CAN - bus off error recovery

Question

I am still fairly new to CAN bus and working to understand the bus recovery. The MSCAN documentation reads that once a node enters bus-off it "will become error active again after counting 128 occurrences of 11 consecutive recessive bits on the CAN bus". I am trying to confirm that this is not 128 consecutive occurrences.

I believe that it is not consecutive, since the documentation does not read that way for the 128 occurrences, yet states explicitly for the 11 consecutive recessive bits.

I have also found the following post that states:

If that were not the case then a node with a defective receiver would try to send, go bus off, then go bus on again and try to send thereby using 100% of the bus. The 128 * 11 makes it possible for 128 other messages to sneak through while this defective node goes through its bus on/off cycle.

Therefore it would seem that it is understood that it is 128 nonconsecutive occurrences of 11 consecutive recessive bits.

Is there further confirmation of this understanding?

Answer 1

I believe you are correct in understanding that the bus is looking for nonconsecutive occurrences; I read through the Bus Off Error Recovery portion of this CAN example. The bus is looking for a total of 128 occurrences in total to pass before recovering, not necessarily in a consecutive sequence.