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Multiple classes for DIFF_PAIRS versus single classes for all groups

ntstuart , 05-15-2017, 03:19 PM
I have been going through the course work and noticed a difference between how my Engineer has set up the schematic versus the course work. It seems like we have too many separate classes set up instead of bundling them into simple classes of DIFF_100 and DIFF_85. If there are many Classes added to DIFF_100 for example, isn't this a discontinuity by excluding it from the High Speed rules section? I have attached how it has been set up in my schematic.Both the Engineer and myself are new to Altium but it seems Robert's way of doing it makes more sense. This is a DDR4 design we are doing.
mairomaster , 05-16-2017, 02:00 AM
I don't see much of a point using so many classes as well. If you use them only for setting up the differential pair rules, having a single class for every impedance is working well.
robertferanec , 05-16-2017, 12:32 PM
Signals can be in multiple net classes at once .. you can put them into DIFF100 and also into CSI2 ... so you can use DIFF100 to setup the rules, and you can use CSI2 during layout if you need to see the pins / tracks of the interface.
ntstuart , 05-17-2017, 03:10 PM
I have set up my DDR4 signals using Altium version 16 'xSignals wizard' tool which differs from the way the course suggests. I am guessing you are still using Altium version 14?
robertferanec , 05-17-2017, 03:15 PM
ntstuart , 05-17-2017, 06:03 PM
Which version are you using xSignals? I am using version 17.
robertferanec , 05-17-2017, 06:53 PM
I checked the video and it is Altium 16.1
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