main.c

#include"led.h"#include"uart4.h"//封装延时函数void delay(int ms){int i,j;for(i=0;i<ms;i++){for(j=0;j<2000;j++){}}}int main(){//led初始化all_led_init();while(1){uart4_init();char i;while(1){i=getchar();putchar(i);if(i=='1'){LED1_ON();LED2_OFF();LED3_OFF();}if(i=='2'){LED2_ON();LED1_OFF();LED3_OFF();}if(i=='3'){LED3_ON();LED2_OFF();LED1_OFF();}  }}return 0;}

uart4.h

#ifndef __UART4_H__
#define __UART4_H__
#include "stm32mp1xx_uart.h"
#include "stm32mp1xx_rcc.h"
#include "stm32mp1xx_gpio.h"void uart4_init();
void putchar(char a);
char getchar();
#endif

led.h

#ifndef __LED_H__
#define __LED_H__
#include "stm32mp1xx_gpio.h"
#include "stm32mp1xx_rcc.h"
void all_led_init();
void LED1_ON();
void LED2_ON();
void LED3_ON();
void LED1_OFF();
void LED2_OFF();
void LED3_OFF();#endif

uart4.c

 #include "uart4.h"void uart4_init()
{//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PB2和PG11管脚复用GPIOB->MODER &= (~(0x3<<4));GPIOB->MODER |= (0x1<<5);GPIOG->MODER &= (~(0x3<<22));GPIOG->MODER |= (0x1<<23);GPIOB->AFRL &=(~(0xF<<8));GPIOB->AFRL |= (0X1<<11);GPIOG->AFRH &=(~(0xF<<12));GPIOG->AFRH |=  (0X3<<13);//设置串口不使能 UE=0USART4->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115200USART4->BRR=0x22B;//使能发送器USART4->CR1 |= (0X1<<3);//使能接收器USART4->CR1 |= (0X1<<2);//使能uart4USART4->CR1 |= (0X1);}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)));
}char getchar()
{char a;//先判断接收数据寄存器种有没有准备好的数据//如果数据没有准备好则阻塞等到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;
}

led.c

#include "led.h"void all_led_init()//led灯的初始化
{//GPIOE/GPIOF时钟使能RCC->MP_AHB4ENSETR  |= (0x3<<4);//PE10设置为输出GPIOE->MODER &= (~(0X3<<20));GPIOE->MODER |= (0X1<<20);//PF10设置为输出GPIOF->MODER &= (~(0X3<<20));GPIOF->MODER |= (0X1<<20);//PE8设置为输出GPIOE->MODER &= (~(0X3<<16));GPIOE->MODER |= (0X1<<16);//PE10设置为推挽输出GPIOE->OTYPER &= (~(0X1<<10));//PF10设置为推挽输出GPIOF->OTYPER &= (~(0X1<<10));//PE8设置为推挽输出GPIOE->OTYPER &= (~(0X1<<8));//PE10设置为低速输出GPIOE->OSPEEDR &= (~(0X3<<20));//PF10设置为低速输出GPIOF->OSPEEDR &= (~(0X3<<20));//PE8设置为低速输出GPIOE->OSPEEDR &= (~(0X3<<16));//PE10无上拉下拉电阻GPIOE->PUPDR &= (~(0X3<<20));//PF10无上拉下拉电阻GPIOF->PUPDR &= (~(0X3<<20));//PE8无上拉下拉电阻GPIOE->PUPDR &= (~(0X3<<16));//三盏灯默认输出低电平GPIOE->ODR &= (~(0X1<<10));GPIOF->ODR &= (~(0X1<<10));GPIOE->ODR &= (~(0X1<<8));
}//led1亮
void LED1_ON()
{GPIOE->ODR |= (0X1<<10);
}
//led2亮
void LED2_ON()
{GPIOF->ODR |= (0X1<<10);
}
//led1亮
void LED3_ON()
{GPIOE->ODR |= (0X1<<8);
}//LED1灭
void LED1_OFF()
{GPIOE->ODR &= (~(0X1<<10));
}
//LED2灭
void LED2_OFF()
{GPIOF->ODR &= (~(0X1<<10));
}
//LED3灭
void LED3_OFF()
{GPIOE->ODR &= (~(0X1<<8));
}