You've never seen an EDA package support net ties? Or seen them used to separate logical power planes? Quite common, really...
I'd _love_ to see proper net tie support in KiCad. :) On Fri, Apr 22, 2016 at 09:04:10AM -0400, Wayne Stambaugh wrote: > On 4/20/2016 4:00 PM, Simon Richter wrote: > > Hi, > > > > as wxWidgets is getting on my nerves with editing widgets in the pin > > table not rendering properly, I've started on support for net ties. > > > > In the current iteration, they would be placed the same way as junctions. > > > > Rules: > > > > - Any wire or pin connected to a net tie is in a separate net (unless > > connected elsewhere). > > - The net tie maps to a pseudo-pad that all three nets need to be > > connected to. > > - Connecting the nets there does not give a DRC error -- anywhere else > > will. > > - The pseudo-pad can be placed on a regular pad if it is on one of the > > nets connected to the net tie. > > > > Use cases: > > > > - Analog and digital supply planes connected with a trace, but > > otherwise separate > > I'm going to put my EE hat on and say that if you connect two power > planes with a trace then they are the same plane no matter what you > called them in your schematic. A more typical solution in this case > would be to physically separate them by some type of component or > components. Usually inductors or 0 ohm resistors (aka jumpers) are used > in this situation depending on what you are trying to accomplish. > > > - Current sense resistors between a supply rail and a load > > - Decoupling capacitors. > > I can see the decoupling capacitor use case where you want to tie a cap > to a specific component power pin. > > > > > I've added UI[1] and save support in eeschema already, still needs > > mapping to the netlist and pcbnew support. > > Are you aware that changes to the current schematic file format are > forbidden until we (I) finish implementing the new file format? This > was discussed fairly recently so everyone should be aware of this. In > any event, you should have gotten input from the development team before > heading down this path. This is good advice for any developer. Even I > solicit input on new features or large changes because other devs always > seem to think of things I didn't. > > I don't have a strong opinion one way or the other about this feature. > On the surface it does seem useful but I've never seen any EDA product > support this so board designers may not understand why they would want > to use it. Any one else have any thoughts on this? You may also want > to check with the users to see if it's something that they would even use. > > > > > There doesn't appear to be a real standard on how to represent net ties > > in the schematic, though. A design note[2] from Linear Technologies uses > > 45 degree angles on wires to make it look really intentional that the > > wires should meet in the same spot, but that would be a major hassle > > both to implement and use. > > > > For now I've gone with a larger dot, but that is very unintuitive. > > Printing net names next to wires is difficult, because these are still > > wires only. Numbers next to the wires might be doable, but confusing, so > > if anyone has a good idea how to represent them, please speak up. > > How about a different color dot or a different shape. A different shape > may be better for users who are color blind. > > > > > Simon > > > > [1] http://psi5.com/~geier/net-tie.ogv > > [2] http://cds.linear.com/docs/en/design-note/dn434f.pdf > > > > > > > > _______________________________________________ > > Mailing list: https://launchpad.net/~kicad-developers > > Post to : [email protected] > > Unsubscribe : https://launchpad.net/~kicad-developers > > More help : https://help.launchpad.net/ListHelp > > > > > _______________________________________________ > Mailing list: https://launchpad.net/~kicad-developers > Post to : [email protected] > Unsubscribe : https://launchpad.net/~kicad-developers > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~kicad-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~kicad-developers More help : https://help.launchpad.net/ListHelp
