Purpose of creating Net class

[meet]

Dear Feranec,

In Rex module PCB, i found net classes. but i didn't find a single rule which uses Net class as criteria. For example, DRAM_Bank1, Bank2, Bank,3 are classes. but these classes doesn't govern any rule.

checking all the signals is the only purpose to create classes, while reviewing?

Some times we need to define clearance between one class to another. How did you maintained in Rex module PCB?

i noticed that defining all relevant signal in one class have a purpose to check all signals while reviewing the final layout.

could you please elaborate it.

Regards
Meet

[mairomaster]

Net classes can be useful for many things, not only checking the schematics/layout. They keep your nets well structured - otherwise you will have just a whole bunch of nets. In the PCB panel when doing layout for example, it's very convenient to click on a net class in order to highlight all the signals in this net class. Then you can also quickly see which signals are in this net class, check their length, check if they are routed or not and others. Another thing is that you can use the filter to do advanced selection/operations with net classes. You mentioned the rules yourself. Those are the main things that come to my mind now, but I am sure there are more.

[meet]

Thanks Mairomaster for your reply.
but still i am curious to know how gaps between signal or groups or signals are maintained.

[robertferanec]

I agree with mairomaster's answer. Here are some additions, this may help you:

- Class to class clearance definition: http://www.fedevel.com/designhelp/fo...ce-deifinition
- Altium – How to use xSignals ( in Fly-By, T-Branch + Other useful things ): http://www.fedevel.com/welldoneblog/...useful-things/

PS: iMX6 Rex was designed in Altium with no xSignals, so we didn't really use the rules for classes. However, with xSignals you can use the net classes for example for length matching rules. You can download our open source project called OpenRex and play with the rules: http://www.imx6rex.com/open-rex/

[meet]

Thanks Feranec.

[meet]

hello Feranec...

i followed your suggestion "- Altium – How to use xSignals ( in Fly-By, T-Branch + Other useful things ): http://www.fedevel.com/welldoneblog/...useful-things/"

i would like to say, it is superb.. it was really very nice.