[TWAI-3.13.1] Receive Error Counter (REC) Is Allowed to Change Whilst in Reset Mode or Bus-off Recovery

Affected revisions: v0.0 v1.0 v1.1 v3.0 v3.1

Description

When the TWAI controller enters reset mode (e.g., by setting the RESET_MODE bit or due to a bus-off condition) or when the TWAI controller undergoes bus-off recovery, the REC is still permitted to change. This can lead to the following cases:

  • Whilst in reset mode or bus-off recovery, a changing REC can lead to the error status bit changing which in turn could trigger the error warning limit interrupt.

  • During bus-off recovery, an REC > 0 can prevent the bus-off recovery process from completing.

Workarounds

When entering reset mode, the TWAI controller should set the LISTEN_ONLY_MODE to freeze the REC. The desired mode of operation should be restored before exiting reset mode or when bus-off recovery completes.

Solution

No fix scheduled.