Recently, Somebody Somewhere wrote these words
> You should be able to trap such pulses with a 74x121/123 monostable.
> Choose a time constant of several hundred ms and connect an LED to
> it or choose a time constant of some us and use your scope. The
> minimum trigger pulse length for the 74HC123 is 14-26ns.
>
> I once had a problem with a PAL (or was it a GAL) not doing what it
> was supposed to do and it was caused by bad filtering of the 5V supply
> voltage. I had to add an additional bypass capacitor close to the chip
> then it worked.
>
> Uwe.
You have even given me an idea on this... It took a second reading, but
that's good enough.
Build that circuit with a socket: Then, 74hc tests for the a pulse under
0.5 x power supply, whereas 74f or 74act tests for a pulse under ttl
levels.
--
With best Regards,
Declan Moriarty.
--
Author: Declan Moriarty
INET: [EMAIL PROTECTED]
Fat City Hosting, San Diego, California -- http://www.fatcity.com
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