Re: gEDA-user: Split ground planes and zero ohm jumpers

[John Griessen <john@xxxxxxxxxxxxxx>]

On 04/07/2011 04:52 AM, Stephan Boettcher wrote:
> PCB layer groups may be used here.  Put the short on an extra layer, in
> an extra group.  At checkout time, you can assign the extra layer to the
> group representing the copper layer that needs shorting.  This is
> probably a single char in the PCB file header, and can be done with a
> simple sed script.

I like that idea -- at least until someone figures how to have a starpoint
symbol and footprint that keeps DRC checking of separate ground planes while
still having a short there for fabbing purposes.

I'm thinking of two scripts external to pcb, for use with make.  While editing
a pcb board, I would run DRC and effectively have a non conductive piece
of trace between separately named ground planes.  When I run make faboutput,
one script is run to change the non conductive piece
of trace to copper on a layer, then output RS274-X, the run the other script
to change the piece of copper on a layer to a non conductive piece
of trace.

We don't have the concept of non-conductive built into pcb now though,
so some kind of "ignore for DRC purposes" might do.

There's still a problem with that method though... It won't check for
proper clearances of the starpoint blob of copper to other copper if it
is handled by an "ignore for DRC purposes" attribute.

The real way to have starpoints handled at schematic level is to allow for two different
named nets to touch at one overlap.  Nets would have to be defined by attributes
plus layer connectivity rather than layer connectivity alone.

John
--
Ecosensory   Austin TX


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