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Re: Library work



let's look on the specs, no offense:

Author: Vesa Solonen 6.10.2008
License: GFDL

Schematic symbol guidelines

-The main dimensional unit (DU) is tied to resistor symbol width. The width includes outline line thickness and keepout.

Resistor symbol dimensions are defined in IEC-617-4 (EN 60617-4) width is 2.5mm, which is approx. 1/10", which is 100 mils. IMO it is measured from one line axe to another. The height is defined 7.5mm, which is approx. 3/10", which is 300 mils. It is called an M like module.

-There must be at least one DU spacing between pins or any other
symbol >feature, like corner. Excluding symbols with width less than 2*DU.

Spacing between pins is defined also in IEC-617-4 (EN 60617-4) as 2*M so it is 5mm, which is approx. 2/10", which is 200 mils.

-Resistors: length 2.2*DU, pins 3*DU

see above, pins are M/2

-Capacitors: plates 0.5*DU apart center to center, plates width 1,25*DU, plates thickness Thick, pins 2*DU. Positive plate in Bold outline.

Plates defined as M/2 center to center, width 2*M, positive marked with "+" one M wide, one M high, placed one M left and one M up from center.

-Transistors: outline ring diameter 2*DU, base-beam length 1.33*DU in Thick, emitter arrow in Bold. Pins in C(0.5, 1.5), E(0.5, -1.5), B(-1.5, 0) positions taking outline ring centre as origin.

Transistor is defined without circle (except transistor with one electrode connected to the envelope - in this case circle diameter is 4*M).

Base beam is 2*M.

That is said in IEC-617-5 (EN 60617-5).


Vesa Solonen napsal(a):

What's the policy for official libraries? I'd like to enhance them a bit
and also would like to know wether we can agree on 'official' library
style. The style part is probably the most difficult task and my ultimate
goal is to look after possibilities to make dynamically styled schematic
library. I think one of the finest examples is ATMEGA8 symbol, but the
whole library lacks coherency.

For some examples please look at:
http://users.tkk.fi/~vsolonen/kicad/ <http://users.tkk.fi/~vsolonen/kicad/>

How to get dynamic styling? Some ideas will be found in
Symbol_guidelines.txt document and the real implementation would need
adding style tag to the library graphic primitives and support to the
parser. I think the better way of getting there is devising SVG import
system for symbols and just leaving the pin object definitions to kicad
library editor. That way complex gui etc for graphics manipulation would
be external to Kicad (Any good svg editor, like Inkscape). Full blown
internal svg-support might be too heavy with very complex schematics,
would it? At least it would be a whole lot of work.

I might try writing an svg importer in python some time...

SVG import would be really fine way for adding custom logos to layouts.


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