设置按键中断，按键1按下，LED亮，再按一次，灭

按键2按下，蜂鸣器响。再按一次，不响

按键3按下，风扇转，再按一次，风扇停

keyit.h:

#ifndef __KEYIT_H__
#define __KEYIT_H__

#include "stm32mp1xx_rcc.h"
#include "stm32mp1xx_gpio.h"
#include "stm32mp1xx_exti.h"
#include "stm32mp1xx_gic.h"

void key_it_init();
void led_init();
void beep_init();
void fan_init();
#endif

keyit.c:

#include"keyit.h"

void key_it_init(){
	//RCC是能GPIOF时钟
	RCC->MP_AHB4ENSETR |= (0x1<<5);
	//设置PF9 PF7 PF8的GPIO输入模式
	GPIOF->MODER &= (~(0x3f<<14));
	//设置PF9 PF7 PF8产生EXTI事件
		//设置PF7
	EXTI->EXTICR2 &= (~(0xff<<24));
	EXTI->EXTICR2 |= (0x05<<24);
		//设置PF8,PF9
	EXTI->EXTICR3 &= (~(0xff));
	EXTI->EXTICR3 |= (0x05);
	EXTI->EXTICR3 &= (~(0xff<<8));
	EXTI->EXTICR3 |= (0x05<<8);
	//设置事件触发方式为下降沿触发
	EXTI->FTSR1 |= (0x7<<7);
	//设置EXTI事件触发不屏蔽
	EXTI->C1IMR1 |= (0x7<<7);

	//使能中断能转发到待定的CPU接口层
	GICD->ISENABLER[3] |= (0x7<<1);
	//设置中断优先级
		//设置按键1，PF9的优先级
	GICD->IPRIORITYR[24] &= (~(0x1f<<27));
		//设置按键2，PF7的优先级
	GICD->IPRIORITYR[24] &= (~(0x1f<<11));
		//设置按键3，PF8的优先级		
	GICD->IPRIORITYR[24] &= (~(0x1f<<19));
	//设置当前中断被转发到哪一个CPU处理
		//设置按键1对应中断处理程序由CPU0处理
	GICD->ITARGETSR[24] &= (~(0x3<<24));
	GICD->ITARGETSR[24] |= (0x1<<24);
		//设置按键2对应中断处理程序由CPU0处理
	GICD->ITARGETSR[24] &= (~(0x3<<8));
	GICD->ITARGETSR[24] |= (0x1<<8);
		//设置按键3对应中断处理程序由CPU0处理
	GICD->ITARGETSR[24] &= (~(0x3<<16));
	GICD->ITARGETSR[24] |= (0x1<<16);
	//使能组0转发中断
	GICD->CTRL |= 0x1;
	//设置中断优先级掩码
	GICC->PMR |= (0xf<<3);
	//使能CPU可以处理组0转发的中断
	GICC->CTRL |= (0x1);

}

void led_init(){
	//将gpioe和GPIOF的时钟使能
	RCC->MP_AHB4ENSETR |= (0x3<<4);
	//将三盏灯对应的gpio口的模式设置为输出
	GPIOE->MODER &= (~(0x3<<20));
	GPIOE->MODER |= (0x1<<20);
	GPIOF->MODER &= (~(0x3<<20));
	GPIOF->MODER |= (0x1<<20);
	GPIOE->MODER &= (~(0x3<<16));
	GPIOE->MODER |= (0x1<<16);

	//将输出模式设置为推挽输出
	GPIOE->MODER |= (0x1<<10);
	GPIOF->MODER |= (0x1<<10);
	GPIOE->MODER |= (0x1<<8);

	//将输出设置为低速
	GPIOE->OSPEEDR &= (~(0x3<<20));
	GPIOF->OSPEEDR &= (~(0x3<<20));
	GPIOE->OSPEEDR &= (~(0x3<<16));

