Mr. Lomax
I would hesitate to let the pcb routing dictate the FPGA configuration. It
has been my experience in the past that this can result in disastrous
synthesis. I would suggest that unless you have full control over the FPGA
simulation, synthesis and layout, that it is best to let the FPGA
programming (Xilinx Foundation or fascimile) dictate what pins get connected
to what signal.
Lloyd Good

-----Original Message-----
From: Abd ul-Rahman Lomax [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, November 21, 2001 12:51 PM
To: Protel EDA Forum
Subject: Re: [PEDA] Pin & gate swapping

At 07:48 AM 11/21/01 -0500, Sean James wrote:
>Does anybody know how to get Protel to do gate & pin swapping?

Protel does not support this automatically. But it is not difficult to go 
back and forth between schematic and pcb to accomplish something similar.

And with a complex assignment problem, where we want to improve routing, 
say, for a many-pin FPGA, I created a single-pin part, popped one of it 
onto each interchangeable pin on the schematic, created a footprint for 
this part which was equal in size to one pad of the FPGA, and placed these 
parts on the corresponding swappable pads of the FPGA. Then, while routing 
manually, I could just move them around until I got a good arrangement; 
I'll leave the rest of the process as an exercise for the student... :-)

But it was not at all difficult to transfer this data back to the schematic.

Two hints:

I made a mech layer copy of the FPGA footprint and replaced the actual FPGA 
with that copy while I was working. This allowed me to pick up the pieces 
with ease -- without going through a selection dialog -- but they still 
would snap into place.

It may be easier to make a special symbol for the swapped FPGA than to use 
the original symbol, which would require rerouting the schematic. However, 
if the swappable nets are assigned to the FGPA with net labels instead of 
wires, rerouting is easy.

Abdulrahman Lomax
Easthampton, Massachusetts USA

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