Re: gEDA-user: My first symbol...

["Phil Taylor" <phil@xxxxxxxxxxxxxxxxxxxxxxxx>]

KMK,

You might make your pins 300 units long, that's geda protocol.  Also, I would
try to extend your rail pins a little further out.  You'll find that when your
pins are larger, the entire symbol should be larger.

It's okay for pins to connect to lines, because once they're in the .sym file,
there is no meaningful 'connectivity' within the symbol itself.

I try to call _pinlabels_ things that cannot be confused with _pintype_ ...
such as Vo (Vout or Io or Iout) instead of 'out'.

If this is a specific part, with a specific package, you can add the footprint
to the symbol itself.  (or not depending on your religion).

Label your input pins exactly the way they are in the original manufacturer's
datasheet.  

Are you using a micro or all analog PID?

I don't have a clue what device vs. devicename is.  I just give device the
name of the part and ignore all devicename attributes.  This is bad because it
means your bom will later have part names in two categories: device and value
(sloppy).

Are you editing the symbol in gschem or in text?

If you're only sourcing _or_ sinking current to/from your peltier junction,
you might consider using a single mosfet and a little op-amp, or no op amp at
all if you're using a microcontroller.  This will give very good efficiency
and little heating on your pcb because the mosfet doesn't disspate any heat.

Phil




kmk <kmk@xxxxxxxxxxxxxxx> wrote:

> Hi all,
> 
> today I  am got serious with geda. My first project is a PID regulated
> peltier cooler. The output stage is going to be the power amp L165 which
> can drive up to 3A. The package of this component is of course non
> standard (pentawatt) with non standard pin numbers. So I decided to to
> define my first geda symbol by deriving it from single opamp symbol.
> 
> The single opamp symbols that came with the Debian package didn't meet
> the standard of the geda docs. I got lots of errors and warnings with
> gsymcheck, because they contain virtually no attribute. So I examined
> the docs a bit closer and came up with the attached symbol. Can you
> check whether I made mistakes or deviated from the geda standard?
> 
> There are two attributes, that I did not quite understand:
> What is the purpose of "device" and "devicename"? I guess, one of them
> should reflect the actual model that is supposed to enter the BOM. What
> about the other?
> 
> Thanks,
>        ---<(kaimartin)>---