S32K144_CAN_BUSOFF

LzdOo — Wed, 25 Jun 2025 09:01:40 GMT

How can I disable the "CAN BusOff" automatic recovery function and create a "CAN BusOff" mechanism? (Based on SDK 3.0.0)
When "CAN BusOff" occurs, a fault is reported and ten quick recover attempts are made. If the ten quick recover attempts fail, switch to slow recovery.

Is it necessary to shut down all the Tx tasks when "CAN BusOff" occurs?

Re: S32K144_CAN_BUSOFF

Julián_AragónM — Wed, 25 Jun 2025 21:35:45 GMT

Hi @LzdOo,

Please refer to this community post: s32K144 can bus off - NXP Community.

Automatic bus off recovery can be disabled by setting the CTRL1[BOFFREC] bit. If the bit is asserted, automatic recovering from Bus Off is disabled and the module remains in Bus Off state until the bit is negated by the user.

Tx tasks should stop once a bus off fault occurs, as per the CAN 2.0 specification; a bus off unit is not allowed to have any influence on the bus (e.g. output drivers switched off).

You can also refer to this FlexCAN error test example: Example S32K144 FlexCAN TX/RX/Error ISR test S32DS2.2 - NXP Community. Simply short CANH with GND and send message using either SW1 or SW2, FlexCAN enters bus off (error event) and blue LED is ON.

Best regards,
Julián

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S32K144_CAN_BUSOFF

Re: S32K144_CAN_BUSOFF