Eagle vs Protel

[Sylvain Munaut]

Hello Robert,



OrCad used to have that but this can create more problems than
desirable. You modify a part and suddenly some of the old schematics
don't work anymore because they pick from that repositoiry when loading.
I like Eagle's approach better and IIRC OrCad is now similar in that
respect. In the end the library has to be part of the schematic.

Well, I'd like a central repository as well. But when the part is
already on a schematic/board, the version that was used at design time
must be stored inside the schematic/board, with a possibility to update
to the latest library version.

That would be nice so that when I decides to make the pads on the SOT23
footprint larger, or change the silkscreen marking, It updates all the
SOT23 in all the library I have.


Sylvain

 

[Joerg]

Hello Sylvain,

Well, I'd like a central repository as well. But when the part is
already on a schematic/board, the version that was used at design time
must be stored inside the schematic/board, with a possibility to update
to the latest library version.

The central repository is possible with most CAD system including Eagle.
It's just a matter of discipline and proper archiving.

That would be nice so that when I decides to make the pads on the SOT23
footprint larger, or change the silkscreen marking, It updates all the
SOT23 in all the library I have.

That is dangerous. Suppose you need a BC847 in a really small footprint,
minimized to cram a lot onto a square inch of space in low power
applications. Then you would use a BAT54 in switcher apps but want a
larger footprint to squeeze out a little more thermal conduct, requiring
a larger foot print. Both are SOT23 but now you would compromise one of
them.

Regards, Joerg

 

[budgie]

Hello Sylvain,


The central repository is possible with most CAD system including Eagle.
It's just a matter of discipline and proper archiving.


That is dangerous. Suppose you need a BC847 in a really small footprint,
minimized to cram a lot onto a square inch of space in low power
applications. Then you would use a BAT54 in switcher apps but want a
larger footprint to squeeze out a little more thermal conduct, requiring
a larger foot print. Both are SOT23 but now you would compromise one of
them.

That's when you create your new SOT23A footprint. You wouldn't believe how many
TO-92 footprints I have now ;-)

 

[Rich Grise, but drunk]

Hello Robert,


OrCad used to have that but this can create more problems than
desirable. You modify a part and suddenly some of the old schematics
don't work anymore because they pick from that repositoiry when loading.
I like Eagle's approach better and IIRC OrCad is now similar in that
respect. In the end the library has to be part of the schematic.



I do have a few quirks with it. Often it won't print. Nada, zilch, no
error message, nothing. Then you have to either reload or
deselect-select the printer and (sometimes) it decides that it will now
print.

Haven't had it crash yet like Ban did. But that doesn't mean it couldn't
happen here as well. So I do save every few minutes.

It's SO EASY to save! Just alt-F-S. It even works in most Linux programs.
I spent a couple of hours once trying to train a guy to use alt-F-S to
save his work - this is the guy who "taught" me Autocad, and the guy
would routinely lose a couple hours' work by screwing something up, or
letting Win2K screw up, and have to go back to his last save. But I
couldn't get him to go alt-F-S.

He doesn't work here any more - turns out he was merely glib.

Cheers!
Rich

 

[Rich Grise, but drunk]

Well, I'd like a central repository as well. But when the part is
already on a schematic/board, the version that was used at design time
must be stored inside the schematic/board, with a possibility to update
to the latest library version.

That would be nice so that when I decides to make the pads on the SOT23
footprint larger, or change the silkscreen marking, It updates all the
SOT23 in all the library I have.

Sounds like the S/W needs "dependency checking". This has always been a
bugaboo with upgrades, whether to dll's or .so libraries.

Now that I've brought it up, of course, I have no answer other than to
exhaustively go through everything you have, and check for dependencies
before you update _anything_.

