Re: gEDA-user: Metric PCB footprints using 1mil grid

[Steve Meier <smeier@xxxxxxxxxxxxxxxxxxx>]

The current resolution of pcb being 0.01 mills which translates to 254
nano meters (~1/4 of a thousandth of a mm)  should meet the requirements
for printed circuit boards for some time (metric or english). And yes
being able to create/translate foot prints in metric units to pcb units
would be usefull. This doesn't have to be a built in pcb function it
could be a foot print generator capability. An argument for having it is
to reduce the errors caused by humans.

Steve Meier


Ben Jackson wrote:
> As I mentioned in an earlier mail, the QFP208_28 footprint I used for
> my board I later found to have 1mil spacing depsite being in the .01mil
> format.  Since it's a metric footprint (0.65mm pitch) the pins vary in
> both width and spacing along each row.  This isn't fatal, certainly, but
> it's not ideal.
>
> I was considering how to detect this problem automatically.  I would be
> fairly easy to identify parts with 1mil accuracy which also have 'several'
> pins in a row with varying pitch and/or width.  It could be done in a
> script, or within PCB.
>
> Would anyone be interested in seeing this detected automatically somehow?
> I was thinking about flagging it in the element picker, but that's not
> typically how elements get into a PCB.  It could also be part of the
> DRC, or it could be a separate report.
>
>   



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