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Javier1
Principal
Feb 25, 2021 4:46 PM UTC
Solved

weird CANBUS signal shape, different voltages within the same frame?

Question for the Hardware-wise ones:

When probing canH and canL with my isulated oscilloscope i get the following signal:

0693W000007ZV7pQAG.pngdifferent voltage levels inside the same frame??!.

Notice how the ACKs are always higher voltage also

It doesnt happen always but every time is just half frame 600mv difference

0693W000007ZV8sQAG.png 

No idea of what is going on, im using exclusively ifx1050gvio transceiver, the bus has its proper EOL and is about 3m long, populated with 4 nodes and a master.

This topic has been closed for replies.
Javier1
Javier1Best answer
Principal
Jun 2, 2021 7:18 AM UTC

The issue was related with bad clocks.

I was using Resonators instead of XTALS. (they proved to be even worse than internal HSI clock)

this was making CANBUS sync to fail specially when ACKing every frame

hit me up in https://www.linkedin.com/in/javiermuñoz/

1 reply

Javier1
Javier1AuthorBest answer
Principal
Jun 2, 2021 7:18 AM UTC

The issue was related with bad clocks.

I was using Resonators instead of XTALS. (they proved to be even worse than internal HSI clock)

this was making CANBUS sync to fail specially when ACKing every frame

hit me up in https://www.linkedin.com/in/javiermuñoz/