Abstract: A semiconductor integrated circuit device includes a semiconductor layer formed on a support substrate so as to be insulated from the support substrate; plural circuit blocks formed in the semiconductor layer so as to be insulated from one another; and at least one pair of power supply terminals provided in connection with each of the circuit blocks to supply power to the respective circuit block. The circuit blocks operate as a whole while connected together in series by successively connecting the power supply terminals of different circuit blocks to one another, and also each of the circuit blocks can operate independently under a state that a voltage is applied between the pair of power supply terminals.

Abstract: A compact input/output processing IC, which reduces the CPU load, to which microcomputer 100, input/output processing IC 200, and various inputs and outputs are connected. Parallel signals are connected to a high-speed input/output buffer and serial signals are connected from communications control circuit 207 via serial communications circuit 206 to SIO 104. To achieve the proper control, data requiring high speed is handled by parallel communications. Serial communications is handled by shift registers, first bit of each being connected to the last bit of the other, to form a loop, with instruction and input/output data from the CPU exchanged simultaneously, thereby achieving efficient processing. This achieves better organization of the communications for input/output processing, enabling both better control and a compact hardware design.