	//设置无上拉下拉电阻
	GPIOE->PUPDR &= (~(0x3<<20));
	GPIOF->PUPDR &= (~(0x3<<20));
	GPIOE->PUPDR &= (~(0x3<<16));
}

void beep_init(){
	//将gpiob的时钟使能
	RCC->MP_AHB4ENSETR |= (0x1<<1);

	//讲蜂鸣器对应的PB6口的模式设置为输出模式
	GPIOB->MODER &= (~(0x3<<12));
	GPIOB->MODER |= (0x1<<12);

	//将输出模式设置为推挽输出
	GPIOB->MODER |= (0x1<<6);
	//讲输出设置为低速
	GPIOB->OSPEEDR &= (~(0x3<<12));
	//设置无上拉下拉电阻
	GPIOB->PUPDR &= (~(0x3<<12));
}

void fan_init(){
	//将gpiob的时钟使能
	RCC->MP_AHB4ENSETR |= (0x1<<4);

	//讲风扇对应的PE9口的模式设置为输出模式
	GPIOE->MODER &= (~(0x3<<18));
	GPIOE->MODER |= (0x1<<18);

	//将输出模式设置为推挽输出
	GPIOE->MODER |= (0x1<<9);
	//讲输出设置为低速
	GPIOE->OSPEEDR &= (~(0x3<<18));
	//设置无上拉下拉电阻
	GPIOE->PUPDR &= (~(0x3<<18));
}

do_irq.c:

//extern void printf(const char *fmt, ...);
#include "keyit.h"
void delay(int ms){
	for(int i=0; i<ms; i++){
		for(int j=0; j<2000; j++){}
	}
}
unsigned int flag_led = 0;
unsigned int flag_beep = 0;
unsigned int flag_fan = 0;
void do_irq(void) 
{
	int irqno;//保存中断号
	irqno = GICC->IAR&0x3FF;
	switch(irqno){
	case 99://key1
		//按键1中断处理
		if(flag_led==0){
			GPIOE->ODR |= (0x1<<10);
			GPIOF->ODR |= (0x1<<10);
			GPIOE->ODR |= (0x1<<8);
			flag_led = 1;
		}else{
			GPIOE->ODR &= (~(0x1<<10));
			GPIOF->ODR &= (~(0x1<<10));
			GPIOE->ODR &= (~(0x1<<8));
			flag_led = 0;
		}
		//清除挂起中断标志位
		GICD->ICPENDR[3] |= (0x1<<3);
		//清除中断触发标志位
		EXTI->FPR1 |= (0x1<<9);
		//清除处理完的中断号
		GICC->EOIR |= irqno;
		break;
	case 97://key2
		//按键2中断处理
		if(flag_beep==0){
			GPIOB->ODR |= (0x1<<6);
			flag_beep = 1;
		}else{
			GPIOB->ODR &= (~(0x1<<6));
			flag_beep = 0;
		}
		//清除挂起中断标志位
		GICD->ICPENDR[3] |= (0x1<<1);
		//清除中断触发标志位
		EXTI->FPR1 |= (0x1<<7);
		//清除处理完的中断号
		GICC->EOIR |= irqno;
		break;
	case 98://key3
		//按键3中断处理
		if(flag_fan==0){
			GPIOE->ODR |= (0x1<<9);
			flag_fan = 1;
		}else{
			GPIOE->ODR &= (~(0x1<<9));
			flag_fan = 0;
		}
		//清除挂起中断标志位
		GICD->ICPENDR[3] |= (0x1<<2);
		//清除中断触发标志位
		EXTI->FPR1 |= (0x1<<8);
		//清除处理完的中断号
		GICC->EOIR |= irqno;
		break;
	}

	
}

main.c:

#include"keyit.h"

int main()
{
	led_init();
	key_it_init();
	beep_init();
	fan_init();
	while(1){

	}
	return 0;
}

效果图：

LED：

风扇：

蜂鸣器无可见现象