Re: [PROTEL EDA USERS]: Problem with Power Pins

[Abd ul-Rahman Lomax <marjan@vom.com>]

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At 10:00 PM 9/1/00 +1000, Ian Wilson wrote:

>Rant On
>I have a deep hate of hidden pins.  Some on this list tell me they have 
>uses.  I am only a youngster in this game (15 years) but I have never seen 
>a place where hidden pins and worse, automatic net connection of hidden 
>pins does anything but make life harder for everyone but the person laying 
>out the original schematic.
>
>My suggestion is to edit every sch symbol that you use and remove the 
>hidden pins - make visible power pins (and make them of type POWER so the 
>ERC is working for you).
>
>Others though do offer support for Protel continuing a confusing and 
>fraught-with-problems historical aspect of early computer based PCB CAD 
>systems.
>Rant Off

I commend Mr. Wilson for knowing when he is ranting....

I agree that hidden pins can be a problem, but once one knows how they 
behave, they are not much of a problem. Designers who don't like hidden 
pins are certainly free to avoid or modify components that use them, or to 
globally change all components to show all pins.

But Protel *must* support hidden pins because it must be able to import 
schematics which use them.

As to their utility, if one has a digital design with many discrete gates, 
hidden pins are a godsend....

Ever reassign gates or op-amp sections on a schematic with no hidden pins 
and discover that your power connections are now disconnected? This doesn't 
happen when hidden pins are used for power.

Yes, one can have a special page for power sections of ICs, and this is 
also a good place to put bypass caps as well, thus associating the caps 
clearly with their ICs. I do, in fact, agree that this is a superior 
solution, at least in some respects, but Protel should not impose "superior 
solutions" on designers; it is enough to make them possible.

marjan@vom.com
Abdulrahman Lomax
P.O. Box 690
El Verano, CA 95433



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