Need help in RTC configuring to generate interrupt

I want to generate interrupt every 1.95ms., but it never hits ISR. Not sure what is the issue as i am quite new to LPC2378 programming. Can some one guide me.

When i put a breakpoint on ISR, it never hits it. Checked all the configuration in peripheral and vector options and all looks to be ok. Where am i doing mistake.

void rtc_tsr(void) __irq {

/* Reset the counter */ VICVectAddr = 0;
}

int main(void)
{ PCONP = 1 << 9; //RTC Power / clock control bit

RTC_CCR = 0x01; // To enable the timer counter

VICVectAddr13 = (unsigned long) rtc_tsr;

VICVectCntl4 = 0x02;

VICIntEnable = 1 << 13 ; // To enable interrupt from RTC source

RTC_CISS = 0x84; // To enable the Subsecond Interrupt & configure for 1.95ms delay

while(1);

return 0;
}