gEDA-user: Gschem/PCB: how to deal with "special" pins & pads?

[Richard Rasker <rasker@xxxxxxxxxx>]

Hello,

I'm a happy GSchem + PCB user for quite a few years now, but I'm still
puzzled about one aspect of defining symbols and footprints, and that is
"special" pins and pads. With "special" I mean the following types of
pins/pads:

- Internally connected pins and pads, e.g. SO8 MOSFETs with 
S on pins 1-3, G on pin 4, and D on pins 5-8. I can of course create a
GSchem symbol with 3 pins for S and 4 pins for D, but is there a more
elegant way in GSchem to deal with this?

- So-called "don't care" pins and pads, e.g. mounting pads for SMD
connectors. I found that I can at least connect these to each other when
I give them all pin number 0 (zero), but I can't connect these to any
net (e.g. Gnd) in the circuit without the DRC check crying foul. Is
there a way to define these pads in such a way that PCB doesn't care to
which net each one is connected?

- Pure holes (e.g. for plastic positioning nubs of SMD connectors):
these often fail DRC check when too close to copper surfaces (e.g.
mouting pads) -- probably because mounting holes are genarally used with
metal screws.

Ideally, one should be able to define the following types of pins/pads:
1. Unique pins (one pin number each, one pinseq number each)
2. Interconnected pins (range of pin numbers, one pinseq number)
3. True don't care pins (each can be connected to any net, or no net at
all)
4. Interconnected don't care pins (all pins can be connected to one
particular net, or no net at all, e.g. with connector mounting holes).

Am I correct in surmising that gEDA currently only accomodates type 1?
If not, how can I define these special pins/pads, both in Gschem's
symbols and PCB's footprints?

Yes, ïI dug up quite a lot of previous discussions on this subject, but
no clear solutions or references to manuals.

Thanks in advance,

Best regards,

Richard Rasker



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