On Sun, 26 Apr 1998 16:32:05 -0600 Dwayne Reid writes: >Any other ideas on how I can speed this up even more? Use a timer interrupt for the timeout. Rather than return from the ISR, jump out to the timeout handler. The counter routine needs to be at the top-level (i.e. not a subroutine) so corrupting the stack by not returning from the interrupt doesn't cause problems. A similar approach uses a hardware interrupt caused by the pulse being measured to stop the counting. _____________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com Or call Juno at (800) 654-JUNO [654-5866]