In STM32F407, I have set bxCAN with CAN_MCR.ABOM=0 and CAN_MCR.NART=0.
With the bus lines after transceiver (PHY) left open, after trying to transmit, transmitter transmits continuously forever, with CAN_ESR.LEC=0b011 for Acknowledgement Error (which is expected, as there's no other party on the bus to acknowledge), and CAN_ESR.BOFF=0.
Also, CAN_ESR.TEC appears to permanently read 0x80.
Why?
Error management subchapter in RM0090 says:
The Bus-Off state is reached when TEC is greater than 255, this state is indicated by BOFF
bit in CAN_ESR register. In Bus-Off state, the bxCAN is no longer able to transmit and
receive messages.
[...]
If ABOM is cleared, the software must initiate the recovering sequence by requesting
bxCAN to enter and to leave initialization mode.
Can somebody please comment/explain this behaviour?
Thanks,
JW
