PURPOSE: To increase the number of degrees of freedom of connection between a CPU and external transmission signals without increasing the number of input ports of external transmission signals of a CPU by performing the processing different by the value of a corresponding input port control code storage part.

CONSTITUTION: A processor is provided with a value storage part, an input port control code storage part, and an external transmission signal control part correspondingly to each input port, and each external transmission signal control part refers to the value of the input port control code storage part to update handling of the external transmission signal inputted to the input port. That is, the value of the external transmission signal is written in the corresponding value storage part, and external transmission signals are taken as sequential object signals at the time of specific operation of the processor, and a context dependent interrupt factor is generated when the external transmission signal goes to a prescribed value, and a context independent interrupt factor is generated when the external transmission signal goes to a prescribed value. Thus, the number of degrees of freedom of connection between the processor and external transmission signals is increased.