JPS57117194A - Protection method for data destruction of backup ram at power supply interruption of microcomputer system - Google Patents

Protection method for data destruction of backup ram at power supply interruption of microcomputer system

Info

Publication number
JPS57117194A
JPS57117194A JP56001514A JP151481A JPS57117194A JP S57117194 A JPS57117194 A JP S57117194A JP 56001514 A JP56001514 A JP 56001514A JP 151481 A JP151481 A JP 151481A JP S57117194 A JPS57117194 A JP S57117194A
Authority
JP
Japan
Prior art keywords
power supply
signal
ram
main power
data
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
JP56001514A
Other languages
Japanese (ja)
Inventor
Satoru Hirano
Kenzo Ito
Katsuhiro Oba
Susumu Akiyama
Yuji Hirabayashi
Hideaki Nanba
Shoichi Masaki
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.)
Denso Corp
Original Assignee
NipponDenso 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 NipponDenso Co Ltd filed Critical NipponDenso Co Ltd
Priority to JP56001514A priority Critical patent/JPS57117194A/en
Publication of JPS57117194A publication Critical patent/JPS57117194A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
    • G06F1/26—Power supply means, e.g. regulation thereof
    • G06F1/30—Means for acting in the event of power-supply failure or interruption, e.g. power-supply fluctuations

Landscapes

  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Power Sources (AREA)
  • Techniques For Improving Reliability Of Storages (AREA)
  • Stand-By Power Supply Arrangements (AREA)

Abstract

PURPOSE:To completely prevent the destruction of data, by synchronizing a generated timing of a main power supply interruption detection signal with a control signal of a microcomputer. CONSTITUTION:When a main power supply turns off, a voltage of an inverted input V1 of a comparator 11 detecting the interruption of the main power supply is gradually lowered. If the main power supply is interrupted, an output of the comparator 11 is at high level after a time Ta, and when an ALE signal is generated at a specified timing, an FF12 to generate an RAM chip selection inhibit ing signal is set with the ALE signal in synchronizing with the control signal of a CPU15 to inhibit the chip selection of the RAM. Thus, in the memory instruction, before the data of RAM is effective from the generation of the ALE signal, since the chip selection signal of the RAM is inhibited, the RAM data destruction is completely prevented.
JP56001514A 1981-01-08 1981-01-08 Protection method for data destruction of backup ram at power supply interruption of microcomputer system Pending JPS57117194A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP56001514A JPS57117194A (en) 1981-01-08 1981-01-08 Protection method for data destruction of backup ram at power supply interruption of microcomputer system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP56001514A JPS57117194A (en) 1981-01-08 1981-01-08 Protection method for data destruction of backup ram at power supply interruption of microcomputer system

Publications (1)

Publication Number Publication Date
JPS57117194A true JPS57117194A (en) 1982-07-21

Family

ID=11503586

Family Applications (1)

Application Number Title Priority Date Filing Date
JP56001514A Pending JPS57117194A (en) 1981-01-08 1981-01-08 Protection method for data destruction of backup ram at power supply interruption of microcomputer system

Country Status (1)

Country Link
JP (1) JPS57117194A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5937629U (en) * 1982-08-31 1984-03-09 アンリツ株式会社 Memory content retention circuit
JPS6072012A (en) * 1983-09-28 1985-04-24 Toshiba Corp Battery backup circuit of memory
JPS60238920A (en) * 1984-05-11 1985-11-27 Fanuc Ltd Data holding circuit of memory
JPS6194127A (en) * 1984-10-12 1986-05-13 Mitsubishi Electric Corp Protecting device for service interruption mode

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5937629U (en) * 1982-08-31 1984-03-09 アンリツ株式会社 Memory content retention circuit
JPS6072012A (en) * 1983-09-28 1985-04-24 Toshiba Corp Battery backup circuit of memory
JPS60238920A (en) * 1984-05-11 1985-11-27 Fanuc Ltd Data holding circuit of memory
JPS6194127A (en) * 1984-10-12 1986-05-13 Mitsubishi Electric Corp Protecting device for service interruption mode

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