its from Sleep Mode. If there are new transmission requests from either the TX FIFO or the TX High Priority Buffer when the CAN Controller is in Sleep Mode, these requests are not serviced, and the CAN Controller continues to remain in Sleep Mode. Interrupts are generated when the CAN controller enters Sleep mode or Wakes up from Sleep mode.</li>
<li><b>Loop Back Mode</b>: In Loop Back mode, the CAN controller transmits a recessive bit stream on to the CAN Bus. Any message that is transmitted is loop backed