FEDEVEL
Platform forum

mulfycrowh , 12-08-2021, 03:15 PM

Hi,

I would like to check that both lines (_N and _P) for each differential pair of my design are within a tolerance.
I created a rule (MatchedLengths_InPairs).
I applied it to Diff Pair Class > All Differential Pairs.
I gave a tolerance of 0.254 mm "Within Differential Pair Length".

I am pretty sure that the differential pairs of my design do not match with the rule.
I read that the not matching pairs should be highlighted in yellow on the Differential Pairs Editor.

Before modifying the tracks, it would be great to check what is wrong.

Thanks.

mulfycrowh , 12-10-2021, 10:06 AM

Any idea ?

WhoKnewKnows , 12-10-2021, 08:18 PM

What's the question? Perhaps it's, Why are the differential routes not following the design rules? Or, why aren't the routes that don't follow the design rules marked as rule violations?

On the latter, you may want to look to the rules editor and confirm that the rule is enabled. If there are more than one rule in the same class, make sure the priority of the rules are set so that one rule doesn't interfere with another. You may want to look to the design rule check dialog and make sure that checking the rule(s) in question is enabled.

mulfycrowh , 12-11-2021, 01:40 AM

Hi,

The question is how to see that the design does not comply with differential pairs matched lengths ?
I have 2 rules in that section.
I set priority 1 for InPairs and priority 2 for BetweenPairs.

But I don't still see any warning.
Any idea ?

robertferanec , 12-11-2021, 02:11 AM

the rule within diff pair should work. As @WhoKnewKnows suggested, it may be something in your specific rule setting. Maybe try to disable other rules, enable only that one and see if it works ... if not investigate why. Sometimes the rule expression is not set correctly.