串口发送控制命令，实现一些外设LED 风扇

uart4.c

#include "uart4.h"void uart4_config()
{//1.使能GPIOB\GPIOG\UART4外设时钟RCC->MP_AHB4ENSETR |= (0x1 << 1);RCC->MP_AHB4ENSETR |= (0x1 << 6);RCC->MP_APB1ENSETR |= (0x1 << 16);//===============================================//led时钟使能RCC->MP_AHB4ENSETR |= (0x3 << 4);//设置PE10输出GPIOE->MODER &= (~(0x3<<20));GPIOE->MODER |= (0x1<<20);//设置PE10为推晚输出GPIOE->OTYPER &= (~(0x1<<10));//PE10为低速输出 GPIOE->OSPEEDR &= (~(0x1<<10));//设置无上拉下拉GPIOE->PUPDR &= (~(0x3<<20));
//===============================================//设置PE9输出GPIOE->MODER &= (~(0x3<<18));GPIOE->MODER |= (0x1<<18);//设置PE10为推晚输出GPIOE->OTYPER &= (~(0x1<<18));//PE9为低速输出 GPIOE->OSPEEDR &= (~(0x1<<18));//设置无上拉下拉GPIOE->PUPDR &= (~(0x3<<18));
//===============================================//2.设置PB2\PG11用于UART4的管脚复用//PG11GPIOG->MODER &= (~(0x3 << 22));GPIOG->MODER |= (0x2 << 22);GPIOG->AFRH &= (~(0xf)<<12);GPIOG->AFRH |= (0x6<<12);//PB2GPIOB->MODER &= (~(0x3<<4));GPIOB->MODER |= (0x2<<4);GPIOB->AFRL &= (~(0xf)<<8);GPIOB->AFRL |= (0x1<<11);//3.0串口禁用USART4->CR1 &= (~0x1);//4.设置数据位宽为8位USART4->CR1 &= (~(0x1<<12));USART4->CR1 &= (~(0x1<<28));//5.设置无奇偶校验位USART4->CR1 &= (~(0x1<<10));//6.设置16倍过采样USART4->CR1 &= (~(0x1<<15));//7.设置1位停止位USART4->CR2 &= (~(0x3<<12));//8.设置不分频USART4->PRESC &= (~0xf);//9.设置波特率为115200USART4->BRR = 0x22B;//10.使能发送器USART4->CR1 |= (0x1<<3);//11.使能接收器USART4->CR1 |= (0x1<<2);//12.使能串口USART4->CR1 |= (0x1);
}void putchar(char a)
{//1.先判断发生器是否为空while (!(USART4->ISR & (0x1<<7)));//2.向发送寄存器写入数据USART4->TDR = a;//3.等待发送完成while(!(USART4->ISR & (0x1<<6)));
}char getchar()
{char a;//1.判断接收器是否有准备好的数据，没有就等待while (!(USART4->ISR & (0x1<<5)));//2.读取数据a = USART4->RDR;//3.返回return a;
}
//发送一个字符串
void puts(char *s)
{while(*s){putchar(*s);s++;}putchar('\r');putchar('\n');
}//接收一个字符串
void gets(char *s)
{while(1){*s=getchar();putchar(*s);//键盘输入的内容在串口上回显if(*s=='\r')break;s++;}*s='\0';putchar('\n');}int strcmp(char *src,char *dst)  //指令比较
{while(*src != '\0' && *dst != '\0'){if(*src != *dst){return *src - *dst;}src++;dst++;}if(*src == *dst){return 0;}else if(*src == '\0'){return *dst;}else if(*dst == '\0'){return *src;}}

uart4.h

#ifndef __UART4_H__
#define __UART4_H__
#include "stm32mp1xx_rcc.h"
#include "stm32mp1xx_gpio.h"
#include "stm32mp1xx_uart.h"void uart4_config();
void putchar(char a);
char getchar();
void puts(char *s);
void gets(char *s);
int strcmp(char *src,char *dst);#endif

main.c

#include"uart4.h"int main()
{//char a;char buf[128];uart4_config();while(1){/*//接收一个字符数据a = getchar();//发送 接收的字符+1putchar(a+1); putchar('\r');//回车，切换到一行开头putchar('\n');//切换到下一行   */puts("please enter order");gets(buf);if(strcmp(buf,"led_on") == 0){GPIOE->ODR |= (0x1<<10);}else if(strcmp(buf,"led_off") == 0){GPIOE->ODR &= (~(0x1<<10));}else if(strcmp(buf,"fen_on") == 0){GPIOE->ODR |= (0x1<<9);}else if(strcmp(buf,"fen_off") == 0){GPIOE->ODR &= (~(0x1<<9));}else{puts("puts error\n\r");}//puts(buf);  }
}

效果演示