STM32入门学习之外部中断

1.STM32的IO口可以作为外部中断输入口。本文通过按键按下作为外部中断的输入，点亮LED灯。在STM32的19个外部中断中，0-15为外部IO口的中断输入口。STM32的引脚分别对应着0-15的外部中断线。比如，外部中断线0对应着GPIOA.0-GPIOG.0，以此类推就可以将所以的IO映射到0-15个外部中断线上。STM32的IO的外部中断映射图如下：

 2.外部中断的配置步骤：

（1）将IO口映射到对应的外部中断线上，中断线河中断初始化。

（2）配置外部中断，即配置中断管理NVIC。

 （3）重写中断服务函数，即中断回调函数。这些中断回调函数在startup_stm32f10x_xx.s中被规定好了名称，我们只需要重写对应的中断回调函数即可。

3.工程代码：

delay.h:

#ifndef __DELAY_H
#define __DELAY_H#include "stm32f10x.h"void delay_us(uint32_t us);									//ÑÓʱ΢Ãë
void delay_ms(uint32_t ms);									//ÑÓʱºÁÃë#endif

delay.c:

#include "delay.h"void delay_us(uint32_t us)
{uint32_t i;//1.Ñ¡ÔñHCLKʱÖÓ£¬²¢ÉèÖõδðʱÖÓ¼ÆÊýÖµSysTick_Config(72);for(i = 0;i < us;i++){while(!((SysTick->CTRL) & (1 << 16)));		//µÈ´ý¼ÆÊýÍê³É}SysTick->CTRL &= ~SysTick_CTRL_ENABLE_Msk;	//Ñ¡ÔñSTCLKʱÖÓÔ´£¬²¢Ê§Äܶ¨Ê±Æ÷
}void delay_ms(uint32_t ms)
{uint32_t i;//1.Ñ¡ÔñHCLKʱÖÓÔ´£¬²¢ÉèÖõδðʱÖÓ¼ÆÊýÖµSysTick_Config(72000);for(i = 0;i < ms;i++){while(!((SysTick->CTRL) & (1 << 16)));		//µÈ´ý¼ÆÊýÍê³É}SysTick->CTRL &= ~SysTick_CTRL_ENABLE_Msk;	//Ñ¡ÔñSTCLKʱÖÓÔ´£¬²¢Ê§Äܶ¨Ê±Æ÷
}

key.h:

#ifndef __KEY_H
#define __KEY_H#include "stm32f10x.h"#define KEY_0 GPIO_ReadInputDataBit(GPIOC,GPIO_Pin_5)			//¶ÁÈ¡°´¼üµÄ״̬
#define KEY_1 GPIO_ReadInputDataBit(GPIOA,GPIO_Pin_15)
#define KEY_2 GPIO_ReadInputDataBit(GPIOA,GPIO_Pin_0)void KEY_Init(void);
void KEY_Scan(void);						//°´¼üɨÃ躯Êý#endif

key.c:

