请问具体操作，是在主函数中如何操作呢？尤其是关闭 外部中断，为什么每次开了外部中断后就关不上了。
void EXTIX_Init(void)
{
 
  EXTI_InitTypeDef EXTI_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;

  // KEY_Init(); 

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE); 


    GPIO_EXTILineConfig(GPIO_PortSourceGPIOE,GPIO_PinSource2);
 EXTI_ClearITPendingBit(EXTI_Line2); 

EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_InitStructure.EXTI_Line=EXTI_Line2; 
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
 
  EXTI_Init(&EXTI_InitStructure); 

 

    NVIC_InitStructure.NVIC_IRQChannel = EXTI2_IRQn; 
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02; 
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 
  NVIC_Init(&NVIC_InitStructure);


 
}