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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:


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

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

* 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.


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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