Apparatus and method for operating a master-slave system with a clock signal and a separate phase signal

A master-slave system includes a clock and phase signal generator to produce a clock signal at a given frequency and a phase signal at an effective frequency, where the phase signal may or may not be periodic and has an effective frequency less than the given frequency. A clock line is connected to the clock and phase signal generator to carry the clock signal. A phase line is connected to the clock and phase signal generator to carry the phase signal. The phase line includes a phase-to-master path to carry a phase-to-master phase signal and a phase-from-master path to carry a phase-from-master phase signal. A master device is connected to the clock line and the phase line. A data bus is connected to the master device. A slave device is connected to the data bus, the clock line and the phase line. The slave device processes data on the data bus in response to the clock signal and the phase signal.