gEDA-user: gEDA 1.2.0, opamp-1.sym pin numbers?

[Peter TB Brett]

On Sunday 23 September 2007 15:40:42 Dan McMahill wrote:
> Peter Clifton wrote:
> > On Sat, 2007-09-22 at 20:35 +0200, Stefan Salewski wrote:
> >> I think that opamp-1.sym will not be compatible with SOT23-5 footprints
> >> -- in TI datasheet of OPA656 pin 1 is output for SOT23 package. Maybe
> >> opamp-1.sym is compatible with SC70-5 configuration, which I have newer
> >> seen.
> >>
> >> Or opamp-1.sym and opamp-2.sym are only abstract representations of an
> >> OpAmp, without any relationship to a concrete footprint?
> >>
> >> In any case, there seems to be no symbol in gEDA related to an ordinary
> >> OpAmp in DIP8 (or SO8) package.
> >>
> >> This may look very strange for new gEDA/pcb users.
> >
> > There are various "heavy" symbols, such as lm741-1.sym.
> >
> > It is a well known problem though, the mapping between a light symbol
> > and a real package is not something which is easily solved.
>
> which is why I'm in favor of a heavy symbol generator for op-amps like
> the one I demonstrated for bipolar transistors.  You use a small set of
> symbols and then have a text file which is essentially a spread sheet
> that for each actual part number (the full vendor part number including
> package code) you give the mapping from symbol pin to the footprint pin
> # as well as list the actual footprint.  Its pretty simple, you don't
> have to continually wonder if you have the right footprint or right
> pinout, and you only have to maintain a small number of graphical
> symbols.  Adding new part number is then a snap.

You could write a script which does this and exposes the results as a library 
in gschem.  You wouldn't need to actually generate the on-disc files then; 
you could create the library on-demand from symbol + spreadsheet.

(What you're suggesting is exactly what I had in mind when I did the rework of 
the libgeda library mechanism).

Peter
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