[PCB_FORUM] Re: symbols form libraries and BRD database

  • From: William Billereau <William.Billereau@xxxxxxx>
  • To: <icu-pcb-forum@xxxxxxxxxxxxx>
  • Date: Wed, 15 Sep 2010 18:33:39 +0200

Hi Gary.

 

Thanks for your reply.

 

Before making the test you suggest, I just checked that placing a new
part uses the new definition in 16.3.

In fact, no, fortunately.

If I have a c0805 placed and I place a new one, the symbol is the same.

 

The problem is somewhere else:

I think that I first made a "refresh symbols", then the definition was
the new one.

After that, I used a clipboard copy/paste for similar blocks from an old
board which was using an old definition of the C0805.

 

As the symbol definition is written in the clipboard the "pasted"
components also have the old definition.

 

So this behavior can also happen with any release of Cadence..

Very dangerous....

 

                William.

 

 

 

From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Macindoe, Gary
Sent: 15 September 2010 17:37
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: symbols form libraries and BRD database

 

Hey William,

 

I didn't see any replies, so I'll through something out.

 

I have no idea if this will work, but you could try it: Before you
Import Logic, you could temporarily "break" the path to your libraries
(e.g. rename the library directories, edit your env file etc.). If the
libraries can't be found, it can't grab the latest versions of your
symbols.

 

Regards,

 

Gary MacIndoe

Senior PCB Layout Designer

Contract - Kelly Services

Covidien 

EbD R&D

5920 Longbow Drive

Boulder, CO 80301

 

303.476.7458

www.covidien.com

 

From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of William
Billereau
Sent: Wednesday, September 15, 2010 3:03 AM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] symbols form libraries and BRD database

 

Hello All.

 

We have a problem that seems to be appeared in the 16.3 (to be
confirmed).

 

If you start a BRD from another containing some symbols definition,
before this release 16.3, if you added a new component using this symbol
definition Allegro took the definition embedded in the BRD.

If the symbol has been modified on the disk, you had to make a "refresh
symbol" to get the new symbol definition in the BRD file, even for
recent placed components.

 

Now, if you place a component, it seems that Allegro reads the
definition of the symbol on the disk without using the embedded one.

This means that you got in the BRD old symbol definition for components
already placed in the BRD and new symbol definition for newly placed
component.

 

Then, it is not really a problem within Allegro.

We modified a lot of component applying IPC and LPWizard rules.

One of this rule is the symbol origin.

For a 0805 resistor, in the past, our symbol had the origin on pin one.

Now the origin is the body center of the resistor.

 

If you apply a refresh symbol, you have to move all previously placed
resistors, nothing critical, just a little bit annoying.

 

But the main problem is for assembly.

ODB++ output or Fabmaster output contains 2 different kind of 0805 that
are finally the same!

It results in a displacement from the copper for some of them depending
on which definition is taken first:

If the first definition is the body center, then all resistors defined
with origin on pin on have an offset of the half on the right or left,
according to their rotation.

And vice-versa.

 

Is there a way (User Preferences?) to force Allegro to keep the embedded
symbol definition for all new placed components?

 

If not, we will have to implement an automatic refresh for all new
BRD....

 

Thanks in advance.

 

             William.

 

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