TMS320VC5509A RTC INTERRUPT

Dear Sir 

i am trying to get an interrupt from RTC module into an ISR but cant succed.

my code is  

RTC_IsrAddr rtc_Isr_addr={
	rtc_alarm_ISR,
	NULL,
	NULL
};

main{


	IRQ_setVecs((Uint32)(VECSTART));

rtc_enable();



}
void rtc_enable(void)
{
	rtc_EventID = RTC_getEventId();
	IRQ_clear(rtc_EventID);
//	RTC_setAlarm(&myAlarm);
	RTC_setPeriodicInterval(RTC_RATE_500ms);
    delay_1ms_onchip(1);    
	RTC_setCallback(&rtc_Isr_addr);
         
 //   IRQ_enable(rtc_EventID);          

	RTC_start();
	RTC_eventEnable(RTC_EVT_PERIODIC);
}

 void rtc_alarm_ISR(void)
{
	NOP;
	rtc_count++;
}

every thing seems o.k . but control is not coming to the break point inside ISR.please help.

Regards

Vikas