Thanks!
Rich

 

[Pig Bladder]

That's when you create your new SOT23A footprint. You wouldn't believe how many
TO-92 footprints I have now ;-)

Betcha I would. It _is_ finite, isn't it? ;-P

 

[budgie]

Betcha I would. It _is_ finite, isn't it? ;-P

Yep, and it even fits into Excel's 15-digit capacity ;-)

 

[The Real Andy]

Hello Sylvain,


The central repository is possible with most CAD system including Eagle.
It's just a matter of discipline and proper archiving.


That is dangerous. Suppose you need a BC847 in a really small footprint,
minimized to cram a lot onto a square inch of space in low power
applications. Then you would use a BAT54 in switcher apps but want a
larger footprint to squeeze out a little more thermal conduct, requiring
a larger foot print. Both are SOT23 but now you would compromise one of
them.

Regards, Joerg

I use Protel. I have a standard set of footprints in a central
repository, which excludes the footprints shipped with protel. With
each project, i generate a library for both schematics and pcbs. I use
the footprints from the central repository to lay the complete board,
then create a library from the board. What components are not in the
central repository are created in the project library then ported back
to teh repository if needed.

The main advantage of keeping all footprints/components with the
project means that it can be taken anywhere. If you dont have your
origonal library, thats fine. Every project I do gets kept in source
control and has a seperate cd/dvd made.

What would be nice it to get some kind of source control that would
allow merging when multiple engineers are working on a project. This
would be virtually impossible, but given a large job with each
engineer having his/her own page...Nice...

 

[Joerg]

Hello Andy,

What would be nice it to get some kind of source control that would
allow merging when multiple engineers are working on a project. This
would be virtually impossible, but given a large job with each
engineer having his/her own page...Nice...

It can be done but often requires another enterprise IT software as a
top layer. At my last company we had that, IIRC it was Agile. This
allowed doc and repository sharing. We didn't fully use it with CAD (we
could have) but we did with the parts master. We even used it across
divisions which were located in different places.

Regards, Joerg

 

[The Real Andy]

A little light trolling isn't bad. 100 layers is an awesome concept.
The most I've ever done is 8.

John

I have seen 12 layers. Used for inductive sensing, so 10 out of the 12
layers were effectively an antenna.

 

[maxfoo]

Thanks guys,

I think eagle is then the way to go, and since I know it quite well and are
very happy with it, it makes the choice just so much easier.

I never used an autoplacement, and based on the comments, I can't justify
the higher expense and learning curve of Protel.

Eagle served me well, and works even on my small Linux box ....

Regards

Wilhelm

Have you looked at http://www.freepcb.com/

Does up to 8 layers and board size up to 60"x60" area.

and is absolutely free with source code GNU

 

[Fred Bloggs]

I have >30 years ...

 

[Fred Bloggs]

You can't understand engineering. That fact is as plain as the dick on
your face.

Crap, I did an ...

 

[keith]

....to figure out how to answer a post? Yep, that's you Bloggs.

 

[Robert Latest]

On Thu, 18 Aug 2005 23:47:08 GMT,

That is dangerous. Suppose you need a BC847 in a really small footprint,
minimized to cram a lot onto a square inch of space in low power
applications. Then you would use a BAT54 in switcher apps but want a
larger footprint to squeeze out a little more thermal conduct, requiring
a larger foot print. Both are SOT23 but now you would compromise one of
them.

You'd actually have two packages, SOT32-SMALL and SOT23-BIG (for
instance), and in the devices you'd create different package variants.

robert

 

[Joerg]

Hello Robert,

You'd actually have two packages, SOT32-SMALL and SOT23-BIG (for
instance), and in the devices you'd create different package variants.

Yes, that would be the proper way to do it. However, deviating from the
mfg suggestions may cause your layouters to pull their hairs out. If you
use external layouters which is the usual scenario out here.

Regards, Joerg

 

[John Perry]

Hello Robert,

Yes, that would be the proper way to do it. However, deviating from the
mfg suggestions may cause your layouters to pull their hairs out. If you
use external layouters which is the usual scenario out here.

Why not just add a -a or -b or some such to your adjusted
package/device, and rename it to delete the qualifier when you put it
into your board-specific library?

John Perry