kicad-developers team mailing list archive

[Simon Richter <Simon.Richter@xxxxxxxxxx>]

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
 - Current sense resistors between a supply rail and a load
 - Decoupling capacitors.

I've added UI[1] and save support in eeschema already, still needs
mapping to the netlist and pcbnew support.

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.

   Simon

[1] http://psi5.com/~geier/net-tie.ogv
[2] http://cds.linear.com/docs/en/design-note/dn434f.pdf

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