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Re: Castellated edge support in v5.99


Local rules will be done with zones: you can give a name to a copper or
keepout zone and use it to define a rule. If you want a zone that is only
used to define a rule and has no other effect, use a keepout that has no
restrictions set.

Regarding castellations, I think we should study an example case and see if
it can be allowed easily with the current set of rules planned, and if not,
add whatever is needed to make it so. I agree it's common enough that it
should be not too hard to make castellations that pass DRC.


On Thu, Jul 23, 2020, 03:24 Eeli Kaikkonen <eeli.kaikkonen@xxxxxxxxx> wrote:

> KiCad doesn't have any specific support for castellations, and doesn't
> need anything special because it's basically PTH pad on the edge. It
> works so-and-so in 5.1: it doesn't complain about pad copper which is
> too close to the edge, and it's even possible to add SMD pads to the
> footprint so that it's possible to route without DRC problems. (See
> https://forum.kicad.info/t/how-to-design-castellated-pins/23945 .)
> However, this doesn't work so well in 5.99. DRC check handles pads
> like other copper and the only way to turn off errors is to ignore
> "Board edge clearance violations" altogether.
> We could of course have some specific support for castellation, like
> marking footprints as castellation and then allowing copper and
> routing there. But I doubt this is what the team wants because it's a
> special case which can be solved otherwise (like local neckdown for
> tight IC's).
> It' not clear to me how the local rules is going to be implemented.
> Will there be some kind of graphical polygon where I can define the
> rules with the DRC Rules editor? That would work for me if it's made
> easy enough.
> I thought about being able to add certain kind of predefined rules
> without a need to write them. For example
> * Add a box around the area
> * Open the context menu on the box
> * It reveals menu item "Add Rules"
> * -> "Castellation"
> Then it would allow the pads on the edge, and also routing and zone
> filling fully without caring about the edge line inside the pad
> boundaries (the rule system must of course support this!).
> On the other hand, castellation is pretty much a de facto standard and
> it wouldn't hurt to support it as a special case. Even allowing THT
> pads on an edge where the hole is on the edge, too, would be enough to
> allow the same workflow than in 5.1.
> Splitting board edge violations into two, pad and other, would also
> work. I never want to violate with traces, but sometimes in a tight
> design I have placed pads very near to the edge and trusted that the
> manufacturer removes copper if they want and there's still enough room
> for the component. This would also allow non-castellated edge plating
> with a footprint (which must otherwise be handled with local rules,
> like castellation).
> Finally, being able to select a bunch of violation markers - for
> example for one footprint - and excluding them permanently could also
> work.
> Eeli Kaikkonen
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