How to get the STM32F7 CAN peripheral out of passive mode

[NWalk]

I have several slave devices devices hanging off connected to an STM32F7. When I power cycle the slave devices, the REC field in the ESR is greater than 128, causing the EPBF bit (in passive mode) to also be set. If I reload the chip, ESR is cleared and CAN communications are OK. I could not figure out a way to clear the ESR otherwise.

[Uwe Bonnes]

Are you sending messages while the slaves are powered off? Then the master does not see an ACK for the message, incrementes the error counter and tries to resend until 128 errors have happened. Make sure at least one other device on the bus is powered when you send messages