Re: gEDA-user: PCB help . . . .

[Dan McMahill <dan@mcmahill.net>]

On Mon, Sep 22, 2003 at 12:14:27PM -0400, Stuart Brorson wrote:
> Hi --
> 
> Well, I have decided to take the plunge and try doing a layout using
> PCB.  However, I am already flailing.   :-(
> 
> I read Dan McMahill's HOWTO as well as the various PCB docs, and I
> think I am following the instructions more or less.  However, running
> gschem2pcb gives me errors like: 
> 
> Loading schematic [OpticalInstAmp_1.sch]
> ERROR! no footprint attribute in A4
Is this a schematic sheet?  Thats probably ok.

> Error: the footprint C0805 for the device Cbp_amp1 does not exist
> Error: the footprint R0805 for the device Rbp2_amp1 does not exist
> Error: the footprint R0805 for the device Rbp1_amp1 does not exist
> Error: the footprint R0805 for the device RLamp1 does not exist
> Error: the footprint R0805 for the device Ramp1in_p does not exist
>
> Apparently, I am not using the correct name for the desired
> footprints.

exactly.  Those were locally defined.

> My questions:
> 
> *  Where are the footprint names documented?  I have looked at the
> .list and .inc and .m4 files in (what I think are) the various
> footprint directories, but none of the names match those given in
> Dan's HOWTO.  Also, there are zillions of names for each type of part,
> so it is hard to figure out which to use.

they're not well documented.

> *  It looks like there are two types of footprints:  those generated
> using an old method (m4?) and those generated using a new method
> (???).  Is this true?  Where is this documented (if anywhere)?  

this is true.  I've been working on improving the PCB manual and 
plan on checking something in over the next few days.

> *  I am used to systems where the different footprints are just
> individual files holding some graphical information.  Here, it looks
> like the footprints are generated by a collection of m4 scripts, and
> one script might generate many different footprints, depending upon
> its calling arguments.  Is this true?  How does PCB know where to look
> when generating the footprints on the screen?

'newlib' components are 1 footprint per file.  PCB traverses any
directories specified by the Pcb.libraryTree Xresource to find these.
Note gschem2pcb does not understand this but gsch2pcb does.

'oldlib' (m4) components are listed in the pcblib.contents file.  
This file is used to populate the menu in PCB.  Then m4 is called
to expand the macro and produce the footprint.

In general, I try to use the footprints and and naming convention
in the gEDA symbol creation guide and the corresponding geda library
thats included with PCB.  In terms of using 'newlib' or 'oldlib' for
project specific components, I'd make that call based on pin count
(I'd rather program a 320 pin package than draw it) and family reusability
(probably no point in programming a fiber receiver).

>
> I understand that there is an effort underway to translate a PCB
> document out of Portugese into English.  I would be willing to help
> write or edit this doc if I could see an early copy which would help
> me get "over the hump" with PCB.  Just point me to the location where
> the drafts live.

I'll post a mail here as soon as I check in the new docs.  I'll welcome
and additions and corrections.


-Dan

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