A circuit includes signal conditioner circuitry, level shifter circuitry, and state detector and controller circuitry coupled between the signal conditioner circuitry and the level shifter circuitry. The state detector and controller circuitry includes receiver circuitry and a finite state machine coupled to the receiver circuitry. The finite state machine is configured to detect a first data rate from signals, control operation of the signal conditioner circuitry responsive to detecting the first data rate, and control operation of the level shifter circuitry during a second data rate.