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Re: gEDA-user: Christmas wishlist





Stephan Boettcher wrote:
kai-martin knaak <kmk@xxxxxxxxxxxxxxx> writes:
Bob Paddock wrote:

This is a DRC issue. The rules should allow any net to connect
to no-net copper. No need to restructure the way pcb handles
connectivity.
If different nets connect to the same no-net copper there is a short
between nets.
Of course, connectivity needs to be recalculated (automatically)
after a net has been connected to a no-net. As a consequence, the
no-net copper will have been converted to what ever net it was connected to.

Maybe it is important to recognise, that DRC and LVS are completely
orthogonal in PCB, and I think that is a good property, that should be
kept.

DRC (DesignRule Check) does not consider the netlist.
This is obviousely wrong, if you layout a copper trace between two net-compatible
pads/pins in one go vs. routing to a wrong pin.
 It checks the
connectivity of all copper, and verifies the rules for connected and
not-connected copper.
The problem is, that all copper patches not connected to a know net are considered to be on different nets - that is a completely arbitrar design choice and in no way
supperior to treating them as on the one "unknown" net.
LVS (Layout vs Schematic) checks that the copper connections between
pins matches the netlist, without checking for DRC rules.
How do you do that, without testing individual line/arc elements for overlap -
which is a DRC matter ?
Distinguishing between net and no-net copper will break this separation.
This should not be done lightly.
As far as I can judge, there is no such separation - there's just datastructures,
that don't support net-attributes for lines etc.


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