Alt-BEAM Archive
Message #12432
To: beam@sgiblab.sgi.com
From: "Wilf Rigter" Wilf.Rigter@powertech.bc.ca
Date: Fri, 24 Mar 2000 18:34:07 +1100
Subject: RE: Logic puzzle - I need to built a new gate... :-)
> Three components are needed as shown below:
>
> enjoy
>
> wilf
>
> <>
> > -----Original Message-----
> > From: Justin [SMTP:JAF60@student.canterbury.ac.nz]
> > Sent: Thursday, March 23, 2000 2:04 PM
> > To: beam@corp.sgi.com
> > Subject: Logic puzzle - I need to built a new gate... :-)
> >
> > Hiya,
> > For the turning system of a walker I'm designing, I ran into an engaging
> > logic problem that I thought I'd share will you (mainly in the hope that
> > someone could solve it in a more elegant manner than I have :-).
> >
> > The problem: (As illustrated below) I have a 4-state truth table and
> > want to build a circuit to give these outputs at the appropriate input.
> > It's easy if I use an XOR gate, but that would mean adding an entire
> > extra IC and I'll be trying to build small. My current solution when
> > freeformed would be slightly smaller than a chip, trouble is, it needs
> > adjusting when the voltage changes, and the voltage will change a lot
> > (solar walker) thus ruling out my design. I have no idea what the
> > circuit for an XOR gate is, and I think that could give someone who does
> > a big advantage.
> > The outputs are connected to the enable pins of a HC240, so that's the
> > kind of HIGH/LOW requirements the outputs have to meet.
> >
> > If someone could see a way to fix the sensitivity of my circuit, that
> > would also be great :-)
> >
> > Here is the guff: << File: puzzle1.gif >>
>
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