[gta02-core] schematics symbol and drawing style

Rene Harder rehar at saweb.de
Fri Jun 19 19:38:12 CEST 2009

Werner Almesberger wrote:
> Rene Harder wrote:
>> What standard do we use for drawing (e.g. common symbols and style),
>> IEC, ANSI etc.?
> I normally use the choices KiCad comes with. So that is the "European"
> resistor and the triangle for ground. The polarized capacitor (CP) is
> butt-ugly, doesn't look like anything I've seen anywhere else, and
> it's only laziness that has prevented me from changing it.
> Openmoko used the US style quite consistently. I'm fine with that. I
> also don't mind the European style, but I would change the resistor
> to not contain the value inside the symbol, because this often makes
> it hard to read.
I learn today that the ANSI [1] specification also include most of the
IEC symbols, same for logic symbols [2].

After our discussion on IRC yesterday, this is my suggestion.

We go for the traditional Symbols of the ANSI [1] specification because
we already have lots of symbols drawn in this particular style. Also
Openmoko is using this style which makes it easier for us to compare our
drawings to Openmoko's.

Here's my small summery of design rules for the schematics: (collected
from several emails on the list)

- Symbols: traditional US symbols [1], if a symbols is already used in a
  different part of the schematics we'll use the same symbol, not an
  alternative style!!
- Sheet size is A3
- Font size for labels, names etc. is 50mil
- no cross-shaped junctions
  (see [3] for examples, style 3 is the preferred one)
- we'll use Openmoko's component references. Removed symbol
  references will not be reused. New symbols get unique references.

Did i forgot anything or do you have a different opinion?  Please, let
me know.


[1]: ANSI Y32.2-1975 / IEEE Std 315-1975   
(might be only available for IEEE members)

[2]: ANSI/IEEE Std 91-1984 / ANSI/IEEE Std 91a-1991
(might be only available for IEEE members)       

[3]: http://en.wikipedia.org/wiki/File:Schematic_junctions.svg

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