Stm32 外部中断EXTI使用说明

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
        ...
    }
}