[Xcircuit-dev] xcircuit Q&A

[R. T. E. <ti...@st...>]

Dear Bryce,

> 1. I can't find any way to specify power and ground connections in a
> multigate chip.  Maybe one of the instances should have power and ground
> ports, and the others should not?

Put numbered pins for Vdd and GND on the library symbol (such as on top and
bottom).  On any one of the parts in the schematic, attach Vdd and GND
(or attach labels with the global names Vdd and GND) to any one of the
devices.  You will, however, need to post-process the result to get
rid of the redundant entries for those pins, as xcircuit only recognizes
the problem well enough to report "duplicate entries U1 and U1" or something
to that effect.  I will work on this problem.

> 2. The pcb netlist output looks like U1-3-10, meaning part number U1, gate
> number 3, pin 10.  This cannot be parsed in the pcb software, unless I
> change it to just U1-10.  I know how to do this with a perl script to fix
> up the netlist, but is there a better way?

The "info label" for the device has "pcb:U?-1" (or -2, -3, etc.).  Edit
it as follows:  Select the last number in the string (with a middle-mouse-
button select box) and then select menu option "Text->Unparameterize".
Then edit the string and delete the "-1" off the end.  You will no longer
get the sub-component number in the PCB output.

> I'm using xcircuit 2.5.2.  Later versions are crashing on startup with an
> XQueryColors error.  I filed that one too. :)

Yuck.  I may need to see the actual error result, but try this:  xcircuit.c,
routine "findnearcolor" (around line 1807), add as the first executable code
after the type declarations:

   if (ncolors > 256) {
      XQueryColor(dpy, cmap, cvexact);
      return cvexact->pixel;
   }

The rest of the stuff in that routine was supposed to be dealing with
indexed color;  it is not relevant to 24- or 32- bit TrueColor visuals,
and I suspect that's the problem.  But it could be something else.

						Regards,
						Tim