STM32H7 CAN FD bit timing when configured as classic can

[VYoun]

Hello,

I need to configure the CAN FD in STM32H7 as classic can. However, I can not understand the bit timing explained in the reference manual.

Can someone please help me to figure out the bit timing for a clock frequency of 42Mhz?

Your help is much appreciated.

Thank you and best regards,

Vouria

[Bouraoui Chemli]

hello @VYoun​ 

Yes you can configure FDCAN as classic CAN.

For the frequency calculation please refer to the reference manual RM0433 Rev7 section 56.4.4 Bit timing.

As you can see in the nominal bit time you must have FDCAN frequency and the baudrate.

Best regards,

Bouraoui

[BSpoe.1]

Why you use 42Mhz as FDCAN kernel clock?

The best way is to use 80 MHz because with this you have the highest resolution for your CAN configuration.

[VYoun]

Hello,

Thank you for your answer, my system is based on this clock, I can not change the system clock because other peripherals are working with this clock.

Best regards,

Vouria