FlexCAN RJW in K10P144M100 Reference Manual

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FlexCAN RJW in K10P144M100 Reference Manual

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Jeinstei
Contributor II

Hi-

In the K10 reference manual, it states that the RJW field in the CANx_CTRL1 register is set based on a Resync Jump Width of RJW+1, but in Processor Expert and in our tests, it looks like the Resync Jump Width is equal to the value in the field. Which is right? We're trying to figure out the correct baud rate.

Thanks,

Josh E

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jiri_rezler
NXP Employee
NXP Employee

Hello

 

RJW property hint is not correct. RJW property hint should contain "Number of time quanta is equal to entered value + 1." as is also in "Time segment x" properties. We plan to improve this behaviour, the improvemnt together with CAN calculator functionality should be published in the update2 for the CodeWarrior V10.3. Input values will be in number of time quanta.

Best Regards,

Jiri Rezler

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Jeinstei
Contributor II

Jiri-

Just to confirm, does this mean that the value in the CAN calculator is actual wrong as the calculation is based on a segment size - 1? What I'm seeing on a scope is that with an RJW set in PE as 1, I'm seeing an expected baud rate that is the same as the calculator is showing. Is RJW a maximum value? Or is something else going on?

Thanks

Josh

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jiri_rezler
NXP Employee
NXP Employee

Hello,

“Bit rate” calculation in CAN_LDD is correct, only “Time segment X” and “RJW” parameters range value in component are same as bit field in reference manual (for time quanta value is necessary to add 1) – It is low level access representing register values. “Time segment X” and “RJW” properties  will be in time quanta range  in a new version of CAN_LDD component.

Best Regards,
Jiri Rezler

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