Hi everyone,
i'm new at pic programming though i know basic logic of c and qbasic programming. i have a project that i have to calculate time between PORTA.0 and PORTA.1 inputs. (like i'm applying +5 volt for PORTA.0 and after 3ms apply +5 volt for PORTA.1). i dont have any problems about basic statements and loops and i need codes for; when PORTA.0=1 timer will start and it will end when PORTA.1=1 and 5ms would be enough for maximum value.
I've read about ON INTERRUPT and did not understand it well, and if there's no way around ON INTERRUPT i'd appreciate if you can explain it simple.

Thnx a lot.

i'm using XTAL 4 MHZ and pic16f84 but i can use other pics if i have to.