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From: dale@lamont.ldgo.columbia.edu (dale chayes)
Newsgroups: sci.electronics
Subject: Address decoders continued...
Keywords: decoders
Message-ID: <2848@lamont.ldgo.columbia.edu>
Date: 10 Oct 90 21:48:42 GMT
Organization: Lamont-Doherty Geological Observatory N.Y.
Lines: 19


An 8-bit decoder based on  a '688 requires three "chips", the
688, a (half of a) package of pull-up resistors and the dip switch. 
If you don't need the  user selectablility of the dip switches and 
have already made the leap to programable logic, you can do a single chip 
solution with almost any PAL. I prefer GALs (Generic Array Logic) 
myself mostly because of the easy re-programming (I never seem to have
time to get it right the first time, but usualy have time to get it
right eventually.)

A nice feature of the GAL(PAL) solution, is that you have lots of 
flexibility about signal polarity and you can clock it if that is 
appropriate.

Dale
-- 
Dale Chayes Lamont-Doherty Geological Observatory of Columbia University
Route 9W, Palisades, N.Y.  10964	dale@lamont.ldgo.columbia.edu
voice:	(914) 359-2900 extension 434	fax: (914) 359-6817