At 06:07 PM 3/14/01 -0600, David W. Gulley wrote:
>Abd ul-Rahman Lomax wrote:
>
> > The vast majority of integrated circuits in designs which cross
> > my desk are single-supply, and the majority of designs have only
> > two power nets: ground and one other.
>
>And as has been demonstrated so many times, one person's experience with
>designs is vastly different from an other's!
>
>  A design I am currently working on has five digital power supplies
>(5.0, 3.3, 2.5 1.8 and 1.2) as well as two analog supplies.

Of course our experience differs. However, I think that if we could collect 
statistics on the designs actually being made with Protel all over the 
world, the majority would be single supply (or dual-supply analog, which 
amounts to much the same thing, only it is V+, V-  and GND). Yes, I also do 
plenty of designs which are multiple-supply, but multiple "VCC" designs are 
more rare.

"More rare" can still be "common", so Mr. Gulley's experience does not 
surprise me at all. And certainly Protel must be able to handle with ease 
multiple-supply designs. The present hidden-pin system clearly is not 
sufficient.

Tango Schematic allowed sheetwise renaming of nets; a particular structure 
was exempt from the net renaming warning (A power port plus a short piece 
of track with a net label was always considered to be a deliberate 
renaming). Thus one could assign VCC on one page to, say, +5V, and on 
another to +3.3V. This was more flexible than what is created by 
inflexible, global-always-when-hidden power pins.

>As to the rest of Abd's message, I agree wholeheartedly:
>[...]
>  Except for the following:
> > A warning that there are hidden power pins on a design would
> > not be a bad idea.
>  With this sentence, I totally disagree with Abd, I think,
>   "A warning that there are hidden power pins on a design
>    *should* be REQUIRED!"

Sorry, I must have been asleep. Thanks for correcting me, David. :-)

[EMAIL PROTECTED]
Abdulrahman Lomax
P.O. Box 690
El Verano, CA 95433

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