In a message dated 97-11-12 08:48:34 EST, you write: I was just wondering, don't ints occur every 200th of a sec regardless, and also doesn't the z80 processor operated on some kind of wave that occurs regularly. I remeber hearing about that. > 2. No. The speed of the calc depends on how good your batteries, so a > timer/watch is not possible. > > Dines