A method that is for operating a serial protocol interface includes a communication device that is configured to exchange data over a communication link by sending output data on the communication link, and receiving input data on the communication link. The input data is synchronous with a clock signal generated at the communication device and propagated over the communication link. The method also includes initializing operation by sending the output data on the communication link at a first data rate, detecting a signal transition in the input data received on the communication link, and exchanging data over the communication link at a second data rate when the signal transition is detected, the second data rate being higher than the first data, with the exchanging of data at the second data rate synchronized as a function of the signal transition.