STM32外部中断EXTI学习笔记

硬件情况：采用PA11管脚

需要明确的是，PxN管脚共用外部中断线EXTIN和外部中断向量EXTIN_IRQn和中断服务程序入口EXTIN_IRQHandler，但是需要注意的是[9…5]共用EXTI9_5_IRQn和EXTI9_5_IRQHandler、[15…10]共用EXTI15_10_IRQn和EXTI15_10_IRQHandler

基本过程：

1、设置时钟

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE); 

注意需要打开AFIO时钟

2、配置GPIO

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;  

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;  

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;  

GPIO_Init(GPIOA, &GPIO_InitStructure);  

采用浮空输入方式

3、将GPIO管脚与外部中断线连接

GPIO_EXTILineConfig(GPIO_PortSourceGPIOA, GPIO_PinSource11);  

相当重要

4、配置EXTI

EXTI_InitStructure.EXTI_Line = EXTI_Line11;  

EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;  

EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;  

EXTI_InitStructure.EXTI_LineCmd = ENABLE;  

EXTI_Init(&EXTI_InitStructure);  

包括触发方式等等

6、配置NVIC

NVIC_InitTypeDef NVIC_InitStructure;      

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);  

NVIC_InitStructure.NVIC_IRQChannel = EXTI15_10_IRQn; //PPP外部中断线  

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;  

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;  

NVIC_Init(&NVIC_InitStructure);  

7、写中断服务程序

void EXTI15_10_IRQHandler(void)  

{  

    if (EXTI_GetITStatus(EXTI_Line11) != RESET)  

    {  

        EXTI_ClearITPendingBit(EXTI_Line11);//清除标志  

        ...  

    }  

}