STM32的外部中断配置及使用
配置1：GPIO；
配置外部中断为输入模式；
配置2：EXTI；
配置外部中断线和触发模式；
配置3：NVIC；
配置外部中断源和中断优先级；
需要注意的是：RCC_APB2Periph_AFIO 时钟必须打开，容易忽略的一点；
void EXTI_PORTC_CONFIG(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
EXTI_InitTypeDef EXTI_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure; RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC|RCC_APB2Periph_AFIO,ENABLE); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU ; //内部上拉
GPIO_Init(GPIOC, &GPIO_InitStructure); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU ; //内部上拉
GPIO_Init(GPIOC, &GPIO_InitStructure); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU ; //内部上拉
GPIO_Init(GPIOC, &GPIO_InitStructure); GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource2);
GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource3);
GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource5); EXTI_InitStructure.EXTI_Line = EXTI_Line2;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure); EXTI_InitStructure.EXTI_Line = EXTI_Line3;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure); EXTI_InitStructure.EXTI_Line = EXTI_Line5;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure); NVIC_InitStructure.NVIC_IRQChannel = EXTI2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = ;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = ;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure); NVIC_InitStructure.NVIC_IRQChannel = EXTI3_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = ;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = ;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure); NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = ;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = ;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}