STM32 CAN bus Bus-off recovery question

• STM32 CAN bus Bus-off recovery question
  Posted by Red_Micro on 12 Apr, 2023 23:29
• Using STM32F4 as example, the reference manual says:
  
  

  Quote

  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.
  Depending on the ABOM bit in the CAN_MCR register bxCAN will recover from Bus-Off
  (become error active again) either automatically or on software request. But in both cases
  the bxCAN has to wait at least for the recovery sequence specified in the CAN standard
  (128 occurrences of 11 consecutive recessive bits monitored on CANRX).

  
  So my question is.. if there's already activity on the bus due to other nodes, will the bus-off node ever see those 11 consecutive recessive bits needed to synchronize to the bus?
  
• #1 Reply
  Posted by langwadt on 13 Apr, 2023 00:16
• https://en.wikipedia.org/wiki/CAN_bus#Base_frame_format
  
  ACK delimiter, End-of-frame (EOF),Inter-frame spacing (IFS)    adds up to eleven recessive bits