Re: gEDA-user: Heavy Symbols and such

[Steve Meier <smeier@xxxxxxxxxxxxxxxxxxx>]

Hmmm well it would be nice if design rule checking had information about
the pins. Hooking an lvpecl output up to ttl input isn't going to work
very well. Even worse is switching the power and ground on an active
device. Is or should drc be part of gschem? Well to me gschem is just
one application that uses libgeda. Another application such as gnetlist
can run a drc set of rules against a design and it would be nice if
libgeda had access to more details about pin expectations (in, out,
in/out, logic family, max voltage, part of a differential pair?, if yes
to diff pair then is this the compliment of the pair or the standard?)
and on and on and on.

I am in agreement with the concept of a database conating all of this
and more and then the database application could generate symbols that
gschem could use and it could also be queeried for the additional info
that the drc or netlister could use.

In general I am in favior of of automated methods since they can get
smarter every year while I am very capable of making the same dumb
mistake over and over.

Steve Meier


DJ Delorie wrote:
>> Does gschem really has to know it's a "2-in AND" ?
>>     
>
> Well, to be pedantic, all it really needs to know is it uses a
> specific graphical symbol with pins at specific locations.
>
> But it wouldn't be much of a SCHEMATIC editor if it couldn't tell *us*
> that it's a 2-in AND gate.
>
>   
>> More specific: does gschem has a notion of the and function ?
>>     
>
> No, but that completely missed my point.  *If* the user puts a "2-in
> and" symbol in gschem, all gschem needs to know is that it's that
> symbol, with a given refdes.  Something else can correlate "that
> symbol" with a field in a database, mapping in part numbers, pinouts,
> and footprints, etc.
>
> The MEANING of the symbol is irrelevent to gschem, but the
> IDENTIFICATION as "that symbol" is relevent.  The symbol is to the
> class of part as the refdes is to the instance of the part.  The BOM
> maps an instance of a part to a member of the class of the part.
>
>   
>> And another one: does gschem fully grasp the "2-in" concept with
>> swapable pins ?
>>     
>
> Not directly.  I've built parts with "slots" for various input pin
> permutations.
>
>   
>> All gschem and pcb have in common is the refdes, pin info and
>> connectivity.
>>     
>
> Yup.  But they, as tools, wouldn't be useful to us if that was all
> they *could* deal with.
>
>
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>
>   



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