Everyone, please pull & test the new "can-txfail-fix" branch. It's up to date and includes the BMW i3 code already. I need to get feedback from users of both can1 (esp32can) & can2/3/4 (mcp2515), as changes had to be made to both drivers. I'll quote from my commit: https://github.com/openvehicles/Open-Vehicle-Monitoring-System-3/commit/c945... Design goals: - any TX can either fail or succeed, the result state is terminal - the respective TX callback is called exactly once - transmissions fail on reaching the error-passive bus state and on message/bus errors while in error-passive state - a failed TX will be aborted (no retries after bus recovery), i.e. will be retried at most 128 times (in error-active phase) - reduce excessive CAN error logging - reduce excessive interrupt load with switched-off buses This results in the application being able to reliably detect a switched-off vehicle bus by the TX callback's success indicator. It also results in frames no longer being held in the TX buffer or added to the TX queue when the bus is switched off. The application can now rely on getting a clean bus state on every reconnect, without any queued old frames to be sent automatically. Secondary benefit from aborting the transmission is, the module doesn't need to handle the load from the continuously triggered CAN error interrupts by retransmission attempts in error-passive state. Reason for this was a) Steve's question on aborting transmissions / flushing the queue and b) my new car now also switching off the bus, with the annoying effect of a frozen can1 every 2-3 days, needing to reboot the module. I'm not sure yet if the freeze issue is solved, but I haven't had it since running these changes on my module. The other issue of the transceivers resending frames queued long ago may have caused all sorts of strange & unrepeatable issues. I remember the VW crew having problems that fell into this category. I've verified the new MCP2515 implementation only on my workbench (with an Arduino as the CAN tester), so real life tests are necessary. Thanks, Michael -- Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal Fon 02333 / 833 5735 * Handy 0176 / 206 989 26