[PCB_FORUM] Re: symbols form libraries and BRD database

  • From: Michael Catrambone <mcatramb@xxxxxxxxxxx>
  • To: icu-pcb-forum@xxxxxxxxxxxxx
  • Date: Sat, 18 Sep 2010 16:04:18 +0000 (UTC)


Hey Bill, 



I agree with you. 



I believe what he is seeing is the result of creating a clipboard from a 
database which used an older version of the library then importing it into a 
new database which has has used a newer version of the library.  The resulting 
symbols that come in thru the clipboard file will be skeleton symbols with 
exploded pins built based off the clipboard file that may not match the symbols 
currently placed in the design even if they have the same name.  This is the 
only way I have ever seen what is described. 


  

Mike 

----- Original Message ----- 
From: "Bill Zembek" <billz@xxxxxxxxxxx> 
To: icu-pcb-forum@xxxxxxxxxxxxx 
Sent: Friday, September 17, 2010 1:15:04 PM 
Subject: [PCB_FORUM] Re: symbols form libraries and BRD database 




Hi, 

I have been reading the responses and took the time to do some testing. I can 
not confirm the behavior 

you have described. 



I took a board and placed an IC. Saved the board and copied the footprint to a 
new directory (my working directory) and replaced the padstack 

and saved it with the same name. 



I then read in a new netlist and placed another part with the same footprint 
name as the one placed. The part placed was the one copy in the brd database 

and not the new one. 



This is the behavior I have always seen. 



If you can provide a test case demonstrating this behavior you should submit it 
to Cadence. 



Regards, 


Bill Zembek 

Technical Support – Allegro Specialist 



EMA Design Automation, Inc. 

225 Tech Park Drive 

Rochester , New York 14623 

Phone 585-334-6001 Opt 5 

Fax 585-334-6693 

www.ema-eda.com 

www.timingdesigner.com 



Cadence ® OrCAD ® Capture CIS with Digi-Key ® Integration 

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From: icu-pcb-forum-bounce@xxxxxxxxxxxxx 
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of William Billereau 
Sent: Wednesday, September 15, 2010 5:03 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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