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Question about Flexcan TDCVAL on the S32k148

Question asked by sumityadav on Feb 5, 2019
Latest reply on Feb 8, 2019 by Petr Stancik

Hello,

I am working with the s32k148evb and trying to get CAN FD working with brs enabled. CAN FD works with aribitration phase set to 125Kbps and data phase set to 250kbps. However, when I go higher than 250kbps on the data I start getting errors on the CAN bus. 

BTW: CAN FD with brs disabled works fine at 1mbps. It is only when I enable brs I start seeing errors at any speeds over 250kbps.

After some reading I figured it might have something to do with the transceiver delay compensation. So I enabled it and I used the formulas recommended in the reference manual (Offset=PSEG1+PROGSEG+2) but it still didn't work. I started looking at the TDCVAL and I thought that this value shall measure the same irrespective of the baud rate since it is just measuring the propagation delay through the transceiver. But what I saw was that I was seeing different values with different baud rates. The value got bigger with slower baud rates. Is this expected?

 

What else should I be looking at to make this work?

 

I am using Vector CANoe. Also, the external 8MHz oscillator as my PE clock.

 

Thanks,

Sumit

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