Re: gEDA-user: Split ground planes and zero ohm jumpers

[Stephan Boettcher <boettcher@xxxxxxxxxxxxxxxxxx>]

rickman <gnuarm.geda@xxxxxxxxx> writes:

> On 4/7/2011 1:13 PM, Stephan Boettcher wrote:
>> rickman<gnuarm.geda@xxxxxxxxx>  writes:
>>
>>> I have to say I am philosophically opposed to any feature that allows
>>> a design to pass DRC when the layout differs from the schematic.
>> Just to get the terminology right:
>>
>> DRC has no business to care about the schematics at all.  There shall be
>> a tool to check if the layout implements the schematics netlist, but
>> that is a different issue.
>>
>> PCB implements this distiction properly.  DRC checks consider coper
>> structures as layed out when evaluating the rules, without regard to the
>> netlist.
>>
>> The Rat's-nest (O-key) ignores DRC rules when checking connectivity.
>
>  Ok, if you want to be pedantic the net list is not the schematic, but
> if the netlist differs from the schematic, then you have another
> problem.

My point is, what I (we?) call DRC in the PCB program context is the
Menu item Connects -> Design_Rule_Checker. This action does not check if
two nets are connected or not.  It just checks if the connection has the
proper copper width.  It does not care which copper belongs to which
net, or if all pins on a net are really connected.

And, yes, that may be pedantic, but I believe in this context we should
get the teminology right in our discussions.  This is independent of the
issues you are arguing, though.

> DRC is a part of my design process which includes a verification that
> the layout matches the net list.  In fact, my number 1 "design rule"
> to be checked is that  they match.  What button I push to get the tool
> to do my required design rule checking is irrelevant.  It is just a
> tool and does not define my process.
>
> So my point is that adding an attribute to any copper to tell the tool
> to ignore the connectivity violates my idea of design rule checking.
>
> Rick

-- 
Stephan


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