Paul,

Thanks for making this public - since I've not found a lot of information on
this topic. By the way, for whoever's listening, I usually peruse the
archives before I bother you all with a question. I've found the archives an
invaluable font of information and I appreciate your contributions.

[Some of my/yours stuff snipped for brevity]

> It's a concept thing.  A PIC is a cheap device to "do things".  It is
> intended to reduce designs to the absolute minimum of parts.  Using an
> IC to pre-process data *for* the PIC is very much against the grain if
> the PIC can do it for itself, and switch de-bouncing is a perfect
> example.
>
>   I'd go for Andy's proposal.  If nothing else (and there is nothing
> else), he knows his stuff.  My summary:

This is my attitude as well. I'd rather do in software what can also be done
in hardware and with this concept I'm noodling with, I'd rather keep my chip
count low. However, if hardware means significantly more reliability, I'll
investigate it.

Amen on you guys know your stuff. I'm hardware handicapped. By the way, what
do those little colored bands on those resistor thingies mean? (joke,
sorry - I felt that some of the barbs tossed about today were directed at
people like me).

>  * Forget switch parameters (exception: it's not a pushbutton but a
> sensor e.g.; opto-interrupter, contact on assembly etc.).  You can't
> physically actuate a pushbutton more than ten times per second and
> almost certainly don't want to be able to, so the debounce cycle need be
> no shorter than 50mS.  So make it 50mS!

Agreed. There are no fingers fast enough and I can easily set "rules" for
user-supplied switches.

As for the switch parameter point of view, it seemed like the obvious thing
to do. Well, that is from a business application point of view. You know,
stuff things in databases and variables because you can.... I need to work
on my PIC frugality - although with a 17-series chip, you can build a house
in those things.

> This refers to the NAND gate R-S flipflop with a SPDT switch?  Care to
> elaborate?

Yes. Remembered the concept from a class long ago and while it uses a SPDT,
I wondered if hardware was a better approach. I'd like to keep all my
buttons as SPST NO. You (and Andy) confirmed that software may be the best
route.

>   Cheers,
>         Paul B.

I have an office in Melbourne and Sydney - I realize that your neighborhood
is rather large but....

-DO