At 02:16 PM 11/20/01 +1100, Ian Wilson wrote:
>At 09:46 PM 19/11/01 -0500, you wrote:
>>(This is Design/NetlistManager/Menu/....
>>I forget the exact name, but it is *not* the command that generates a net 
>>list from connected copper. It is the other one, that just dumps what is 
>>loaded into all the pads.)
>Design/NetlistManager/Menu/Create Netlist from Connected Copper

No, not that one. The other one. It is called "export netlist from PCB"

>But this will include the names of the nets.  My detailed instructions 
>were largely based on the requirement that the net names needed to be 
>obfuscated as, is common with a clear schematic, the net names themselves 
>may carry significant IP.  To mask all the possible IP from the PCB it is 
>necessary to remove the net names and substitute generic 
>netlister/synchroniser allocated names.

Normally, there is not significant IP in the netlist, even when fairly 
descriptive names have been used. It would be very rare that one could 
extrapolate back from the net list to an understanding of what the board 
does, unless someone has used *very* descriptive net names, which I have 
never seen. Knowing that an address bus or a reset line is such would not 
be sufficient.

However, it is possible to edit the net names by a similar procedure to 
that which can be used when doing netlist translation. A word processor is 
used to convert the net list net section to a tab-delimited database, one 
net per record, one node per field beyond the netname field. This is then 
imported into a spreadsheet, the netname field edited to a numerical 
sequence which any spreadsheet should be able to accomplish, written back 
to a tab-delimited database, and then edited back into Protel format. It 
took me longer to describe it than it would have taken to do it; but then 
again, I've been doing it for more than ten years -- the Tango format is 
identical to the original Protel format. I have some translation utilities 
written in Quickbasic, but I never bothered to make the full translation, 
it was easy enough in a word processor.

(Protel should have used a tab-delimited format from the beginning instead 
of the one-field per line format that was chosen. It would have not only 
been shorter but could have been much more easily read and manipulated. I 
don't know how many times I have seen a client print out a net list that 
was not translated as I described. Let's see, how many reams do I need to 
load into the printer. It's not too late, the translation is trivial!)

>The netlist is necessary in some circumstances as the 
>bug/problem/issue/feature being demonstrated may require a netlist.  In 
>the case of a completed board the netlist can be generated from the copper 
>as per the above command sequence.  This is not the case in an incomplete 
>board - to be more specific - in a board that is not fully routed.

Actually, you can do whatever works, i.e., if the bug persists with all net 
information removed, so much the better. Basically, before sending off the 
stripped file, one needs to verify that it still does whatever nasty thing 
is being investigated.

Abdulrahman Lomax
Easthampton, Massachusetts USA

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