2.串口发送指令控制硬件工作
结果：
uart.h
#ifndef __UART_H__
#define __UART_H__
#include "stm32mp1xx_gpio.h"
#include "stm32mp1xx_rcc.h"
#include "stm32mp1xx_uart.h"
void myuart4_init();
void myputchar(char i);
char mygetchar();
char *mygets();
void myputs(char *s);
void all_led_init();
void led1_on();
void led2_on();
void led3_on();
void led1_off();
void led2_off();
void led3_off();
int mystrcmp(char *ptr,char *str);
#endif
uart.c
#include "myuart.h"
char buf[100]={0};
//串口数据初始化
void myuart4_init()
{
//1.UART4和GPIOB\GPIOG的时钟使能
RCC->MP_AHB4ENSETR |= (0x1<<1);//使能GPIOB时钟
RCC->MP_AHB4ENSETR |= (0x1<<6);//使能GPIOG时钟
RCC->MP_APB1ENSETR |= (0X1<<16);//使能UART4时钟
//2.设置PB2和PG11的管脚复用
GPIOB->MODER&= (~(0x3<<4));
GPIOB->MODER|= (0x2<<4); //设置复用
GPIOB->AFRL &= (~(0XF<<8));
GPIOB->AFRL |= (0X8<<8);//设置uart4功能复用
GPIOG->MODER&= (~(0x3<<22));
GPIOG->MODER|= (0x2<<22); //设置复用
GPIOG->AFRH &= (~(0XF<<12));
GPIOG->AFRH |= (0X6<<12);//设置uart4功能复用
//3.先去设置串口禁用，方便设置数据格式
USART4->CR1 &= (~0X1);
//4.设置8位数据位
USART4->CR1 &=(~(0x1<<12));
USART4->CR1 &=(~(0x1<<28));
//5.设置没有奇偶校验
USART4->CR1 &=(~(0x1<<10));
//6.设置16倍采样
USART4->CR1 &=(~(0x1<<15));
//7.设置1位停止位
USART4->CR2 &=(~(0x3<<12));
//8.设置1分频
USART4->PRESC&=(~0xf);
//9.设置波特率为115200bps
USART4->BRR=0x22B;
//10.发送器、接收器使能
USART4->CR1|=(0X1<<3);
USART4->CR1|=(0X1<<2);
//11.串口使能
USART4->CR1|=(0X1);
}
//封装函数发送一个字符数据
void myputchar(char i)
{
//1.判断TDR寄存器是否为空，如果为空，向TDR寄存器写入数据
while(((USART4->ISR)&(0x1<<7))==0);
USART4->TDR=i;
//2.阻塞等待数据传输完成，函数返回
while(((USART4->ISR)&(0x1<<6))==0);
}
char mygetchar()
{
//判断RDR寄存器是否有就绪的数据，如果有就读取，否则等待
char a;
while(((USART4->ISR)&(0x1<<5))==0);
a=USART4->RDR;
return a;
}
void myputs(char *s)
{
while(*s)
{
myputchar(*s);
s++;
}
myputchar('\n');//切换到下一行
myputchar('\r');//切换到一行的开头
}
char *mygets()
{
unsigned int i=0;
for(i=0;i<100;i++)
{
buf[i]=mygetchar();
myputchar(buf[i]);
if(buf[i]=='\r')
break;
}
buf[i]='\0';
myputchar('\n');
return buf;
}
void all_led_init()
{
//1.使能外设时钟
RCC->MP_AHB4ENSETR |= (0x3<<4);
//2.设置PF10 PE10 PE8为输出输出
GPIOE->MODER&= (~(0x3<<20));
GPIOE->MODER|= (0x1<<20);
GPIOF->MODER&= (~(0x3<<20));
GPIOF->MODER|= (0x1<<20);
GPIOE->MODER &= (~(0x3<<16));
GPIOE->MODER|= (0x1<<16);
//3.设置推挽输出
GPIOE->OTYPER &= (~(0x1<<10));
GPIOF->OTYPER &= (~(0x1<<10));
GPIOE->OTYPER &= (~(0x1<<8));
//4.设置输出速度为低速
GPIOE->OSPEEDR &= (~(0x3<<20));
GPIOF->OSPEEDR &= (~(0x3<<20));
GPIOE->OSPEEDR &= (~(0x3<<16));
//5.设置无上拉下拉
GPIOE->PUPDR &= (~(0x3<<20));
GPIOF->PUPDR &= (~(0x3<<20));
GPIOE->PUPDR &= (~(0x3<<16));
}
void led1_on()
{
GPIOE->ODR |= (0x1<<10);
}
void led2_on()
{
GPIOF->ODR |= (0x1<<10);
}
void led3_on()
{
GPIOE->ODR |= (0x1<<8);
}
void led1_off()
{
GPIOE->ODR&= (~(0x1<<10));
}
void led2_off()
{
GPIOF->ODR &= (~(0x1<<10));
}
void led3_off()
{
GPIOE->ODR &= (~(0x1<<8));
}
int mystrcmp(char *ptr,char *str)
{
while(*ptr)
{
if(*ptr!=*str)
return -1;
ptr++;
str++;
}
return 0;
}
main.c
#include "myuart.h"
int main()
{
myuart4_init();
all_led_init();
char *buf;
while(1)
{
myputchar('\n');
myputchar('\r');
buf=mygets();
if(mystrcmp(buf,"led1_on")==0)
led1_on();
else if(mystrcmp(buf,"led1_off")==0)
led1_off();
else if(!mystrcmp(buf,"led2_on"))
led2_on();
else if(!mystrcmp(buf,"led2_off"))
led2_off();
else if(mystrcmp(buf,"led3_on")==0)
led3_on();
else if(mystrcmp(buf,"led3_off")==0)
led3_off();
}
return 0;
}