JPS56101699A - Ram fault diagnostic system - Google Patents

Ram fault diagnostic system

Info

Publication number
JPS56101699A
JPS56101699A JP325780A JP325780A JPS56101699A JP S56101699 A JPS56101699 A JP S56101699A JP 325780 A JP325780 A JP 325780A JP 325780 A JP325780 A JP 325780A JP S56101699 A JPS56101699 A JP S56101699A
Authority
JP
Japan
Prior art keywords
addresses
data
ram
specific
defective
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
JP325780A
Other languages
Japanese (ja)
Inventor
Masaki Murakami
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.)
Meidensha Electric Manufacturing Co Ltd
Original Assignee
Meidensha Electric Manufacturing Co Ltd
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 Meidensha Electric Manufacturing Co Ltd filed Critical Meidensha Electric Manufacturing Co Ltd
Priority to JP325780A priority Critical patent/JPS56101699A/en
Publication of JPS56101699A publication Critical patent/JPS56101699A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C29/00—Checking stores for correct operation ; Subsequent repair; Testing stores during standby or offline operation
    • G11C29/04—Detection or location of defective memory elements, e.g. cell constructio details, timing of test signals
    • G11C29/08—Functional testing, e.g. testing during refresh, power-on self testing [POST] or distributed testing

Landscapes

  • For Increasing The Reliability Of Semiconductor Memories (AREA)
  • Tests Of Electronic Circuits (AREA)
  • Techniques For Improving Reliability Of Storages (AREA)

Abstract

PURPOSE:To improve the reliability of system while making it possible to assign defective RAM easily by writing data to specific bits of specific addresses and complementary numbers in all the remaining addresses, and by comparing write and read data of all addresses with each other. CONSTITUTION:A plurality of RAMS 31-3n connected to microcomputer 1 via bus line 2 and under the control of software, defective RAM is detected by using a checking program. Then, ROM4, when an abnormal address is detected, finds memory chip coordinates by referring to indexes to assign defective RAM, and consequently the recovery of defective RAM is facilitated. For a diagnosis, data are written to specific bits of specific addresses of RAM, and complementary numbers of the data are written to all the remaining addresses; and the data are read out of all addresses and compared with the write data to check coincidences. This comparison is made over all bits of the memory address space. This method takes a long time for the comparison, but facilitates the asignment of defective RAM, which is replaced, improving the reliability of the system.
JP325780A 1980-01-14 1980-01-14 Ram fault diagnostic system Pending JPS56101699A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP325780A JPS56101699A (en) 1980-01-14 1980-01-14 Ram fault diagnostic system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP325780A JPS56101699A (en) 1980-01-14 1980-01-14 Ram fault diagnostic system

Publications (1)

Publication Number Publication Date
JPS56101699A true JPS56101699A (en) 1981-08-14

Family

ID=11552409

Family Applications (1)

Application Number Title Priority Date Filing Date
JP325780A Pending JPS56101699A (en) 1980-01-14 1980-01-14 Ram fault diagnostic system

Country Status (1)

Country Link
JP (1) JPS56101699A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6127000A (en) * 1984-07-17 1986-02-06 Fujitsu Ltd Inspection method of ram

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4940639A (en) * 1972-08-23 1974-04-16
JPS5358733A (en) * 1976-11-08 1978-05-26 Nec Corp Memory access system
JPS54152929A (en) * 1978-05-24 1979-12-01 Fujitsu Ltd Fail category bit map display system of lsi memory

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4940639A (en) * 1972-08-23 1974-04-16
JPS5358733A (en) * 1976-11-08 1978-05-26 Nec Corp Memory access system
JPS54152929A (en) * 1978-05-24 1979-12-01 Fujitsu Ltd Fail category bit map display system of lsi memory

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6127000A (en) * 1984-07-17 1986-02-06 Fujitsu Ltd Inspection method of ram
JPH0346920B2 (en) * 1984-07-17 1991-07-17 Fujitsu Ltd

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