Re: gEDA-user: Matching footprints with symbols

[Kai-Martin Knaak <kmk@xxxxxxxxxxxxxxx>]

On Wed, 14 Apr 2010 18:41:44 +0200, Amand Tihon wrote:

> It could be due to my distribution (Debian), but I always get lost in
> the symbols and footprints libraries that come with gEDA. Finding the
> right footprint with correct pin numbering has always been a challenge.

You are not the only one. This is consequence of a number of unresolved 
issues:

1) Unlike other EDA applications, there is no notion of a "package" that 
contains both: symbols and footprints.

2) gschem and pcb are historically distinct. There are strong forces in 
the developer community that discourage any closer relationship between 
than the current import-export. 

3) There is consensus, that the current library is in poor shape. But 
there are diverging opinions how a good default library should look like. 
 

> For instance, there are 3 different LED symbols. One in "Basic devices",
> two in "Diodes (generic)". Two of them have the anode on pin 1, the
> third one has it on pin 2.
> When trying to find a footprint for it, there are more than five for
> each of 3mm and 5mm LEDs. For *none* of them does the silkscreen
> indicate the position of the anode or cathode. LED3 and LED5 from
> pcblib/~geda actually present this information in their
> name/description: "(pin 1 is +, 2 is-)". In pcblib/~optical, however,
> the squared pin is named "-" (in red in preview, still not on the
> silkscreen).

The default library of gschem is a known weakness. It was already in 
exactly the same shape in 2005 when I started to work with geda.


> How do you usually handle this ?

I don't use the default lib and rely entirely on my homegrow symbols/
footprints. See my section on gedasymbols.org.


> Maybe you are able to remember what
> footprint will match which symbol, but I don't use gEDA often enough for
> that. 

No. All my symbols contain a default footprint. One of my favourite 
feature requests is the ability to give a list of default footprints. 


> Or do you build your libraries of symbols and footprints that you
> *know* (or hope) are correct ?

yes.


> Perhaps the state of the SMDs footprints is not that bad ?
> 
> I'm now slowly building my own libraries of footprints and heavy-wheight
> symbols, to avoid mismatch between symbols and footprints.

Please consider uploading them in your own section at gedasymbols.org :-)

---<)kaiamrtin(>---
-- 
Kai-Martin Knaak                                  tel: +49-511-762-2895
UniversitÃt Hannover, Inst. fÃr Quantenoptik      fax: +49-511-762-2211	
Welfengarten 1, 30167 Hannover           http://www.iqo.uni-hannover.de
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