gEDA-user: TQFP package problem

[Stuart Brorson]

On Thu, 27 Jul 2006, watashi_metan at mailcan.com wrote:

>>> I have problem with gsch2pcb and
>>> /usr/share/gEDA/sym/micro/ATmega128-3.sym.
>>> I added this one to .sch file run gsch2pcb on it and get this result:
>>>
>>> U1: can't find PCB element for footprint TQFP64 (value=unknown)
>>> So device U1 will not be in the layout.
>>>
>>> Other packages like DIP or SO are working but when I try to add
>>> any of *QPF* I got the same problem.
>>>
>>> Is there something I'm missing?
>>>
>>> I'm have geda 20060123 and pcb 20060422 on gentoo x86.
>>
>> sounds like you don't have the right name.  Try "TQFP64_14" instead of
>> "TQFP64".  This would be a good candidate for IPC names and IPC
>> footprints but I haven't had time to do it.  To help get the right
>> footprint name, open up the library browser in PCB or look at
>> http://www.gedasymbols.org/footprints/ and the ~geda library.  The
>> correct footprint name is a link to a preview.

> thanks a lot

>> I'll take the opportunity to warn that descriptions like "64 pin TQFP"
>> are dangerous.  QFP's come in 0.5, 0.65, 0.8, and possibly 0.4 mm pin
>> pitch so you may find two QFP's with the same pin count but different
>> pin pitch.

> Acording to datasheet from atmel.com atmega128 have two variants one is
> some kind of bga
> and the second is TQFP64_14. Then in my opinion it can be safely changed
> from TQFP64 to TQFP64_14 in /usr/share/gEDA/sym/micro/ATmega128-3.sym.
> Because it's quite a bit confusing when you add symbol from geda library
> and it doesn't work.

Here's another reason to eschew heavy symbols in the gEDA distribution -- 
Newbies just assume that they will get the footprint they want from any 
particular symbol.  Better,
IMO, to force everybody to manually assign the footprint after placing the 
symbol.  That way you know what you are getting.  Or at least you have 
only yourself to blame when things go awary.

Stuart