为什么我的外部中断函数不能进去

qianrushian 提问时间：2018-4-19 15:53 /

void LED_Init(void)
{

GPIO_InitTypeDef GPIO_InitStruct;
  EXTI_InitTypeDef  EXTI_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;

GPIO_InitStruct.GPIO_Pin =GPIO_Pin_0  ;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN;
GPIO_InitStruct.GPIO_PuPd=GPIO_PuPd_NOPULL;
GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
GPIO_Init(GPIOA, &GPIO_InitStruct);

EXTI_InitStructure.EXTI_Line = EXTI_Line0;
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure);
  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);

  NVIC_InitStructure.NVIC_IRQChannel = EXTI0_1_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}

void EXTI0_1_IRQHandler(void)//中断函数
{
if(EXTI_GetITStatus(EXTI_Line0)!= RESET )
   {
   SystemInit();
   EXTI_ClearITPendingBit(EXTI_Line0);
   }
}