MICROCOMPUTER

PROBLEM TO BE SOLVED: To save the useless processing of a central processing means(CPU) in the case of error data or the like by stopping the processing of data stored in a 1st storage means(ROM) during the output period of a trigger signal. SOLUTION: An enable signal output means for outputting a NOP enable signal for inhibiting a ROM 6 and a RAM 7 to output data to the CPU 1 in accordance with a trigger signal outputted from a TRG signal output part 21 synchronously with a SYNC signal outputted from the CPU 1 is constituted of AND circuits 22, 23, an inverter circuit 24 and a flip flop(FF) circuit 25. Instead of data stored in the ROM 6, NOP data stored in an NOP data memory 26 can be outputted to the CPU 1 through a data bus 11 in accordance with a TRG signal outputted from a TRG signal output part 21. The CPU 1 can stop the processing of data stored in the ROM 6 during the output period of the TRG signal.