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:
May. 30, 1995

Filed:

Dec. 16, 1993
Applicant:
Inventors:

Nobutaka Kitagawa, Kawasaki, JP;

Shigeharu Nakata, Yokohama, JP;

Yasuhiro Ishii, Kawasaki, JP;

Masue Shiba, Tokyo, JP;

Assignee:

Kabushiki Kaisha Toshiba, Kawasaki, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11C / ;
U.S. Cl.
CPC ...
365 96 ; 365 94 ; 365201 ; 365226 ; 365 52 ;
Abstract

The same bit lines are used in common to a fixed data cell array and a memory cell array. The output section of the fixed data cell array is connected to an output circuit, just like the output section of the memory cell array. In response to signal CON supplied from a computer, an array selector examines the states of the arrays and performs switching between the state where one of the arrays can be selected and the state where neither of them can be selected. In the case where an externally-programmable memory, such as an EPROM, is employed, a write control circuit operates with respect only to the memory cell array, and prohibits data from being written in the fixed data cell array. The fixed data cell array is pre-programmed as a nonvolatile memory by programming means different from that used for programming the cells of the memory cell array.


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