"Hermann, Erik" wrote:
>I want to use a 16C84 to measure the impulses from my Geiger-Mueller
>counter

This can work if the count rate is low.

Typical pulses from a Geiger-Mueller tube are narrow so you may want to
trigger an external flip-flop with the Geiger-Mueller pulse, poll the
flip-flop output and reset it if a pulse is detected.



If the rate is too high for simple polling, I would use a part that had
multiple timers such as a 16C62 and use one of the counters to count the
pulses directly.  You can then poll the counter from within your timer
interrupt routine.

I have used this technique in conjunction with a V/F converter and also
in a tachometer application.  Works like a champ.


--
Bob Fehrenbach     Wauwatosa, WI     bfehrenb@execpc.com