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JPS5786195A - Protecting circuit for data in memory - Google Patents

Protecting circuit for data in memory

Info

Publication number
JPS5786195A
JPS5786195A JP55160369A JP16036980A JPS5786195A JP S5786195 A JPS5786195 A JP S5786195A JP 55160369 A JP55160369 A JP 55160369A JP 16036980 A JP16036980 A JP 16036980A JP S5786195 A JPS5786195 A JP S5786195A
Authority
JP
Japan
Prior art keywords
data
line
level
address
write pulse
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
JP55160369A
Other languages
Japanese (ja)
Inventor
Nobuaki Fujii
Tetsujiro Azuchi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Telegraph and Telephone Corp
Original Assignee
Nippon Telegraph and Telephone 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
Application filed by Nippon Telegraph and Telephone Corp filed Critical Nippon Telegraph and Telephone Corp
Priority to JP55160369A priority Critical patent/JPS5786195A/en
Publication of JPS5786195A publication Critical patent/JPS5786195A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F12/00—Accessing, addressing or allocating within memory systems or architectures
    • G06F12/14—Protection against unauthorised use of memory or access to memory

Landscapes

  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Storage Device Security (AREA)

Abstract

PURPOSE:To prevent data in a random access memory from being erased owing to the runaway of a program itself, by protecting the data in the random access memory corresponding to every address. CONSTITUTION:In loading mode, a mode line 5 and a reset line 6 are held at levels H, and an address specified by an address line 12 is used to write data from a data bus 29 in an RAM1 and a 1 is written from a data input line 10 in control memory 2. Then, data from the RAM1 is written in the corresponding address of the control memory 2 to set writing inhibition. In work mode, the mode line 5 is held at a level L and the reset line 6 stays at the level H; and a write pulse control circuit 3 exercises control to send a write pulse to a write pulse input line 8 when the data has the level L, but to send no write pulse when the data has the level H.
JP55160369A 1980-11-14 1980-11-14 Protecting circuit for data in memory Pending JPS5786195A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP55160369A JPS5786195A (en) 1980-11-14 1980-11-14 Protecting circuit for data in memory

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP55160369A JPS5786195A (en) 1980-11-14 1980-11-14 Protecting circuit for data in memory

Publications (1)

Publication Number Publication Date
JPS5786195A true JPS5786195A (en) 1982-05-29

Family

ID=15713479

Family Applications (1)

Application Number Title Priority Date Filing Date
JP55160369A Pending JPS5786195A (en) 1980-11-14 1980-11-14 Protecting circuit for data in memory

Country Status (1)

Country Link
JP (1) JPS5786195A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS601301U (en) * 1983-06-06 1985-01-08 株式会社　力王 underground

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS601301U (en) * 1983-06-06 1985-01-08 株式会社　力王 underground

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