[PCB_FORUM] Re: Propagation Rules driven from Schematic to Allegro

Michael, 
 
Thanks. That pesky "0" is what was causing my problems. Interesting that
"null" and "0" is treated so differently in this case.
 
Tony 

________________________________

From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Michael
Catrambone
Sent: Friday, April 25, 2008 4:31 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: Propagation Rules driven from Schematic to
Allegro



Hi Tony,

 

The DIFFP_PHASE_TOL value is treated as an absolute number so 25 mils
indicates that one net in the pair cannot be longer than 25 mils to the
other.

 

With RELATIVE_PROPAGATION_DELAY by leaving the Delta field blank will
give 25 mils absolute match and if the Delta field contains any other
number it will be treated as a +/- Tolerance. (Delta field is after the
S: in the example below)

            RELATIVE_PROPAGATION_DELAY GRP:G:L:S::25        -->  Means
the nets in the group should match to 25mils.

            RELATIVE_PROPAGATION_DELAY GRP:G:L:S:0:25      -->  Means
the nets in the group should match to +/-25mils which may yield up to 50
mils between nets.

 

I just wanted to clarify the Rel Prop Delay value settings.

Hope this helps,
Michael Catrambone
UTStarcom, Inc.

________________________________

From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Cosentino, Tony
Sent: Friday, April 25, 2008 3:09 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: Propagation Rules driven from Schematic to
Allegro

 

Just be careful because the 25 mil matching property may be +/-25 mils
not 25 mils absolute. I know with the REL_PROP_DELAY approach 25 mils is
really +/- which yields a total match length difference of 50 mils.

 

Thanks

Tony Cosentino

Tekelec

919-460-3656 office

919-414-2083 cell

 

________________________________

From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Michael
Catrambone
Sent: Friday, April 25, 2008 3:15 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: Propagation Rules driven from Schematic to
Allegro
Importance: High

You want to add a DIFFP_PHASE_TOL  <25 mil> to your diff pairs to
control the length between the pairs and not a Rel Prop Delay.  All of
the diff pair rules are easily controlled in Constraint manager and I
would recommend only passing the DIFFERENTIAL_PAIR property to define
your pairs and set everything else in Constraint Manager.

Hope this helps,
Michael Catrambone
UTStarcom, Inc.

________________________________

From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Dale Rasmusen
Sent: Friday, April 25, 2008 1:55 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Propagation Rules driven from Schematic to Allegro

 

Hi all, I was wondering how to do the following...  

 

I have diff pairs that need to have REL_PROP_DELAY GRP:G:L:S::25
properties between P and N signals.. but I also want to place 20 of
these pairs in a group that must adhere to a PROP_DELAY of
L:S:1000:2000.

 

Thus I have P and N constraints as well as a group prop delay
constraint.

 

I'm not sure how to structure these rules for Allegro.  Your help is
appreciated.

 

Thanks,

 

 

Dale Rasmusen

CAD Manager

TEKNOVUS

(707) 665-0400 ext 133

(707) 665-0491 fax

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