void puts(char *s)
{
    while (*s)
    {
        putchar(*s);
        s++;
    }
    putchar('\n'); // '\n'切换到下一行
    putchar('\r'); //'\n'回车键，切换到行头
}

//接收字符串函数
void gets(char *s)
{
    while (1)
    {
        *s = getchar();
        putchar(*s);
        if ((*s) == '\r')
            break;
        s++;
    }
    *s = '\0';
    putchar('\n'); //换行
}