50.7.5 Low-Power Mode
In Low-power mode, the CAN controller cannot send or receive messages. All mailboxes are inactive.
In Low-power mode, the SLEEP signal in CAN_SR is set; otherwise, the WAKEUP signal in CAN_SR is set. These two bits are exclusive except after a CAN controller reset (WAKEUP and SLEEP are stuck at 0 after a reset). After power-up reset, the Low-power mode is disabled and the CAN_SR.WAKEUP bit is set only after detection of 11 consecutive recessive bits on the bus.