gEDA-user: DRC problem at close pads

Dan McMahill dan at mcmahill.net
Mon Feb 26 17:47:55 EST 2007


David Kuehling wrote:
>>>>>>"DJ" == DJ Delorie <dj at delorie.com> writes:
> 
> 
>>>http://user.cs.tu-berlin.de/~dvdkhlng/clearance-problem.png
> 
> 
>>Could you post (or send me privately) the .pcb file?
> 
> 
> Here is a simplified file that only contains the problematic footprint.
> Quite possibly this is just a problem with the footprint?  After all
> this was hand-coded in M4...

I'd be more likely to suspect the footprint if "after all it was hand 
drawn instead of generated programattically"...

Ok, here's the deal.  It is a bug in pcb.  Square (or rectangular) pads 
are checked by growing one of them in X and Y on all 4 sides by the 
minimum space.  This of course means that the corners grew by sqrt(2) 
more and thats why you got a failures.  I'll try to cook up a patch tonight.

I took a quick look at that footprint and it is similar but not quite 
the same as the TQFN_40_6_EP in the ~geda library.

-Dan


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