Hi Rauf,

to reload the timer with a constant give always inaccurate timings, which can be tolerated only to sound a buzzer or flashing a LED.

On a RTC application you must always regard the interrupt response time, which can be different by many reasons (look at the data sheet).

But its easy to watch it, since the timer continue running after setting the interrupt flag. So itself contain the exact interrupt response time. And if you add the count of cycles, which you want to be faster, you get always exact the same and high precise time delay.
Especially on using other interrupts, this was important.

Please look at the example:
http://www.specs.de/~danni/ap.../index.htm


Peter


Peter