The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Dec. 22, 1992

Filed:

Sep. 19, 1990
Applicant:
Inventors:

Hiromi Kawashima, Yokohama, JP;

Yoshinori Tsujimura, Kawasaki, JP;

Assignees:

Fujitsu Limited, both of, JP;

Fujitsu VLSI Limited, both of, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11C / ;
U.S. Cl.
CPC ...
36518907 ; 365195 ; 365228 ;
Abstract

Where an electrically erasable and programmable non-volatile semiconductor memory element (EEPROM cell) for storing a setting and releasing of the software data protection has already been set in the logic state designating the software data protection setting state, and operation of setting the logical state designating the software data protection setting is not applied to the EEPROM cell even if the address and data for setting the software data protection is input. Further, where the logic state designating the releasing of the software data protection has been set in the electrically erasable and programmable non-volatile semiconductor memory element, the operation of setting the logical state designating the release of the software data protection is not set to the EEPROM cell, even if the address and the data for releasing the software data protection is input.


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