SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE

PROBLEM TO BE SOLVED: To reduce the effect of output noise by logically outputting data of '0' and '1' alternately by each I/O before outputting normal data of output. SOLUTION: Although a WRB signal which is normal data is inputted to an output buffer circuit 100, in a pseudo output buffer circuit 200, a power supply in the case of an odd I/O and a GND in the case of an even I/O are fixed respectively. In the case of an output state (an output enable signal OE is on a Low level), a signal Q becomes High, and when the circuit 200 is selected, data '1' in the case of an odd I/O and data '0' in the case of an even I/O are outputted. Data of '1' or '0' are alternately outputted from each I/O before the normal data are outputted at the time of output. Thereby, the probability that output data change in each I/O in the same way is reduced, and output noise can be made small.