kicad-developers team mailing list archive

[James Jackson <james.a.f.jackson.2@xxxxxxxxx>]

Hi Jeff,

The background is that I'm looking at a ruleset which has different rules
depending on whether two neighbouring vias are in the same, or different,
nets. Running the risk of 'feature creep', of course, I think the
constraints can indeed be met by what is there, but I suppose my question
(and apologies for think out loud - the nature of the beast!) can be
considered as 'Can a rule be matched based on whether the two objects are
in the same, or different, nets?' Of course, this could be done by matching
all permutations and combinations of nets, but that would become a
combinatorial nightmare!

Yours,
James.


On Thu, May 21, 2020 at 11:29 AM Jeff Young <jeff@xxxxxxxxx> wrote:

> Hi James,
>
> It sounds like you’re looking for hole-to-hole min.  That’s in the
> existing constraints system in 5.99; you don’t need rules for that.
>
> Or does your hole-to-hole min depend on the specific via, specific
> netclass, or something else?  (The current hole-to-hole min is board-wide.)
>
> Cheers,
> Jeff
>
>
> On 21 May 2020, at 10:54, James Jackson <james.a.f.jackson.2@xxxxxxxxx>
> wrote:
>
> Hi Jeff,
>
> Many thanks for this - looks very powerful, and when it gets hooked in to
> the PNS router will be killer. An issue I'm currently grappling with a
> variety of rules considering placements around vias. Some rules require a
> distance measured from the outside of the annular ring to a track (or
> another annular ring outer edge), and some from the outside of a hole (i.e.
> the inside of the annular ring) to the nearest other outside edge of a
> hole. I suspect the former is achieved with what is currently there, but is
> the latter possible? It's essentially a question of where via-to-via
> measurements are made.
>
> Thanks,
> James.
>
>
>
> On Sat, May 16, 2020 at 4:44 PM Jeff Young <jeff@xxxxxxxxx> wrote:
>
>> I’ve just merged a possible implementation of the DRC rules.  I’d like to
>> get some feedback on it, and also some testing.  (Because the rules support
>> such a wide range of possibilities it’s going to need a good deal of
>> testing.)
>>
>> For now, it picks up DRC rules from a file named “drc-rules” in the
>> project directory.
>>
>> There’s no GUI editor at present: use a text editor.
>>
>> Grammar is s-expr.  It generally follows the ideas set down here:
>>
>>
>> https://docs.google.com/document/d/1qvCH9aHwCzp5qtKTna4jJXuloNU0b96gAxAHSKPuXpU
>>
>> with one major exception: I found the select-a-single-rule didn’t pan
>> out.  You have to duplicate too much stuff in each rule for that.
>>
>> Also, because the DRC engine (and zone filler) don’t currently support
>> min/opt/max the prototype implements min with Seth’s “relaxed” option.
>>
>> Top level is a list; first expression must be (version x) followed by any
>> number of (selector…) and (rule…) expressions.
>>
>> /*
>>  * Match tokens:
>>  *     match_netclass
>>  *     match_type
>>  *     match_layer
>>  *     match_all
>>  *     match_area  (not yet implemented with the exception of “$board”, which matches everything)
>>  *
>>  *     (selector (match_area "$board") (rule "OSHParkClass3") (priority 100))
>>  *
>>  *     (selector (match_netclass "HV") (rule "HV_internal"))
>>  *     (selector (match_netclass "HV") (match_layer "F_Cu") (rule "HV_external"))
>>  *     (selector (match_netclass "HV") (match_layer "B_Cu") (rule "HV_external"))
>>  *
>>  *     (selector (match_netclass "HV") (match_netclass "HV") (rule "HV2HV"))
>>  *     (selector (match_netclass "HV") (match_netclass "HV") (match_layer "F_Cu") (rule "HV2HV_external"))
>>  *     (selector (match_netclass "HV") (match_netclass "HV") (match_layer "B_Cu") (rule "HV2HV_external"))
>>  *
>>  *   TODO: pads for connector pins or wire pads have even larger required creepage clearances.  How to encode?
>>  *   User attributes on parent footprint?
>>  *
>>  *     (selector (match_netclass "HV") (match_type "pad") (match_netclass "HV") (match_type "pad") (rule "pad2PadHV"))
>>  *
>>  *     (selector (match_netclass "signal") (match_area "BGA") (rule "neckdown"))
>>  *
>>  * Type tokens:
>>  *     track
>>  *     via
>>  *     micro_via
>>  *     blind_via
>>  *     pad
>>  *     zone
>>  *     text
>>  *     graphic
>>  *     board_edge
>>  *     hole
>>  *     npth
>>  *     pth
>>  *
>>  * Rule tokens:
>>  *     allow  (not yet implemented)
>>  *     clearance
>>  *     annulus_width
>>  *     track_width
>>  *     hole
>>  *
>>  * Rule modifiers:
>>  *     relaxed
>>  *
>>  *     (rule "HV" (clearance 200) (priority 200))
>>  *     (rule "HV_external" (clearance 400) (priority 200))
>>  *     (rule "HV2HV" (clearance 200) (priority 200))
>>  *     (rule "HV2HV_external" (clearance 500) (priority 200))
>>  *     (rule "pad2padHV" (clearance 500) (priority 200))
>>  *
>>  *     (rule "signal" (clearance 20))                       // implied priority of 1
>>  *     (rule "neckdown" (clearance relaxed 15) (priority 2))
>>  *
>>  *     (rule "allowMicrovias" (allow microvia))
>>  */
>>
>>
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>
>