S12ZVC CAN PHY

[xiaohui200808]

Hello 

      Iam now  using S12ZVC .My problem is when Busoff occured . CANerror interrupt could  happen .but somtimes when I deal the the  CANerror interrupt .It will enter CANerror interrupt again .The following codes is all right  in Demo  board and in 10 percents of  my boards .But 90 percents of  my boards  will enter CANerror interrupt again and again when busoff happened(use the following codes).  I could not sove the problem 

Is there any  points to taken when deal MSCAN with the CAN PTY ,I just  use  CP0CR_CPE = 1;CP0CR_SPE = 1; 

Other Registers about CAN PTY need  care.

Original Attachment has been moved to: S12ZVC_Bus_off.zip

[RadekS]

Hi xiaohui,

According to your description, it rather looks like some hardware issue or problem with CAN timing.

Do you really want to communicate at 100kbit/s? The standard is 125kbit/s.

The generated PE code configure bit rate with a big error.

BTW: I would like to recommend use external oscillator as the clock source for MSCAN module instead of bus clock (your case).

When I select 4MHz external oscillator as the clock source, the PE do not offer me any configuration for 100kbit/s bitrate.

The CAN PHY slew rate influences propagation delay and this way also ideal CAN bitrate configuration.

For such low bitrates, I would like to recommend for example CAN Physical Layer slew rate 6 (CPCR_SLR2-0 = 0b110).

I hope it helps you.

Have a great day,
Radek

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