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Re: gEDA-user: A couple o' questions



It becomes a real can of worms - but if you have a
design specific library, even an _instance_ specific library,
you can get apply attributes that function.

Thats very unfriendly to a beginner however.
And only necessary for analog design.  Or fpga pins.
(or a very long list when I consider for a moment..)

john




John Doty wrote:

On Apr 7, 2006, at 5:43 PM, John Sheahan wrote:

Mark Rages wrote:

The pintype *is* obvious for the "fistful of TTL chips" approach to
digital design, which was commonplace when EDA systems were first
getting developed.  Maybe the pintype DRC is a bit of an anachronism.

maybe DRC applies much better to some types of designs than others.

Yes!


Which would imply to me that DRC should be used judiciously.

Yes! That's the problem with gnetlist's drc2 hard sell.

Perhaps the components themselves should know whether that are good at being DRC'd. Or a DRC rule decks be chosen for purpose?

I think that having pintype default to "pas" would be constructive. That should essentially turn off the pintype DRC for a component whose author couldn't figure it out.


I never figured out the DRC attributes for a bipolar tansistor at board level for exmaple. john

Yep. The roles of the pins aren't properties of the device: they're determined by how the device is used. The emitter might be 'in' (common base), 'out' (common collector), or 'pwr' (common emitter). So, use the escape hatch and call it 'pas'. Won't get checked, but won't cause an error. Yeah, I know, that's not obvious unless you understand the details of how DRC works (or doesn't). That's why 'pas' should be the default.


John Doty              Noqsi Aerospace, Ltd.
jpd@xxxxxxxxxxxxx