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 People having trouble with vz bouncing email to me should add the word 'online' between the 'verizon', and the dot which bypasses vz's stupid bounce rules. I do use spamassassin too. :-) Yahoo.com and AOL/TW attorneys please note, additions to the above message by Gene Heskett are: Copyright 2006 by Maurice Eugene Heskett, all rights reserved.