encoder knob inc/dec decoder revisited..

[Curtin, Steven D (Steven)]

> > >Now, I just need to try to get this thing down to 2 cmos chips so that
> > >it will have as little loading on an existing circuit as possible..I
> > >have changed it, so anyone interested in the fully tested circuit just
> > >email me..BTW, word about town is that the one-chip decoder (specialty
> > >item) is aprox 30 USD! This whole spiel cost me about 5 hrs of thinkin
> > >and tinkerin and about 3 dollars in parts..
> >
> > I wonder if anybody's considered doing this decoding with a PIC
> processor
> > chip. It'd be a dead simple program, one chip solution and could
> possibly
> > even use one of the tiny 8-pin PICs. If you used a bigger PIC with more
> I/O
> > pins you could do the decoding for multiple encoders. Just a thought...
> 
Another way to implement multiple encoders with a low chip count is with a
gate array or PLD.   This is how the input knobs on the Studer Editech
control surface were done.  This way you can also put some of the other
circuitry you're using the knobs to control right on the same chip.  Of
course these chips are more expensive, $80-$250 instead of $2, but they're
bristling with inputs and outputs.  The Philips cPLD I'm building a
sequencer/pattern generator around has 64 I/O pins and I've used them all up
already.

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Steven Curtin  
Lucent Technologies - Bell Labs Innovations
rm. 1A-229, 200 Laurel Ave S
Middletown, NJ 07748-4801  U S A
ph: (732)957-2996   fax: (732)957-6878
http://www.emf.org/subscribers/curtin/
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