！！！配置定时器的捕获引脚出现问题，中断没进去

主控板：TM4C1294NCPDT ,  编译坏境是：MDK

摄像头模块的频率是12MHZ

求大神指点，VSYNC用示波器测试频率是15hz，VSYNC作为触发中断
uint8_t OV_sta=0;//VSYNC帧同步信号
void Timer0_Init(void)
{
 /*****************°ÑPA0ÉèÖÃΪ²¶»ñÒý½Å*************************/
 SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
 SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
 GPIOPinTypeGPIOInput(GPIO_PORTA_BASE, GPIO_PIN_0);
 GPIOPinConfigure(GPIO_PA0_T0CCP0);
 GPIOPinTypeTimer(GPIO_PORTA_BASE, GPIO_PIN_0);
 TimerConfigure(GPIO_PORTA_BASE, TIMER_CFG_SPLIT_PAIR | TIMER_CFG_A_CAP_COUNT_UP);//¼Æʱ²¶»ñģʽ£¬ÉÏÉýÑز¶»ñ
 
 TimerControlEvent(TIMER0_BASE,TIMER_A,TIMER_EVENT_POS_EDGE);
 TimerMatchSet(TIMER0_BASE,TIMER_A,2);
 TimerLoadSet(TIMER0_BASE,TIMER_A,0);
 
 IntEnable(INT_TIMER0A);
// TimerIntEnable(TIMER0_BASE, TIMER_CAPA_EVENT);// ²¶»ñʼþ´¥·¢ÖжÏ
 TimerIntEnable(TIMER0_BASE, TIMER_CAPA_MATCH);
 IntMasterEnable();
 TimerEnable(TIMER0_BASE, TIMER_A);
// while(1)//¿ªÊ¼¼ÆÊý£¬µ±¼ÆÊýÖµµÈÓÚTimerLoadSet,´¥·¢ÖжÏ
// {

// }
}

/***************************************
|º¯ÊýÃû³Æ£ºvoid Timer0_IntHandler(void)
|¹¦ÄÜ£º´æÈ¡Êý¾ÝͼÏñÊý¾Ý
|ÊäÈë²ÎÊý£ºÎÞ
|Êä³ö²ÎÊý£ºÎÞ
***************************************/
void Timer0_IntHandler(void)
{
 //delay_Nms(50);//ÑÓʱ50ms//ÖжϺ¯Êý²»ÄܼÓÑÓʱº¯Êý
 //unsigned long ulStatus;
 OV_sta=TimerValueGet(TIMER0_BASE, TIMER_A);
 UART2_Putw_Dec(OV_sta);
// ulStatus = TimerIntStatus(TIMER0_BASE, true);//¶ÁÈ¡¶¨Ê±Æ÷ÖжÏ״̬
// TimerIntClear(TIMER0_BASE,ulStatus);//Çå³ýÖжÏ״̬ 
// TimerIntClear(TIMER0_BASE,TIMER_CAPA_EVENT);//Çå³ýÖжÏ״̬
 TimerIntClear(TIMER0_BASE,TIMER_CAPA_MATCH);
 if(OV_sta<2)
 {
  if(OV_sta==0)
  {
   OV7670_WRST0;//¸´Î»Ð´Ö¸Õë
   OV7670_WRST1;
   OV7670_WEN1;// ÔÊÐíдÈëFIFO
   
  }
  else
  {
   OV7670_WEN0;//½ûÖ¹FIFOдÈë
   OV7670_WRST0;
   OV7670_WRST1;
  }
  OV_sta++;
 }
}