Patent ID: 8363748

Claim:
A two-way communication circuit connected to one end of a cable performing a half-duplex communication, for transferring process data of a higher-order LSI, the two-way communication circuit comprising: a controller register that stores a control signal including switch indication information switching a transmission direction and a reception direction; a buffer circuit that stores the process data from the higher-order LSI and reception data from an opposing circuit device; a cycle management circuit that controls a timing of communication; a control signal management circuit that passes the control signal retrieved from the controller register according to a first timing designated by the cycle management circuit to the buffer circuit when the buffer circuit receives the process data, and that detects and retrieves the control signal from the reception data under a control of the cycle management circuit when the buffer circuit receives the reception data and provides the detected control signal to the controller register; and a transmission and reception circuit that includes receiver and driver circuits, and activates at least one of the receiver and driver circuits according to an indication by the control signal management circuit.