Abstract: A variable delay circuit provides an adjustable delay to a strobe signal. An input latch circuit latches each bit data included in internal serial data by a strobe signal delayed by the variable delay circuit. A delay set unit adjusts a delay amount provided to the strobe signal by the variable delay circuit. While a calibration operation is being executed in which a known calibration pattern is inputted as serial data, the delay set unit statistically acquires output latch data of the input latch circuit, and adjusts the delay amount such that probabilities of occurrence of 1 and 0 becomes a predetermined ratio.

Abstract: A change-point detection circuit 16 extracts a clock signal from serial data, input data. A variable delay circuit provides a delay in accordance with a delay control signal to a reference signal having a predetermined frequency, so that the phase of the reference signal is shifted on the basis of an initial delay. An input latch circuit latches internal serial data by using an output signal of the variable delay circuit as a strobe signal. A phase comparator matches the frequencies of the clock signal and the strobe signal with each other, and generates phase difference data in accordance with a phase difference between the two signals. A loop filter integrates the phase difference data generated by the phase comparator and outputs it as the delay control signal. The phase shift amount acquisition unit acquires a phase shift amount based on the delay control signal, the phase shift amount being based on the initial delay provided to the reference signal by the variable delay circuit.

Abstract: A terminal of a plurality of terminals that is located at the farthest position from a host has a return signal generator section, the return signal generator section transmits a return signal at a timing when data transmitted from the host to the terminals arrives at the terminal located at the farthest position, the return signal is returned to the host successively passing through interfaces of the terminals connected to a data bus, and each terminal originates data to be transmitted from the terminal to the host or from the terminal to a particular another terminal in synchronization with the return signal and delivers the data from the terminals to the host or the terminal in synchronization with the return signal.