kicad-developers team mailing list archive

[Wayne Stambaugh <stambaughw@xxxxxxxxxxx>]

On 12/15/2010 8:17 PM, Karl Schmidt wrote:
> On 12/15/2010 06:37 PM, Wayne Stambaugh wrote:
>> It will also require some diligence on the
>> user's part but I would rather not limit pin swaps to electrically
>> equivalent pins.
> 
> I understand not wanting to tie someones hands - but I'm not sure how
> that is useful?

Karl,

I gave an example of how it would be useful for parts with high pin
counts to untangle your schematic layout.  We are talking about two
different concepts.  You are talking about the logical or functional
equivalency of pins and I am talking about there locations in the part.
 I think both of these concepts have a place.

> 
> Just to be clear, some of the auto routers use swap information - and
> they need to know that they are swapping the two pins from an and-gate
> rather than a data line an an enable. Seems like what you want to do
> should at least require a 'mother may I'. Wouldn't that just be editing
> the netlist?

We don't have that information now that I'm aware of so we surely cannot
be providing it to any auto routers.  I don't know that I want an auto
router to change nets in my designs without hacking the changes into my
schematic.  I get kind of grumpy when my board do not electrically match
my schematic.

> 
> To be swappable - the pins would need to be within the same gate, be of
> the same type, and thus the same electrically.

This would require a logical equivalent element to list all the pins
that are logically equivalent.  In any event, AFAIK our current net list
format has no way of passing this information to PCBNew or any other
board layout tool.  Not that this should stop us from implementing this
for use in the future.  Maybe I should change the current pin_swap to
pin_relocate and use pin_swap to indicate that pins are interchangeable
a the net list level.  So for a 7400 gate A:

[(pin_swap 1 2)]  #indicates that the inputs can be swapped by the router.

Anyone else have any suggest
> 
> I must be missing something..
> 
> BTW, I remember there was a way where you could even do auto swapping
> that would help untangle the rats nest on the layout.

In PCBNew?

Wayne

> 
> 
> 
> --------------------------------------------------------------------------------
> 
> Karl Schmidt                                  EMail Karl@xxxxxxxxxxxx
> Transtronics, Inc.                              WEB http://xtronics.com
> 3209 West 9th Street                             Ph (785) 841-3089
> Lawrence, KS 66049                              FAX (785) 841-0434
> 
> Did you ever notice that in legal disputes it is only the lawyers that
> win? kps
> 
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>