iMX RT-1064 CAN3 - minimal module clock

steffenrose · ‎06-14-2023

Currently I use a MIMXRT1064-EVK and want to use the following setting:

Bittiming - all real values, not register values - for 40MHz:

Arb 500k:

Data 2000k:

From the configuration I use currently:

MB 0 - for TX errata

MB 1 / MB 2 - RX

MB 13 - TX

For my first tests it works. But I'm unsure about the requirements of Table 45-18.

Can you please check, if my clock of 40MHz is good or if I have to go to 80MHz?

Additional question:

Is my register value FLEXCAN_MCR_MAXMB(13) right for the maximum on this controller and my requirements?

Thank you

Steffen

kerryzhou · ‎06-19-2023

Thanks a lot for your trust.

I am so sorry for the later reply, as a lot of cases overwhelming me, that I just find your case today.

1. About the CAN module clock for 40M or 80Mhz

I don't think this is must, if 40Mhz already works, you can use it, don't need to change 80Mhz.

In fact, just a divider.

2. Is my register value FLEXCAN_MCR_MAXMB(13) right for the maximum on this controller and my requirements?

To the MB, The mailbox system consists of a set of 64 Message Buffers (MB).

If you need the 14MB, I think you can fill the 14 as the MAXMB number.

Wish it helps you!

If you still have questions about it, please kindly let me know.

Best Regards,

kerry

steffenrose · ‎06-19-2023

Thank you for your answer to question 1.

For question 2 - I don't understand.

We developp a communication stack and our customer set the requirements.
So I want to configure the possible maximum.

I understand table 45-25, that I have a max of 7 MB with 64Byte payload per RAM block.
So with 2 RAM blocks I can have a max of 14MBs.

Can I configure more, if needed?

Thank you.

Steffen

kerryzhou · ‎06-20-2023

Your understanding is correct.

To the 64Byte payload, the max is 14 MBs, this is the detail situation: You can't see larger.

Wish it helps you!

Best Regards,

kerry