这是在stm32f10x_it..c中的设置
 
 void EXTI15_10_IRQHandler(void)
{        delay_ms(10);    //按键消抖       
                
     if(EXTI_GetITStatus(EXTI_Line14) != RESET)
        {          LCD_Clear(WHITE);
               LED2(0) ;
        }
 
     else if (EXTI_GetITStatus(EXTI_Line15) != RESET)
        {   LCD_Clear(BLACK);
            LED2(1) ;
         }
         EXTI_ClearITPendingBit(EXTI_Line14);  //清除EXTI13线路挂起位
         EXTI_ClearITPendingBit(EXTI_Line15);  //清除EXTI15线路挂起位                 
}
 
 
 
这是在exti.c中的设置
 
static void NVIC_Configuration(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;
  
  /* Configure one bit for preemption priority */
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
  
  /* 配置P[A|B|C|D|E]5为中断源 */
  NVIC_InitStructure.NVIC_IRQChannel = EXTI15_10_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}
 
 
void EXTI_Config(void)
{
        GPIO_InitTypeDef GPIO_InitStructure; 
        EXTI_InitTypeDef EXTI_InitStructure;
 
        /* config the extiline(PB0) clock and AFIO clock */
        RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO,ENABLE);
 
        /* config the NVIC(PB0) */
        NVIC_Configuration();
 
        /* EXTI line gpio config(PB0) */       
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_14|GPIO_Pin_15;       
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;         // 上拉输入
  GPIO_Init(GPIOA, &GPIO_InitStructure);
 
        /* EXTI line(PB0) mode config */
  GPIO_EXTILineConfig(GPIO_PortSourceGPIOA, GPIO_PinSource14|GPIO_PinSource15); 
  EXTI_InitStructure.EXTI_Line = EXTI_Line14|EXTI_Line15;
 
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling; //下降沿中断
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure); 
}
 
问题：
外部中断EXTI_LINE13进不去？EXTI_LINE15却能..为什么呀？请各位能人解释一下，不胜感激！

 EXTI_ClearITPendingBit(EXTI_Line14);  //清除EXTI13线路挂起位。这个地方写错了