Fujitsu Corporation

Nobuo Ikuta

Yasuo Suzuki

Kouji Ueno

Hiroyuki Fujimoto

Tomohiro Nakayama

Masakazu Kimura

Yutaka Fukutani

Yasuaki Suzuki

Takanori Shiga

Yoshiyuki Fujita

Youji Arayama

Kouji Shishido

A semiconductor integrated circuit device with a copy-preventive function comprises a memory for storing data to be used by users, an input unit for performing various logical operations on at least one input information fed externally and accessing the memory, an output unit for performing various logical operations on the data at the time of supplying the data from the memory, a judging unit for comparing at least one of the state of the input information, the logical state of the input unit, the logical state of the output unit, and the state of data provided by the output unit with specific judgment information and indicating the result of comparison, and a control unit that when the result indicated by the judging unit reveals that the at least one of the states is consistent with a specific state, acts at least on the output unit so as to prevent data stored in the memory from being supplied normally. Due to this configuration, a copy-preventive function can be reformed frequently from both the aspects of software and hardware. Consequently, illegal copying of data can be substantially disabled.

Semiconductor integrated circuit device with copy-preventive function

A read only memory device including: a memory cell array having a plurality of memory cells each storing one of three states; selection means, connected to the memory cell array, for selecting a pair of the memory cells from the memory cell array simultaneously in accordance with an address signal; a first sense amplifier, operatively connected to one of the pair of the memory cells, for producing a three bit output corresponding to the state stored in the one of the pair of the memory cells selected by the selection means; and a second sense amplifier, operatively connected another of the pair of memory cells, for producing a three bit output corresponding to the state stored in the another of the pair of the memory cells selected by the selection means. The device further includes decoder means, connected to the first and second sense amplifiers, for receiving the three bit outputs of the first and second amplifiers and producing a binary three bit output corresponding to the states stored in the pair of memory cells.

Read only memory device having memory cells each storing one of three

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Kawasaki, Japan

Nobuo Ikuta