On 22.04.2016 15:11, Chris Pavlina wrote: > You've never seen an EDA package support net ties? Or seen them used to > separate logical power planes? Quite common, really...
Me too. IMHO it can be done without any changes on the eeschema side by adding a special component to the standard library (just like GND/power ports). PCBnew could interpret it as a zero-sized copper pad. Some DRC modifications would be needed to correctly take into account clearances of the nets connected by a tie. Tom > > 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 : kicad-developers@lists.launchpad.net >>> Unsubscribe : https://launchpad.net/~kicad-developers >>> More help : https://help.launchpad.net/ListHelp >>> >> >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~kicad-developers >> Post to : kicad-developers@lists.launchpad.net >> Unsubscribe : https://launchpad.net/~kicad-developers >> More help : https://help.launchpad.net/ListHelp > > _______________________________________________ > Mailing list: https://launchpad.net/~kicad-developers > Post to : kicad-developers@lists.launchpad.net > Unsubscribe : https://launchpad.net/~kicad-developers > More help : https://help.launchpad.net/ListHelp > _______________________________________________ Mailing list: https://launchpad.net/~kicad-developers Post to : kicad-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~kicad-developers More help : https://help.launchpad.net/ListHelp
