问题
I am aware of the way CAN bus does its arbitration. In a nutshell the CAN node ID having more '0' 's in its indentifier wins the rite to transmit on the bus and the rest of contending nodes back off.
But i dont find any details of how long the backed out node waits before re-trying to win the bus back. I consulted a few sources but still cant find the answer. Any experimental evidence for this ?
Bosch CAN
Introduction to the Controller Area Network
回答1:
It is free to try again after the winning frame has been transmitted and no dominant bit has been found in the "intermission field" at the end of the CAN frame. You'll probably find a formal definition of this if you search the spec for "intermission field", see for example 3.1.5 of the old (obsolete) Bosch spec you linked.
The important part here is to realize that every CAN controller listens to every single frame, even if it isn't interested in it. This is how you achieve collision avoidance, rather than collision detection.
回答2:
As mentioned in the Bosch CAN specification document all the CAN nodes can start to send pending frames when Bus Idle condition occurs (no dominant bit found on the bus). During the intermission period in the Interframe spacing no node can transmit (Overload frames can be transmitted but not Data or Remote frames). CAN nodes must wait for 3 recessive bits during this period. All nodes can start transmitting right after this intermission period.
If multiple nodes start at once after intermission period then the lowest identifier frame will win the arbitration. If the remote and data frames (both have same identifier) from different nodes start then the data frame will win the arbitration.
回答3:
I agree with the answers above but i was looking for more mathematical analysis of the CAN bus timings. I found this excellent lecture notes : Time analysis of CAN messages . Chapter 3
来源：https://stackoverflow.com/questions/36689307/can-bus-arbitration-backoff-time