RE: gEDA-user: A couple o' questions

["Mark Cianfaglione" <mark_cianfaglione@xxxxxxxxxxx>]

Hello
 I'd like to add a couple of cents worth here....
> 
> Actually, I am very disturbed by this, and have been for some time.
> We encourage newbies to put a NC symbol on no-connect pins so 
> the design passes a DRC check.  However, this symbol causes 
> all the NC pins to be connected together. This is not a good 
> idea, particularly since it's an easy trap for newbies to get 
> snared by. 
> 

I've actually used large scale EDA tools (Unicad - a very good tool 
written by Nortel and now owned by Cadence) that forced you to do this as
well
but the layout person (usually in another department) was trained not to
route the NC net. While autorouting there was a file which contained the 
names of the nets which were not to be routed. This allowed groups of nets
to be routed in order of importance.

> I'd personally prefer that the DRC simply not report unconnected pins
> -- a usually harmless thing -- than encourage a practice 
> which can inadvertently lead to bad boards simply to pass a 
> DRC.  

In actual fact this is the default for yet other large scale EDA tools
(Cadence Concept/Allegro and Mentor Graphics Board Station) The reasoning 
(as it was explained to me by the Cadence Concept architects) for this was
so that you could get a layout done by a less trained layout operator.

So technically either way is good as long as are, as Stuart pointed out,
consistant...

Mark