Re: switch debouncing



Spehro Pefhany wrote: 
On Mon, 17 Oct 2005 06:12:58 GMT, the renowned Mac <foo@xxxxxxx>
wrote:


Is there a standard or best way to de-bounce a switch?

After googling for a bit, this seems to be a good candidate:


        VCC
         |
         \
     R1  /
         \
         /
         |               Schmitt
         |            trig inverter
         |                |\
         +---/\/\/--+-----| >-- out
         |    R2    |     |/
     S1 \           = C
         |          |
        ---        ---
        GND        GND


R2 might be 18 k, and R1 82 k, with a 1uF cap as per this article:

http://www.embedded.com/showArticle.jhtml?articleID=18902552

Seems like it should work. Any comments?

--Mac


If it's going into a microcontroller, firmware is almost always the
best way.


Best regards, Spehro Pefhany

Well, if you can arrange things with external hardware so that the switch input is always valid, that is just that much less the firmware has to do- especially if the switch input is a very infrequent occurrence.

.

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