parameters, flags and various kinds of information therein, a clock 74 for counting a present time, an interval timer 75 (referred to as an IT in the drawings) for counting a value and outputting an interruption signal to the CPU 71 when the interval timer 75 has counted up to a preset time interval value, an external unit interface 76 connected to respective sections 31 to 38 shown in FIG. 2, a