To reduce the number of gates of a comparing part and costs, to save space and to reduce delay time.

This device is provided with an inversion gate 4 inverting the most significant bit of comparison data 22 with a code from a counter, a gate which is needed conventionally and for code discrimination is made unnecessary by working and setting a comparison reference value 21 from a CPU responding to it, and costs, space and delay time are reduced. Because a discriminating part does not have to be needed any more in this way, the number of gates is reduced, and advantages to reduce costs (about 10% decrease), space (about 40% decrease) and delay time (about 1/2) are obtained.