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设置按键中断，按键1按下，LED亮，再次按下，灭
按键2按下，蜂鸣器叫，再次按下，停
按键3按下，风扇转，再次按下，停

主函数：

linux@linux:~/study/08-c$ cat main.c 
#include "uart.h"
#include "key_it.h"
int main()
{char c;char *s;uart4_init();//串口初始化all_led_config();//灯泡初始化//中断初始化key_it_config();key3_it_config();while(1){//保证主程序不结束}return 0;
}

头文件：

linux@linux:~/study/08-c$ cat include/key_it.h 
#ifndef __KEY_IT_H__
#define __KEY_IT_H__
#include "stm32mp1xx_rcc.h"
#include "stm32mp1xx_gpio.h"
#include "stm32mp1xx_exti.h"
#include "stm32mp1xx_gic.h"void key_it_config();
void key3_it_config();
void all_led_config();#endif

初始化文件：

linux@linux:~/study/08-c$ cat src/key_it.c
#include"key_it.h"void all_led_config()
{//GPIOE时钟使能(*(unsigned int*)0X50000A28)  |= (0X1<<4);//PE10设置为输出模式*((unsigned int *)0X50006000) &= (~(0X3<<20));*((unsigned int *)0X50006000) |= (0X1<<20);//PB6设置为输出模式*((unsigned int *)0X50003000) &= (~(0X3<<12));*((unsigned int *)0X50003000) |= (0X1<<12);//PE9设置为输出模式*((unsigned int *)0X50006000) &= (~(0X3<<18));*((unsigned int *)0X50006000) |= (0X1<<18);//PE10设置为推挽输出*((unsigned int *)0X50006004) &= (~(0X1<<10));//PE9设置为推挽输出*((unsigned int *)0X50006004) &= (~(0X1<<9));//PB6设置为推挽输出*((unsigned int *)0X50003004) &= (~(0X1<<6));//PE10设置为低速输出*((unsigned int *)0X50006008) &= (~(0X3<<20));//PE9设置为低速输出*((unsigned int *)0X50006008) &= (~(0X3<<18));//PB6设置为低速输出*((unsigned int *)0X50003008) &= (~(0X3<<12));//PE10设置无上拉下拉电阻*((unsigned int *)0X5000600C) &= (~(0X3<<20));//PE9设置无上拉下拉电阻*((unsigned int *)0X5000600C) &= (~(0X3<<18));//PB6设置无上拉下拉电阻*((unsigned int *)0X5000300C) &= (~(0X3<<12));
}void key3_it_config()
{//RCC使能GPIOF时钟RCC->MP_AHB4ENSETR |= (0x1<<5);GPIOF->MODER &= (~(0x3<<16));EXTI->EXTICR3 &=(~(0xFF<<0));EXTI->EXTICR3 |= (0x5<<0);EXTI->FTSR1 |= (0x1<<8);EXTI->C1IMR1 |= (0x1<<8);GICD->ISENABLER[3] |= (0X1<<2); GICD->IPRIORITYR[24] &= (~(0X1F<<19)); GICD->ITARGETSR[24]  &= (~(0X3<<16));GICD->ITARGETSR[24] |= (0X1<<16);
}
void key_it_config()
{//RCC使能GPIOF时钟RCC->MP_AHB4ENSETR |= (0x1<<5);//设置PF9 PF7 PF8GPIO输入//PF9GPIOF->MODER &= (~(0x3<<18));//PF8// GPIOF->MODER &= (~(0x3<<16));//pf7GPIOF->MODER &= (~(0x3<<14));//设置PF9 PF7 PF8产生EXTI事件 EXTI_EXTICRx//pf7EXTI->EXTICR2 &=(~(0xFF<<24));EXTI->EXTICR2 |= (0x5<<24);//pf8// EXTI->EXTICR3 &=(~(0xFF<<0));// EXTI->EXTICR3 |= (0x5<<0);//pf9EXTI->EXTICR3 &=(~(0xFF<<8));EXTI->EXTICR3 |= (0x5<<8);//设置事件触发方式为下降沿触发EXTI_FTSR1//pf7EXTI->FTSR1 |= (0x1<<7);//pf8// EXTI->FTSR1 |= (0x1<<8);//pf9EXTI->FTSR1 |= (0x1<<9);//设置EXTI事件触发不屏蔽EXTI_IMR1//PF7EXTI->C1IMR1 |= (0x1<<7);//PF8// EXTI->C1IMR1 |= (0x1<<8);//PF9EXTI->C1IMR1 |= (0x1<<9);//使能中断能转发到特定的CPU接口层GICD_ISENABLERx//PF7 97号中断GICD->ISENABLER[3] |= (0X1<<1); //PF78 98号中断// GICD->ISENABLER[3] |= (0X1<<2); //PF9 99号中断GICD->ISENABLER[3] |= (0X1<<3); // GICD_ISENABLERx设置中断优先级//PF7GICD->IPRIORITYR[24] &= (~(0X1F<<11)); //PF8// GICD->IPRIORITYR[24] &= (~(0X1F<<19)); //PF9GICD->IPRIORITYR[24] &= (~(0X1F<<27)); //设置当前中断被转发到哪一个CPU处理GICD_ITARGETSRx//pf7 97中断GICD->ITARGETSR[24]  &= (~(0X3<<8));GICD->ITARGETSR[24] |= (0X1<<8);//pf8 98中断// GICD->ITARGETSR[24]  &= (~(0X3<<16));// GICD->ITARGETSR[24] |= (0X1<<16);//pf9 99中断GICD->ITARGETSR[24]  &= (~(0X3<<24));GICD->ITARGETSR[24] |= (0X1<<24);//使能组0转发中断GICD_CTLRGICD->CTRL |= 0X1;//设置中断优先级掩码GICC_PMRGICC->PMR |= (0x1F<<3);//使能CPU可以处理组0转发的中断GICC_CTLRGICC->CTRL |= 0X1;}

中断处理文件：

linux@linux:~/study/08-c$ cat src/do_irq.c
#include "key_it.h"
extern void printf(const char *fmt, ...);
unsigned int i = 0;
void do_irq(void)
{int irqno; // 保存中断号printf("%d\n",irqno);irqno = GICC->IAR & 0X3FF;switch (irqno){case 99: // key1// 按键1中断处理printf("KEY1 INT\n");*((unsigned int *)0X50006014) ^= (0X1<<10);// 清除挂起中断标志位GICD_ICPENDRxGICD->ICPENDR[3] |= (0x1 << 3);// 清除中断触发标志位EXTI_FPR1EXTI->FPR1 |= (0x1 << 9);break;case 97: // key2// 按键2中断处理printf("KEY2 INT\n");*((unsigned int *)0X50003014) ^= (0X1<<6);// 清除挂起中断标志位GICD_ICPENDRxGICD->ICPENDR[3] |= (0x1 << 1);// 清除中断触发标志位EXTI_FPR1EXTI->FPR1 |= (0x1 << 7);break;case 98: // key3// 按键3中断处理printf("KEY3 INT\n");*((unsigned int *)0X50006014) ^= (0X1<<9);// 清除挂起中断标志位GICD_ICPENDRxGICD->ICPENDR[3] |= (0x1 << 2);// 清除中断触发标志位EXTI_FPR1EXTI->FPR1 |= (0x1 << 8);break;}// 清除处理完的中断号GICC_EOIRGICC->EOIR = irqno;
}

效果图：