Oki Electric Industry Co., Ltd.

Kunio Takamatsu

Naoya Kimura

Seiichirou Ishimoto

A semiconductor storage device has a simple control circuit that is added to a general one-port RAM. Taking a port-A clock signal as the reference, the control circuit generates a select signal that selects a port A during the period from elapse of a first predetermined time from the reference timing until a second predetermined time has elapsed and selects a port B during other periods. The control circuit generates a port-A delayed clock signal in the period in which the port A is selected. The control circuit generates a port-B delayed clock signal during the period from elapse of the second predetermined time until a third predetermined time has elapsed. The control circuit generates a conflict monitoring signal during the period from the reference timing until the second predetermined time has elapsed. When a clock signal is supplied from the port B while the conflict monitoring signal is being generated, the port-B delayed clock signal is masked while the conflict monitoring signal is being generated. After the conflict monitoring signal is stopped, the B-port delayed clock signal is generated as a port-B clock signal.

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Fukuoka, Japan

Kunio Takamatsu