Solution: The baud rate detection principle involves continuously changing the baud rate of the USBCAN device when data is sent on the bus. The receive error flag and receive interrupt flag are monitored until the baud rate matches. Baud rate detection requires a normal physical link for the CAN bus, including correct wiring, terminal resistors, and connections. Additionally, data must be sent above the bus, meaning that nodes above the bus must initiate data transmission to the top of the bus.