Mail Archives: geda-user/2017/01/28/11:49:12
Nicklas Karlsson (nicklas DOT karlsson17 AT gmail DOT com) [via
geda-user AT delorie DOT com] schreef op za 28-01-2017 om 15:06 [+0100]:
Hello Nicklas,
> On Sat, 28 Jan 2017 13:41:00 +0100
> "Richard Rasker (rasker AT linetec DOT nl) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com> wrote:
>
> > Lately, I started on projects involving Bluetooth and UHF RF, and for
> > simplicity and cost, I'd like to use PCB antennas.
[snip]
> This is what I found about the footprint format
> http://www.ssalewski.de/PcbFootprintRef.txt and there is limitations.
Yes, I already found this definition, and from what I see, a PCB
footprint element can only contain pins and simple(*) pads as copper
items. Lines and arcs are strictly silk screen items.
*: rectangular or rounded lines, no polygons etc.
[snip]
> The source is out there and I guess this would rather simple to check
> a flag if object should be not be considered as conductive if we could
> just agree about a suitable flag or attribute?
Indeed, a sort of "no-net" flag could provide a solution; this flag
would signal that the copper item should not be treated as a connection
in the netlist.
In addition, it would be desirable to include lines, arcs and polygons
as copper items within an element. But as it is, PCB doesn't have this
functionality.
I was hoping there was a work-around for this, but I guess I'll simply
leave any PCB antenna connections until last, to avoid getting error
messages all the time. And it's not that big a deal -- usually a design
contains only one antenna.
> > *: A related question: when defining connector footprints, I usually
> > define all mechanical metal parts as pin/pad 0.
>
> What do you mean by mechanical part?
I mean any metal parts that aren't functional electrical connections,
such as pins and/or fasteners (e.g. screw holes) for mechanically
mounting a connector to the PCB.
Often, it is desirable or even required to connect these metal parts to
a ground plane, which means they must have a netlist entry and thus a
defined pin number to avoid error messages. So I usually give these
pins/pads the number 0.
But come to think about it, this is not a case where the aforementioned
"no-net" flag would apply -- because often, several metal mounting pins
are interconnected in the connector itself. This means that the actual
connection must be recognized as such, contrary to PCB antennas and the
likes. So this is a different thing.
Best regards,
Richard Rasker
Linetec
--
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e-mail: rasker AT linetec DOT nl
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