PURPOSE: To obtain a device which is capable of changing easily a part of its function from the outside and is suitable for conversion to an LSI, by providing a register which is capable of setting data from the outside, a selecting circuit for outputting an output control signal by an instructing signal from the outside, or the like.

CONSTITUTION: A register which is capable of setting data from the outside, and a selecting circuit for outputting an output control signal by an instructing signal from the outside, etc. are provided. For instance, the next state Y is generated from the present state X by a logical circuit Y(X), and also an output control signal Z is generated from the state X by a logical circuit Z(X). Subsequently, the final output control signal Z is generated by selecting one of output signals of the logical circuit Z(X) and output control signal registers REG11W13 basing on a selection instructing signal SEL1 from the outside by a selecting circuit MPX1. Next, the final next state signal Y is generated by selecting one of output signals of the logical circuit Y(X) and next state signal resisters REG21W 23 basing on a selection instructing signal SEL2 by a selecting circuit MPX2.