About undocumented signal length
mulfycrowh , 01-11-2022, 04:30 AM
Hi everyone,
Sometimes signal length is no more documented.
For example, I fully designed the differential pair GBE1 and applied length matching.
I got the information "Signal Length" and everything is OK.
I am working now on the differential pair GBE0.
I notice that I lost the information "Signal Length" for GBE1 : it was replaced by "n/a".
What are the main reasons for such issue ?
Thanks.
Sometimes signal length is no more documented.
For example, I fully designed the differential pair GBE1 and applied length matching.
I got the information "Signal Length" and everything is OK.
I am working now on the differential pair GBE0.
I notice that I lost the information "Signal Length" for GBE1 : it was replaced by "n/a".
What are the main reasons for such issue ?
Thanks.
WhoKnewKnows , 01-11-2022, 09:09 AM
Are those nets routed yet? I imagine it will indicate na or something similar if the nets aren't routed.
Otherwise, it appears all of these nets belong to a net class, but perhaps they don't all belong to a length matching class?
This sort of thing happened to me more than once when I used X-signals to match trace lengths. I set it all up, tune all of the tracks, then come back to it a couple weeks later an it shows stuff like this instead of the tracks' lengths. I usually have to delete all of the X-signals stuff and set it up again.
When I asked about this here, Robert said he suspected it happens when the user sets up X-signals, then updates Altium while working on the project, then goes back to use X-signals again.🤷
Otherwise, it appears all of these nets belong to a net class, but perhaps they don't all belong to a length matching class?
This sort of thing happened to me more than once when I used X-signals to match trace lengths. I set it all up, tune all of the tracks, then come back to it a couple weeks later an it shows stuff like this instead of the tracks' lengths. I usually have to delete all of the X-signals stuff and set it up again.
When I asked about this here, Robert said he suspected it happens when the user sets up X-signals, then updates Altium while working on the project, then goes back to use X-signals again.🤷
mulfycrowh , 01-12-2022, 02:00 AM
Those nets are routed and are shown as "na".
Those nets belong to differential pair class.
It is disturbing.
Those nets belong to differential pair class.
It is disturbing.
mulfycrowh , 01-12-2022, 02:12 AM
I'm done with the routing before adding polygon pours.
As you can see, the differential pair GBE0 is not documented. GBE1 is documented.
As you can see, the differential pair GBE0 is not documented. GBE1 is documented.
mulfycrowh , 01-12-2022, 02:23 AM
More disturbing, I also notice that both differential pair classes vanish: Ethernet_Diff_0 and Ethernet_Diff_1.
It is not the first time !
It is not the first time !
mulfycrowh , 01-12-2022, 02:27 AM
When I go to PCB > Differential Pairs Editor, Average Length is documented for both pairs.
Longest Signal Length is only documented for Ethernet_Diff_1.
Longest Signal Length is only documented for Ethernet_Diff_1.
robertferanec , 01-14-2022, 07:34 AM
I never fully found out when altium does that. Especially when I open older projects, often this happen ... sometimes helps to redraw the track (or part of the track) but sometimes I can't make it work.
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