| ID: | 5650 |
| From: | ka...@aspodata.se |
| Date: | Mon, 16 May 2022 16:32:00 +0200 (CEST) |
| Subject: | Re: [pcb-rnd] RFC: multi-sheet netlist |
| in-reply-to: | 5649 from rn...@igor2.repo.hu |
| replies: | 5652 from Nicklas SB Karlsson <nk...@nksb.eu> , 5653 from rn...@igor2.repo.hu |
Igor2: ... > There are basically 3 approaches: > > 1. non-hierarchical, multi-sheet design ... > In this setup all pages of a project are put in a flat list. If you think > in hierarchies, you can imagine a virtual empty top sheet that implicitly > refers to all your sheets in your project. Or in other words, if gschem > had a project file that simply listed all your sheets so all tools could > understand what sheets your project consists of.... Anyway, these are > totally equal sheets without any explicit inter-connection (symbols or > other means), relying on _project global namespace_. ... > 2. hierarchical design with namespaces ... > In this setup you do NOT want to have a global namespace, because you have > referenced the very same amp channel twice, so it will have the same net > names and symbol names. You want a per sheet local namespace so your amp > copies are independent. Then you do the necessary communication/connection > through symbol pins on the top sheet and in/out symbols in the amp sheet. ... > See also: how default gschem 74xxx symbols have GND and Vcc pins connected > from attributes.... Looks like a good idea first, no need to manually > connect gnd and vcc all the time... Until your first design where you have > a 3V, 3.3V and 5V section and you have to be super careful what you power > from where and a careless "this is power, just vcc..." thing brings out > the smoke. Agreed, the NET attribute is a misfeature. > 3. mixed > > I am not sure gschem supports this, but in theory it is possible to > combine the above two, and the cschem data model allows that. The idea > that your hierarchic design normally workds like 2., but then in some rare > cases you may want to have a GND or other connection "global". So there's > extra syntax for letting you do that. ... > Conclusion: > > So far I am not aware there's a 4th use case. I think the gschem > model supports only 1 and 2. The cschem model supports 1, 2 and 3. In the "gschem" model, the difference between 1,2,3 is what prefix attribute you use. In lepton since 1.9.17 (20211219) you can use a empty value, thus lepton support all three models. Gschem does not, but you can patch it to do so. > pcb-rnd at the moment supports 1 only. ... > The hierarchic netlist support in pcb-rnd will mean you can draw your > amplifier channel once, save it as a subcircuit (that contains > subcircuits), and when you are drawing the top level board, the whole > thing is placed. That would be ground breaking, I would really support such a feature. Regards, /Karl Hammar
Reply subtree:
5650 Re: [pcb-rnd] RFC: multi-sheet netlist from ka...@aspodata.se
5652 Re: [pcb-rnd] RFC: multi-sheet netlist from Nicklas SB Karlsson <nk...@nksb.eu>
5653 [pcb-rnd] gEDA "NET" attribute and subc-subc, really tool suite plans (was: Re: RFC: multi-sheet netlist) from rn...@igor2.repo.hu
5654 Re: [pcb-rnd] gEDA "NET" attribute and subc-subc, really tool suite from rn...@igor2.repo.hu