Re: gEDA-user: SPICE newbie -- was: Re: Simulation troubles ...

[Richard Rasker <rasker@xxxxxxxxxx>]

Op donderdag 08-11-2007 om 11:43 uur [tijdzone +0000], schreef Peter
Baxendale:
> Richard, I don't see a "file" attribute anywhere in your schematic to say
> where your spice model is. You can add a file attribute to each opamp
> symbol or add a spice directive symbol with the file attribute set
> to your spice model file. You should see the opamp subcircuit model
> included in the spice netlist.
> Also make sure the pinseq attributes of each pin in your opamp symbol
> match the order of the parameters to your spice model. In my
> experience the gschem opamp symbols usually need changing.

Ah, yes, that did the trick ... I did put both .sym files where gschem
could find them, in gEDA's spice symbol subdirectory (otherwise I
couldn't have selected the opamp in gschem in the first place) and
assumed that this would be enough. Which isn't the case, obviously.
And, of course, this *is* mentioned in the manual (albeit in a more
general manner).

But I think I'll compile all the good advice I got here into a sort
manual of my own, together with several step-by-step examples, and also
the mistakes I made and the points I had trouble with -- I'm pretty
certain that in a few months, I'll have forgotten one or more essential
steps. For me, the best way to learn new things is by means of clear and
detailed examples, with a manual to explain what exactly is happening
and why. Just a manual simply isn't enough for me, especially when there
are so many things that I can do wrong.

And perhaps if this manual of mine seems useful, I could post it online,
and/or offer it as an addition to the rest of the gEDA documentation.

> Also make sure the pinseq attributes of each pin in your opamp symbol
> match the order of the parameters to your spice model. In my
> experience the gschem opamp symbols usually need changing.

I literally copied Stuart Brorson's .sym files he posted on the mailing
list, and already double-checked the pinseq attributes; these were fine.

Anyway, I finally succeeded in simulating several filter configurations,
and these simulations indeed closely match the real-world results I got
from the circuits on my workbench :-)

Thanks again for the help, and I think I can manage on my own from here.

Best regards,

Richard Rasker



_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user