JPS648422A - Key matrix circuit - Google Patents

Key matrix circuit

Info

Publication number
JPS648422A
JPS648422A JP62164257A JP16425787A JPS648422A JP S648422 A JPS648422 A JP S648422A JP 62164257 A JP62164257 A JP 62164257A JP 16425787 A JP16425787 A JP 16425787A JP S648422 A JPS648422 A JP S648422A
Authority
JP
Japan
Prior art keywords
circuit
signal
inputted
code
outputs
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
JP62164257A
Other languages
Japanese (ja)
Inventor
Tomohiro Nagao
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.)
NEC IC Microcomputer Systems Co Ltd
Original Assignee
NEC IC Microcomputer Systems 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 NEC IC Microcomputer Systems Co Ltd filed Critical NEC IC Microcomputer Systems Co Ltd
Priority to JP62164257A priority Critical patent/JPS648422A/en
Publication of JPS648422A publication Critical patent/JPS648422A/en
Pending legal-status Critical Current

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  • Input From Keyboards Or The Like (AREA)

Abstract

PURPOSE:To shorten the detecting time of a key code and to prevent scanning potential from being shorted by instantaneously switching the inputs and outputs of the 1st and 2nd I/O circuits by the 1st and 2nd I/O control circuits. CONSTITUTION:At the time of inputting a timing signal from a control circuit 17, the 1st I/O circuit 15 outputs a high potential signal to signal lines 1-4 and transfers the input signal to the 2nd I/O circuit 16 to drive the circuit 16 as an input circuit. The signal lines 3, 7 are shorted by depressing a switch 57 and a high potential signal is transferred to the circuit 16 through the signal line 7. A low potential signal is inputted to the circuit 16 through the other signal lines, code '0010' is inputted to the circuit 16 and then inputted to a data switch 14 included in the circuit 17 to decide the depression of the switch. The 2nd I/O control circuit 13 outputs an output signal to the circuit 16 to output said code '0010'. Since the high potential signal is outputted to the signal line 7 and the low potential signal is outputted to the signal lines 5, 6, 8, the code '0010' is inputted to the control circuit 15 and the depression of the witch connected to the signal line 3 is decided.
JP62164257A 1987-06-30 1987-06-30 Key matrix circuit Pending JPS648422A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP62164257A JPS648422A (en) 1987-06-30 1987-06-30 Key matrix circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP62164257A JPS648422A (en) 1987-06-30 1987-06-30 Key matrix circuit

Publications (1)

Publication Number Publication Date
JPS648422A true JPS648422A (en) 1989-01-12

Family

ID=15789656

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62164257A Pending JPS648422A (en) 1987-06-30 1987-06-30 Key matrix circuit

Country Status (1)

Country Link
JP (1) JPS648422A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4997071A (en) * 1987-05-27 1991-03-05 Valeo Automatic control system for a clutch coupling two rotating shafts

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5592928A (en) * 1979-01-08 1980-07-14 Sanyo Electric Co Ltd Keyboard unit

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5592928A (en) * 1979-01-08 1980-07-14 Sanyo Electric Co Ltd Keyboard unit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4997071A (en) * 1987-05-27 1991-03-05 Valeo Automatic control system for a clutch coupling two rotating shafts

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