Path: utzoo!mnetor!uunet!husc6!bbn!rochester!PT.CS.CMU.EDU!SPEECH1.CS.CMU.EDU!phd
From: phd@SPEECH1.CS.CMU.EDU (Paul Dietz)
Newsgroups: sci.electronics
Subject: Re: Posting schematics...
Message-ID: <1269@PT.CS.CMU.EDU>
Date: 31 Mar 88 08:59:10 GMT
References: <1059@PT.CS.CMU.EDU> <1332@pasteur.Berkeley.Edu> <1213@cpocd2.UUCP> <1254@PT.CS.CMU.EDU> <1944@pasteur.Berkeley.Edu>
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Organization: Carnegie-Mellon University, CS/RI
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Keywords: schematics EDIF SPICE...

Max Hauser writes:
>Paul Dietz and several respondents seem to have the very specific idea of
>posting *pictures*, i.e., strictly-graphic information, incidentally about
>circuits. This of course requires a lot of data and an agreeable format.
>... consider that non-graphical
>schematics can encapsulate ALL of the real information a reader needs
>to reproduce the circuit...
>(As one dealing daily with circuit hacking for twenty years, I promise
>that it doesn't REALLY matter what direction the transistor points in,
>or whether that wire runs above or below, much as some people may have
>difficulty imagining a circuit not rendered in their favorite format).

On this point, I disagree with Max. The purpose of posting schematics
is mostly educational: the object is to make them understandable. Like
it or not, the way we draw things definitely influences our interpretation.
For this reason, I would like to see position information as an elemental
part of anything we do.

For instance, I can get a feel for a properly drawn 30 transistor op amp
in just a few seconds. If you handed me the netlist, it would probably
take me the better part of an hour before I had an equivalent understanding.

Circuit information comes in many forms: schematics, timing diagrams,
mask layouts, pcb's, flow charts, etc. An image representation has the
advantage of handling all of these equally well. As Max said:

>That was about circuits per se. Now I am the first to agree that it is
>also nice to communicate pictures of circuits (as long as we keep in mind
>that it is a different objective, with greater obstacles).

Now, just to prove my ability to do an about-face, I think Max is
absolutely correct in the need to keep our short term goals modest.
Circuits is ultimately what sci.electronics is all about! So for the
time being, I think a slightly modified SPICE type format will have to do.
The modifications are necessary to support rather arbitrary devices.
(SPICE doesn't know about things like uP's or the light bulbs in a
Wien Bridge...) This will serve two purposes: for circuits that can
easily be simulated by SPICE, we should stick to straight (or easily
machine translated to straight) SPICE files. I even volunteer to
write the C code to do the translation if it is easy enough!
For more random type circuits, when SPICE is not appropriate,
we will at least have a standard netlist format for various
programs to take advantage of.

So, let's have some discussion on this!

[By the way Max, your SPICE deck will make SPICE rather unhappy. Last
I heard, small letters are a no-no, along with no .END card, etc...
These are the sorts of things we should modify, to make it more
forgiving. As I said, I'm willing to write the C code to do this.]

Paul H. Dietz                                        ____          ____
Dept. of Electrical and Computer Engineering        / oo \        <_<\\\
Carnegie Mellon University                        /|  \/  |\        \\ \\
--------------------------------------------     | | (  ) | |       | ||\\
"If God had meant for penguins to fly,             -->--<--        / / |\\\  /
he would have given them wings."            _________^__^_________/ / / \\\\-