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CAN bus: When does a transmitter give up its transmission attempts
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AndersJ:
A CAN device will retry after a failed transmission.
But,
will it retry forever,
or will it sooner or later give up,
such as when error counters reach their limits?





Niklas:
Up to 16 consecutive transmission attempts before the transmit error counter (TEC) reaches it limit. What happens after that is usually configurable in software. Either wait in silence for a short period of time before the TEC is cleared and enables transmission again. The other option is to accept the failure and go offline, aka bus off.
0xdeadbeef:
IMHO typical (simple) CAN simulators like PeakCAN will send forever without acknowledge. E.g. when sending one (!) wakeup message, it is actually repeated forever until the device to be woken actually wakes up and sends the ACK.
AndersJ:

--- Quote from: Niklas on November 18, 2018, 09:15:36 pm ---Up to 16 consecutive transmission attempts before the transmit error counter (TEC) reaches it limit. What happens after that is usually configurable in software. Either wait in silence for a short period of time before the TEC is cleared and enables transmission again. The other option is to accept the failure and go offline, aka bus off.

--- End quote ---

When the TEC has been cleared and transmission is reenabled,
will the original message be lost forever,
or will it still be in que for another transmission attempt?

Niklas:
It depends on the CAN controller, but most likely the content of the tx buffers is not changed. Only the error handling flags are set.
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