hi,
the need for a module to calculate seconds minutes and hours to use its calculations in other processes.
Do I miss something? From your posts I see that all you need are just 3 bytes in RAM for seconds, minutes and hours. So why do you not use a timer for such purpose as Erik has already suggested? Knowing crystal frequence, it is not hard to calculate its reload value and create simplest ISR which maintrains these bytes.

Regards,
Oleg