FDCAN monitoring bus when MCU in sleep mode

[Imre]

Is it possible for STM32H5 to monitor the CAN bus when MCU is in sleep mode? Upon CAN bus activity detection, MCU automatically performing the wakeup sequence to be back in normal run mode.

[Issamos · Accepted solution]

Hello @Imre 

Yes, you can configure the FDCAN1 to keep running on sleep mode and use his interruption to wake up from sleep mode. For more information use the RM0492 tables 54,55,56 and 96. (If you are using STM32H503 else you can use the RM0481 but maybe the tables numbers change but still the same idea).

Hope this is helpful. If this answers your questions please check this answer as best answer to be diffused to everyone.

Best regards.

II

[Imre]

Hi Issamos

Thank you for the answer, I understand it and it answers the question. I am used to STM32L4 where bxCAN could be set to sleep along with the MCU and upon CAN bus activity woken up and also the MCU.

For STM32H5 it seems that FDCAN can not be put into a low power state (sleep) when MCU is put to sleep and have the possibility to be woken up upon CAN bus activity.

Kind regards
Imre

[Issamos]

Hello again

Can you give me more details '

Best regards.

II

[Imre]

Yes, more details come.

STM32L4:
It has a low power mode that is able to detect activity on CAN bus.

STM32H5:
It does not have a low power mode, but only a power down mode and in that mode it can not detect activity on the CAN bus.

[Issamos]

I agree with your opinion.

Best regards.

II