#include "key.h"
#include "delay.h"
#include "led.h"void KEY_Init(void)
{/*1.¶¨ÒåÒý½ÅµÄ½á¹¹Ìå¡£2.ʹÄÜÒý½Å¶ÔÓ¦µÄʱÖÓ¡£3.ÅäÖÃÒý½ÅÐÅÏ¢*///¶¨ÒåÒý½Å½á¹¹Ì壺GPIO_InitTypeDef GPIO_InitStruct;//ʹÄÜʱÖÓ£ºRCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOC,ENABLE);//ÅäÖÃÒý½ÅÐÅÏ¢(KEY0)£ºGPIO_InitStruct.GPIO_Pin = GPIO_Pin_5;GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IPU;GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOC,&GPIO_InitStruct);//ÅäÖÃKEY1£ºGPIO_InitStruct.GPIO_Pin = GPIO_Pin_15;GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IPU; //ÉèÖóÉÉÏÀ­ÊäÈëGPIO_Init(GPIOA,&GPIO_InitStruct);//ÅäÖð´¼üWK_UP:GPIO_InitStruct.GPIO_Pin = GPIO_Pin_0;GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IPD;GPIO_Init(GPIOA,&GPIO_InitStruct);LED_Init();									//³õʼ»¯LED
}void KEY_Scan(void)
{static u8 key_up = 1;				//°´¼üËÉ¿ª±ê־λif(key_up && (KEY_0 == 0||  KEY_1  == 0|| KEY_1 == 1)){delay_ms(10);						  //È¥¶¶¶¯key_up = 0;if(KEY_0 == 0){GPIO_ResetBits(GPIOD ,GPIO_Pin_2);GPIO_SetBits(GPIOA,GPIO_Pin_8);//delay_ms(1000);}else if(KEY_1 == 0){GPIO_ResetBits(GPIOA ,GPIO_Pin_8);GPIO_SetBits(GPIOD,GPIO_Pin_2);//delay_ms(1000);}else if(KEY_2 == 1){GPIO_ResetBits(GPIOA ,GPIO_Pin_8);GPIO_ResetBits(GPIOD ,GPIO_Pin_2);}}else if(KEY_0==1&&KEY_1==1&&KEY_2==0){key_up = 1;}
}

exti.h:

#ifndef __EXTI_H
#define __EXTI_H#include "stm32f10x.h"void EXTIx_Init(void);#endif

exti.c:

