Re: gEDA-user: Embedded Power Pins

[Gene Heskett <gene.heskett@xxxxxxxxxxx>]

On Saturday 04 March 2006 15:29, Stuart Brorson wrote:
>> Em Sex 03 Mar 2006 21:32, John Luciani escreveu:
>> > The gschem logic symbols seem to have embedded Vcc and GND
>> > connections (at least the ones that I was looking at). Since I am
>> > working on a board that has 3.3V and 5V logic this is a problem.
>> >
>> > I created a script that takes a logic symbol with embedded Vcc and
>> > GND nets and creates (1) a new symbol with the power nets removed
>> > and (2) a new symbol with two power pins. My plan is to place
>> > power symbols (and decoupling caps) for each IC in a separate
>> > section of my schematic.
>> >
>> > Since many symbols contain the same pinout for power pins the
>> > power pin symbol is a symlink to a generic symbol. The new symbol
>> > without power pins have a _np suffix. The symbol containing the
>> > power pins has a _pwr suffix.
>>
>> I allways used that way. I redrawed all my symbols to fit that
>> standard. Unfortunatelly, there are a lot of people that dislikes
>> that way. IMHO all the pins used in a component must be showed on
>> the schematic, no matter what the pin is. I have a lot of boxes with
>> power pins, and its a good way to place decoupling caps.
>> When you mix analogic components with digital, its common to have,
>> for example, two 5V, one for the digitals and another for the
>> analogic. If you use the embedded pins, they will all use only one
>> power supply. And when routing the board, its better to know exactly
>> where all the connections go taking a look at the schematic.
>
>FWIW, I wrote a blurb about this question for the wiki a couple of
>weeks ago.  Here it is:
>
>http://geda.seul.org/dokuwiki/doku.php?id=geda:faq-gschem#what_should_
>i_do_about_power_pins_on_my_symbolsmake_them_visible_explicit_or_invis
>ible_implicit
>
>Stuart

And your article in Circuit Cellar just walked in the door.  I'll have 
to read that one carefully & see if this old fart can ken it.  At first 
glance, good writing!

-- 
Cheers, Gene
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