CAN Bus Error Management

[bdesantis]

Posted on April 17, 2015 at 13:06

Hey guys, using the STM32F4 + cube, I setup a CAN device which works good until I play around with disconnecting the CAN bus lines and reconnecting them. Doing so produces bus errors and I am not sure how to handle these errors in a recoverable way?

What I currently do (which is not working)When the CAN Error callback occurs:1) Disable CAN SCE (NVIC_DisbleIRQ(CAN2_SCE_IRQn))2) Set CAN into silent mode (BTR |= CAN_MODE_SILENT)3) Disable the error flag (IER &= ~CAN_IER_ERRIE)4) Set a 5-second timer that is used by the RTOS to try to recover. During this 5-second timer I disable all CAN Rx/Tx handling (bypass my CAN manager task)When the 5-second timer expires, I do this:1) Reset silent mode (BTR &= ~CAN_MODE_SILENT)2) Re-enable the SCE interrupt (NVIC_EnableIRQ(CAN2_SCE_IRQn))3) Re-enable error flagIER |= CAN_IER_ERRIEThe CAN bus does not recover however...Anyone have any ideas as to what else I should be doing?Many thanks! #can-bus

[vromanov]

Posted on April 17, 2015 at 13:46

IMHO you must also check BusOff flag in ESR register (CAN_ESR_BOFF).

[bdesantis]

Posted on April 17, 2015 at 14:12

So I have automatic bus of management (ABOM) turned off at the moment....Should I have turned it on?

Odd thing right now is that the BOFF never gets set even though TEC has exceed the BOFF threshold.....When exactly should I be checking for BOFF?

[Zbigniew Szeliga]

Posted on March 25, 2017 at 14:37

Did you find a solution to have recoverable CAN device? I am working at this right now and I am strugling with finding proper steps to take after

e

rror occurred. When I disconnect bus and try to transmit some frames I get 

HAL_CAN_ERROR_ACK

(HAL version 1.9.0) which is expected, but right now I don't see any other solution except

restarting the whole interface to get it work again after each error occurence.