#include "exti.h"
#include "key.h"
#include "delay.h"void EXTIx_Init(void)
{/*ÍⲿÖжϵÄÅäÖ÷½·¨£º1.½«IO¿ÚÓ³Éäµ½¶ÔÓ¦ÍⲿÖжÏÏßÉÏ2.ÅäÖÃÍⲿÖжÏ3.ÖØдÖжϷþÎñº¯Êý£¬¼´Öжϻص÷º¯Êý*///¶¨ÒåÍⲿÖжϺÍÖжϵĽṹÌ壺EXTI_InitTypeDef EXTI_InitStructure;NVIC_InitTypeDef NVIC_InitStructure;//ʹÄÜʱÖÓ£ºRCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);//ÍⲿÖжÏÐèÒª¸´ÓÃʱÖÓKEY_Init();			//³õʼ»¯°´¼ü//GPIOC.5µÄÖжÏÏߺÍÖжϳõʼ»¯ÅäÖãºGPIO_EXTILineConfig(GPIO_PortSourceGPIOC,GPIO_PinSource5);	//GPIOÓëÖжÏÏß½øÐÐÓ³ÉäEXTI_InitStructure.EXTI_Line = EXTI_Line5;EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;EXTI_InitStructure.EXTI_LineCmd = ENABLE;EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising_Falling;EXTI_Init(&EXTI_InitStructure);//½«ÉÏÃæÅäÖõÄÐÅϢдÈëEXTI¼Ä´æÆ÷ÖÐ//GPIOA.0µÄÖжÏÏߺÍÖжϳõʼ»¯ÅäÖãºGPIO_EXTILineConfig(GPIO_PortSourceGPIOA,GPIO_PinSource0);	//GPIOÓëÖжÏÏß½øÐÐÓ³ÉäEXTI_InitStructure.EXTI_Line = EXTI_Line0;EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;EXTI_InitStructure.EXTI_LineCmd = ENABLE;EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;EXTI_Init(&EXTI_InitStructure);//GPIOA.15µÄÖжÏÏߺÍÖжϳõʼ»¯ÅäÖãºGPIO_EXTILineConfig(GPIO_PortSourceGPIOA,GPIO_PinSource15);	//GPIOÓëÖжÏÏß½øÐÐÓ³ÉäEXTI_InitStructure.EXTI_Line = EXTI_Line15;EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;EXTI_InitStructure.EXTI_LineCmd = ENABLE;EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;EXTI_Init(&EXTI_InitStructure);//ÖжϹÜÀíÅäÖãºNVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;NVIC_Init(&NVIC_InitStructure);NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQn;NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;NVIC_Init(&NVIC_InitStructure);NVIC_InitStructure.NVIC_IRQChannel = EXTI15_10_IRQn;NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;NVIC_Init(&NVIC_InitStructure);	
}//ÖØдÖжϷþÎñº¯Êý.
void EXTI0_IRQHandlÕâЩÖжϻص÷º¯ÊýÔÚstartup_stm32f10x_xx.sÖб»¹æ¶¨ºÃÁËÃû³Æer(void)
{//¾²Ì¬±äÁ¿Ö»»áÔÚµÚÒ»´ÎÔËÐÐʱ±»³õʼ»¯¡£ËùÒÔ£¬¿ÉÒÔÀí½âΪÕâÌõÓï¾äÖ»Ö´ÐÐÒ»´Îstatic u8 flag1 = 1;	delay_ms(10);				//Ïû¶¶if(KEY_2 == 1){if(flag1){//GPIO_ResetBits(GPIOD ,GPIO_Pin_2);GPIO_SetBits(GPIOA,GPIO_Pin_8);flag1 = !flag1;}else{GPIO_ResetBits(GPIOA ,GPIO_Pin_8);//GPIO_SetBits(GPIOD,GPIO_Pin_2);flag1 = !flag1;}}EXTI_ClearITPendingBit(EXTI_Line0);
}void EXTI9_5_IRQHandler(void)
{static u8 flag2 = 1;delay_ms(10);				//Ïû¶¶if(KEY_0 == 0){if(flag2){//GPIO_ResetBits(GPIOA,GPIO_Pin_8);GPIO_SetBits(GPIOD,GPIO_Pin_2);flag2 = !flag2;}else{//GPIO_ResetBits(GPIOA,GPIO_Pin_8);GPIO_ResetBits(GPIOD,GPIO_Pin_2);flag2 = !flag2;}}EXTI_ClearITPendingBit(EXTI_Line5);
}void EXTI15_10_IRQHandler(void)
{static u8 flag3 = 1;delay_ms(10);				//Ïû¶¶if(KEY_1 == 0){if(flag3){GPIO_ResetBits(GPIOA,GPIO_Pin_8);GPIO_ResetBits(GPIOD,GPIO_Pin_2);flag3 = !flag3;}else{GPIO_SetBits(GPIOA,GPIO_Pin_8);GPIO_SetBits(GPIOD,GPIO_Pin_2);flag3 = !flag3;}}EXTI_ClearITPendingBit(EXTI_Line15);
}

main.c:

#include "stm32f10x.h"
#include "delay.h"
#include "led.h"
#include "key.h"
#include "exti.h"int main(void)
{//LED_Init();NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);// ÉèÖÃÖжÏÓÅÏȼ¶·Ö×é2KEY_Init();EXTIx_Init();while(1){
//		GPIO_ResetBits(GPIOD ,GPIO_Pin_2);
//		GPIO_SetBits(GPIOA,GPIO_Pin_8);
//		delay_ms(1000);
//		GPIO_ResetBits(GPIOA ,GPIO_Pin_8);
//		GPIO_SetBits(GPIOD,GPIO_Pin_2);
//		delay_ms(1000);//KEY_Scan();}
}

4.运行结果：按下key0，LED1亮，再按一下熄灭。按下key1，LED0亮，再按一下熄灭。按下key3，两个LED亮，再按一下两个LED熄灭。

 

 

 

 5.总结：本文是通过key的外部中断来控制led的亮灭。其原理是利用STM32的IO可作为外部中断的输入口。当按下key时，对应的IO空作为输入会触发外部中断，然后系统会去调用对应的外部中断服务函数。通过中断，可以不用阻塞程序，在中断未被触发时，程序可以去执行其他的工作，提高系统的效率。

在配置外部中断的相关信息时，主要是配置相关的结构体信息、将IO映射到对应的中断线、配置中断管理NVIC。