[Xcircuit-dev] rubberband lines

[R. Timothy Edwards]

Dear Gary,

> How can you tell if the pins are connected to wires?

Try the option "Options->Show Pin Positions".  Then, if you select
a wire and highlight the connectivity (Alt-w), the pin position marker
"x" will be highlighted if it's connected to the net.

> I would venture a guess that an automatic schematic generation wouldn't 
> be very readable, even if the wire and components were placed cleanly. 
> Well, at least in analog design, where circuits are really combinations 
> of simple building blocks. Current mirrors, source-coupled pairs, 
> cascode, etc. They only look recognizable when drawn a certain way.

The idea was to use a corner-stitched tile database to chop up areas
of the schematic into routable regions, and then arrange wires to
minimize both crossovers and crowding.  At least that was the idea
for the part of the ASG system that mimics rubber banding.  Full
ASG (converting a SPICE netlist into a schematic) does indeed run
into the problems you mention, which is often helped by being able
to detect specific structures in the input like mirrors and cascodes,
and handle them appropriately.  I agree that dropping components onto
a page and then routing them is only marginally better than staring
at the SPICE netlist itself, unless you're really careful about the
placement and routing.

					---Tim

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| Dr. R. Timothy Edwards (Tim)   | email: tim.edwards at multigig.com     |
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