gEDA-user: 1.) Feedback, 2.) gschem->gnetlist->ngspice question(s)

[Ales Hvezda <ahvezda@moria.seul.org>]

[ Ales here, I'm reposting this since majordomo didn't recognize the
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-- Cut here --
From: Felix <schmitt@voidcast.de>

Hi everyone,

1.) Feedback:
I am brand new to this project.
Worked with freeware version of "pspice" (20 parts limit) under win before, 
but wanted to have sth. that works with my favorite operating system :-)
System:
    gentoo, geda build 20040111
First impression:
    - gschem looks nice, is intuitive to work with. I like it.
      (Is there any way to scroll the view with the cursor keys?)
    - geda does not work properly, produces gtk errors
      (I can send the details if wanted)
    - gnetlist did not work properly. Wasn't able to use spice.

2.) gschem->gnetlist->ngspice question(s):
My goal was to simulate a very simple switching power supply via the design 
flow gschem->gnetlist->ngspice. The layout roughly looks like this:

                 +----------------+
                 |                |
Vref ------------|(-)             |
                 |    OP_AMP (OUT)|----+-----+----- Vout
Vin  --\/\/\--+--|(+)   U1        |    |     |
         R1   |  |                |    |   =====
              |  +----------------+    |   ===== C1
              |                        |     |
              +---------\/\/\----------+     |
                          R2               -----
                                            --- GND
                                             -

(In pspice, this wouldn't be a problem.)
I couln't get this through gnetlist.
Then, I spent two days reading man pages/usage info. That did not help much.
Any ideas?
My guess is, that ngspice can only handle "basic" parts like R,C,L,Transistors 
in different flavors, etc., and gnetlist is not able (yet) to generate the 
apropriate hierarchical code or whatever to feed into ngspice, and therefore 
just coughs up when hitting the opamp part.
Therefore my questions:
a.) Not all .sym models in /usr/share/gEDA/syms/* make it through gnetlist, 
right?
b.) Do you have a list of symbols that pass the gnetlist->spice-sdb process? 
Is it possibly the "gEDA symbol library" I find on Your homepage? How do I 
read it? (the legend did not help me very much :-( )
c.) Wouldn't it be nice to have a tool with which you could generate SPICE 
code for new parts in the following manner: 
I) You click the parts together out of which this new part consists 
(graphical)
II) You have this new part simulated in standard testing setups and get graphs 
and specs from the simulation (automated, graphical)
III) You can adjust the different parameters of the "atomic" parts and repeat 
step II in order to match the data sheets you downloaded from the 
manufacturer to your sim data.
IV) the .MODEL or .SUBCKT file is then included into the .sym model file in 
some fashion.
I think gEDA does have much potential (I like it already). I would like to 
work on a program that does things like the above-mentioned, if there would 
be interest and use for it in the gEDA project. (can do c, perl, etc., cannot 
do guile, python (yet))

This is a long posting. If you got up to here, thanks for taking the time to 
read it :-)
I appreciate any help!

Thanks

Felix.