busoff in can communication

bigdogguru said:

The CAN node which initiates the BUS OFF error condition state is essential isolated from the CAN bus, the remaining CAN nodes operate independently, remaining active, unless of course they too initiate a BUS OFF error condition state.

Although the actual recovery measures taken following a BUS OFF error condition state may largely depend on the specifics of the node's CAN controller, typically an interrupt is triggered and a process of recovery/reinitialization begins.

Often after waiting for the mandatory time period, 128 x 11 bits, an attempt at reinitialization begins.


BigDog

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As per you when error counter of the node is reached to 256 then it will go to bus off condition. After that all nodes which are connected to the bus also goes to
busoff condition.
All nodes off means total busoff.Is it right?

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FvM said:

Mostly wrong.

"Bus off" state is an internal state of a CAN node, which is set only based on the TRANSMIT ERROR COUNT. A transmit error will be detected during transmission if the bus is shorted, blocked by incorrectly acting nodes, or the own bus driver is defective and wrongly detecting a dominant bus state. In this situation, the CAN node stops further transmitting. No specific action of other CAN nodes can be expected.

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