I am still having trouble understanding the timer interupt on the 16f73 and how to use it. whatvariable holds the value for the timer? basically i think all i need is something as simple as this follow psuedo code idea.

while tmr0 is less then 500ms 'tmr0 counts in the background regaurless of pauses.
gosub ramp
if trigger pulled reset tmr0
wend