X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f X-Recipient: geda-user AT delorie DOT com X-TCPREMOTEIP: 207.224.51.38 X-Authenticated-UID: jpd AT noqsi DOT com Content-Type: multipart/signed; boundary="Apple-Mail=_0CF17028-1708-4D36-A3CE-7BD6EA11A680"; protocol="application/pgp-signature"; micalg=pgp-sha512 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Subject: Re: [geda-user] A lesson from gnet-makefile X-Pgp-Agent: GPGMail 2.5.2 From: John Doty In-Reply-To: <20151012220649.da6dfea4f040e5fb8300ae9c@gmail.com> Date: Mon, 12 Oct 2015 15:57:50 -0600 Message-Id: References: <1042003D-82E2-40F0-AB60-8186580C46AD AT noqsi DOT com> <20151012220649 DOT da6dfea4f040e5fb8300ae9c AT gmail DOT com> To: geda-user AT delorie DOT com X-Mailer: Apple Mail (2.1878.6) Reply-To: geda-user AT delorie DOT com Errors-To: nobody AT delorie DOT com X-Mailing-List: geda-user AT delorie DOT com X-Unsubscribes-To: listserv AT delorie DOT com Precedence: bulk --Apple-Mail=_0CF17028-1708-4D36-A3CE-7BD6EA11A680 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 On Oct 12, 2015, at 2:06 PM, Nicklas Karlsson = (nicklas DOT karlsson17 AT gmail DOT com) [via geda-user AT delorie DOT com] = wrote: >> Folks, >>=20 >> I had thought that the lack of a way to access attributes other than = netname=3D on a net via gnetlist was a serious barrier to the back end = writer. However, for gnet-makefile.scm I find myself using the = attributes of the attached symbols as a rich source of information about = the net. Is this perhaps the best approach anyway? >>=20 >> Nets in a schematic represent collapsed topology, not geometry or = even the complete topology. The layout system is responsible for these = things. A schematic doesn=92t capture the relationships between the net = segments. Some paths on a net may carry large currents, but others may = not. Pairs of nets may represent balanced transmission lines. >>=20 >> But, suppose instead that we had a pin attribute that said =93this = pin may draw three amps=94. The netlister could then deduce which paths = on a net need extra conductor. >>=20 >> Suppose a resistor had an attribute that meant =93100 ohm shunt = terminator=94. Imagine a component with a pair of pins identified by an = attribute as a differential input. Put them on the same pair of nets, = and the netlister could deduce that the pair is a balanced transmission = line and the the resistor needs to be close to the input. >>=20 >> Of course, we=92d need a layout program that could accept this info. >>=20 >> John Doty Noqsi Aerospace, Ltd. >> http://www.noqsi.com/ >> jpd AT noqsi DOT com >=20 > As I understand it you want to assign attributes to pins instead of = nets. >=20 > A net is only allowed to have one driver and will get the voltage of = the driving pin and from this voltage a suitable clearance may be = selected. For current it will be the other ends. Seems rather rigid. Some circuits are like that, others not so much. But = it=92s a good first approximation, better than anything we have. > It might work but I still think net names are useful sometimes, maybe = it would be useful to use the driving pin to assign the net name, if = this is simple to implement I guess it would be worth a try. You can do that with the net=3D attribute on a symbol, if you like. I = don=92t see anything new or special about the net name. The other things = you can learn about it by looking at what it=92s attached to interest = me. >=20 John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ jpd AT noqsi DOT com --Apple-Mail=_0CF17028-1708-4D36-A3CE-7BD6EA11A680 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJWHCzeAAoJEF1Aj/0UKykRGLcQAKXCWVIX46iZ9YnVKEz4ZuBo AEETrOee49no8kJzeG+exasGIxBJBQ6FkSvyGvOetXcIRWzjyfd9DcKlYfqsvc6s M1prPWfB5DlXNyDNqikCm3asUPuznKGYYifOJRmVv5UeyYUgD+DQibRAhdjYGAVC J9VzTRVvkP5kq02fbseOTQE7a/g/slKCbry+BPtpDEAJbMcva6v4RtvtSJ2TC5bT E/w2xzn1KHeDFiizs+BnZKHMu0bc4n6Hd9AEN+uf9uFLzKNRcNCeP15gm/Rhue7a HTM0Mul7NV6GRCLbx7wZyYvDNAg27ZuyNEFlhv69afEdR1ePijDraRggxzzDCbHv qDlksSRIXWgpO696ItkBiGLuxH0K6ve6aIQtAyy7jiirsWK1Oa1z+9ux+BusQntP F5qAcGSarHN4+3fNWl6GlQOqpcipRR/NeT5PwTsoSqM3C4D3fpg/7lLbglYudXkJ L8bdhrtRJ163rFmHIVF+FdYQTbDgEPnwoMfhyBt3lEvxTOkTSbgKywFYYrwV0hQS z0ShUZgFWbjxBcJCzKK5ZlvgUhiTugRlqGnKANZHE0DGH4q+SWekIAwUSOn8iQJ/ hwSBnkkjXXG4MUvTzCgHwkWSbAHNfk1bQEOdX0zKMf7lRJKR8Yh/ONhE2nYsjKbK WHtHAoTe7QYED/LuoSye =lhjB -----END PGP SIGNATURE----- --Apple-Mail=_0CF17028-1708-4D36-A3CE-7BD6EA11A680--