There's a real easy test for down-state bouncing.

What's nice about that algorithm is that it will only trigger once.  I've
used it in many projects and it never misses a key press, never triggers
more than once, and best of all, doesn't require any timers (h/w or s/w).
It just loops through, and after it pushes the 1 through, you get your key
press.

On 12/31/05, Wouter van Ooijen <wouter@voti.nl> wrote:
>
> > Best article I've ever read about Debouncing, and it has the
> > best algorithm I've ever seen as well.
> > http://ganssle.com/debouncing.pdf
>
> How is it better than just check every 50 ms?
>
> > > > This is fine if you're only worried about bouncing on
> > > > transitions.  If you
> > > > are doing filtering or the switch could bounce in one of the
> > > > states (like a
> > > > momentary pushbutton), then you need to sample faster and
> > > > apply debouncing
> > > > or filtering logic.
> > >
> > > This is new to me. You say a pushbutton (lika an ordinary
> > keyboard key)
> > > could bounce *while being pressed down*? And if so, how would you
> > > recognise such a bounce?
>
> The ganssle document is nice, but it does not mention down-state
> bouncing.
>
> Wouter van Ooijen
>
> -- -------------------------------------------
> Van Ooijen Technische Informatica: www.voti.nl
> consultancy, development, PICmicro products
> docent Hogeschool van Utrecht: www.voti.nl/hvu
>
>
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--


Shawn Wilton (b9 Systems)
http://black9.com
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