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Re: gEDA-user: European symbols?



Den 2011-01-01 18:42:49 skrev kai-martin knaak <kmk@xxxxxxxxxxxxxxx>:

Johnny Rosenberg wrote:

here's a
new try, which I tested several times:

http://ubuntuone.com/p/W8l/

I just looked at 7400-IEC-1.sym. Some comments:

* some lines of invisible text is not on 100 grid.

I took a look myself and you're right. I didn't make those though, since I just modified an existing gate, so I guess they are not on â100 gridâ in the original symbol files either, but I didn't check that yet. I didn't add or modify any invisible text except those very unnecessary (?) author- and license lines. I guess I should remove them entirely.


* the footprint attribute is invisible

Didn't change that either. Why would you like them visible?

* pin labels are invisible

* if pin labels were visible, they'd collide with the box

* pin length is 200 units. IMHO, these lengthy pins result in
awkward artwork, when there is little space on the canvas. This
is of course a matter of taste.

200? Strange. Strange. Looks like 300 to me, except the output pin, which indeed is 200. I didn't change that from the original symbol either, though. Actually, the only thing I changed was the shape of the box, and I added an & sign insideâ


* the slot attribute is invisible. I like to make it visible, so
it is explicitly shown on the schematic and can be edited on mouse
click.

* there is no value attribute --> this attribute is used in the bill of
materials

* the visible string 7400 is simple text. That way, it cannot be edited
in the schematic. In a real circuit it should read 74HC00 or whatever
flavor of TTL logic should be used.

* the supply nets are implicitly given with the net attribute. IMHO,
this approach hides information that should be visible in the
schematic. I prefer to put the power pins in a dedicated 74er
power symbol.

* suggestion: If the symbol complies to a specific IEC norm. How about
a comment, that refers to the specific norm?

* what is the intended use of the attribute device=7400 ?

Don't know, I didn't add that, so it is probably the same as the original symbol.


---<)kaimartin(>---

If it's not too much work, could you modify the 7400 symbol to your likings and then send it back so I can modify the other symbols accordingly?

--
Kind regards

Johnny Rosenberg


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