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From: wetter@tybalt.caltech.edu (Pierce T. Wetter)
Newsgroups: comp.sys.mac
Subject: Re: EXACT screen refresh rate, and other items
Message-ID: <2895@cit-vax.Caltech.Edu>
Date: Mon, 1-Jun-87 20:47:19 EDT
Article-I.D.: cit-vax.2895
Posted: Mon Jun  1 20:47:19 1987
Date-Received: Wed, 3-Jun-87 03:46:34 EDT
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Reply-To: wetter@tybalt.caltech.edu.UUCP (Pierce T. Wetter)
Organization: Calfornia Institute of Technology
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>
>	I don't have my mac yet, nor IM, nor schematics, so this might
>be a dumb question, but - hardware switch debouncing circuits have been
>around for longer than micros. You can make one with part of a real
>dumb chip. Why does Apple use/need software to debounce the switch ??

    One thing that de-bouncing chips require is a debounce clock. Debouncer 
chips work by remembering if the input lines have been toggled in the last
x clock periods - about what the software does. Personally I'm not
surprised they didn't put one in just for debouncing the mouse. 
   Pierce Wetter

The USA is so enormous, and so numerous are its schools, colleges and
religious seminaries, many devoted to special religious beliefs ranging
from the unorthodox to the dotty, that we can hardly wonder at its
yielding a more bounteous harvest of gobbledygook than the rest of the
world put together.
		-- Sir Peter Medawar

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wetter@tybalt.caltech.edu

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