JPH04367045A - Semiconductor storage device - Google Patents

Semiconductor storage device

Info

Publication number
JPH04367045A
JPH04367045A JP14208391A JP14208391A JPH04367045A JP H04367045 A JPH04367045 A JP H04367045A JP 14208391 A JP14208391 A JP 14208391A JP 14208391 A JP14208391 A JP 14208391A JP H04367045 A JPH04367045 A JP H04367045A
Authority
JP
Grant status
Application
Patent type
Prior art keywords
part
storage device
semiconductor storage
bus
security code
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP14208391A
Inventor
Yoshimasa Yoshimura
Original Assignee
Mitsubishi Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Abstract

PURPOSE:To obtain a semiconductor storage device which contains a secret protecting function CONSTITUTION:A memory part 2 is provided together with a security code storage part 5, a collation part 3, and a demultiplexer 4. The parts 2, 3 and 5 are connected to an address bus 6, a data bus 8, and a control bus 7 respectively. Thus an external security code can be inputted to the part 5. The part 3 collates the security code received from the part 5 with an externally inputted code and outputs the collation result as a switch signal 11. A demultiplexer 4 switches the bus 7 toward the part 2, 3 or 5 with the switching signal 11. Thus the external read/write accesses can be permitted and inhibited to the part 2. Thus an outsider can be prevented from the forging and altering actions or a copying action without notice. In such a constitution, the secret security property is extremely improved for a semiconductor storage device.
JP14208391A 1991-06-13 1991-06-13 Semiconductor storage device Pending JPH04367045A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP14208391A JPH04367045A (en) 1991-06-13 1991-06-13 Semiconductor storage device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP14208391A JPH04367045A (en) 1991-06-13 1991-06-13 Semiconductor storage device

Publications (1)

Publication Number Publication Date
JPH04367045A true true JPH04367045A (en) 1992-12-18

Family

ID=15307040

Family Applications (1)

Application Number Title Priority Date Filing Date
JP14208391A Pending JPH04367045A (en) 1991-06-13 1991-06-13 Semiconductor storage device

Country Status (1)

Country Link
JP (1) JPH04367045A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07200287A (en) * 1993-12-16 1995-08-04 Internatl Business Mach Corp <Ibm> Protected program type memory cartridge and computer system using the same
US6230244B1 (en) 1997-06-12 2001-05-08 Oki Electric Industry Co., Ltd. Memory device with read access controlled by code

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63251879A (en) * 1987-04-08 1988-10-19 Hitachi Ltd Portable information processor
JPH02287742A (en) * 1989-04-28 1990-11-27 Kokusai Electric Co Ltd Nonvolatile memory with storage protecting function
JPH03113656A (en) * 1989-09-28 1991-05-15 Mitsubishi Electric Corp Semiconductor storage device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63251879A (en) * 1987-04-08 1988-10-19 Hitachi Ltd Portable information processor
JPH02287742A (en) * 1989-04-28 1990-11-27 Kokusai Electric Co Ltd Nonvolatile memory with storage protecting function
JPH03113656A (en) * 1989-09-28 1991-05-15 Mitsubishi Electric Corp Semiconductor storage device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07200287A (en) * 1993-12-16 1995-08-04 Internatl Business Mach Corp <Ibm> Protected program type memory cartridge and computer system using the same
US6230244B1 (en) 1997-06-12 2001-05-08 Oki Electric Industry Co., Ltd. Memory device with read access controlled by code

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