JPS5935226A - Keyboard input circuit - Google Patents

Keyboard input circuit

Info

Publication number
JPS5935226A
JPS5935226A JP57144466A JP14446682A JPS5935226A JP S5935226 A JPS5935226 A JP S5935226A JP 57144466 A JP57144466 A JP 57144466A JP 14446682 A JP14446682 A JP 14446682A JP S5935226 A JPS5935226 A JP S5935226A
Authority
JP
Japan
Prior art keywords
vr
resistance
groups
xii
key
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
JP57144466A
Inventor
Munehiro Minami
Original Assignee
Toshiba 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 Toshiba Corp filed Critical Toshiba Corp
Priority to JP57144466A priority Critical patent/JPS5935226A/en
Publication of JPS5935226A publication Critical patent/JPS5935226A/en
Application status is Pending legal-status Critical

Links

Classifications

    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03MCODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M11/00Coding in connection with keyboards or like devices, i.e. coding of the position of operated keys
    • H03M11/22Static coding
    • H03M11/24Static coding using analogue means, e.g. by coding the states of multiple switches into a single multi-level analogue signal or by indicating the type of a device using the voltage level at a specific tap of a resistive divider
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2239/00Miscellaneous
    • H01H2239/01Miscellaneous combined with other elements on the same substrate
    • H01H2239/012Decoding impedances

Abstract

PURPOSE:To detect a key selecting point by a simple circuit even when the number of key selection points is large, by connecting resistance groups to longitudinal and lateral conductor lines of a key matrix, and utilizing voltage drops across the resistance the resistance groups due to key operation. CONSTITUTION:The longitudinal and lateral conductors LC1-LCn of the keyboard matrix 20 are connected to the resistor groups VR1, R0-Rn-1, and VR2, and VR'1, R'0-R'n-1, and VR'2, and those resistance groups are connected to a constant voltage +5V and the ground through changeover switches 21 and 22, respectively. When a desired intersection Xii in the matrix 20 is depressed, a divided voltage in the resistance corresponding to the point Xii is A/D-converted 24 through some resistance groups VR'1-VR'2 and the side of the contact (b) of a relay 23 and then supplied to a CPU through an input interface IF25. Then, relays 21-23 are changed over by a relay driving circuit 27 and a divided voltage in the VR'1-VR'2 is A/D-converted 24 through some of the VR1-VR2 and the contact (m) of the relay 23 and inputted to the CPU through the IF25. The CPU discriminates the position of the Xii by those two voltages.
JP57144466A 1982-08-20 1982-08-20 Keyboard input circuit Pending JPS5935226A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP57144466A JPS5935226A (en) 1982-08-20 1982-08-20 Keyboard input circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP57144466A JPS5935226A (en) 1982-08-20 1982-08-20 Keyboard input circuit

Publications (1)

Publication Number Publication Date
JPS5935226A true JPS5935226A (en) 1984-02-25

Family

ID=15362927

Family Applications (1)

Application Number Title Priority Date Filing Date
JP57144466A Pending JPS5935226A (en) 1982-08-20 1982-08-20 Keyboard input circuit

Country Status (1)

Country Link
JP (1) JPS5935226A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5995642A (en) * 1982-10-27 1984-06-01 Poriteru Corp Multikey type keyboard for inputting data into computer
US5057836A (en) * 1988-01-22 1991-10-15 Kabushiki Kaisha Toshiba Data input apparatus having a microcomputer

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5995642A (en) * 1982-10-27 1984-06-01 Poriteru Corp Multikey type keyboard for inputting data into computer
US5057836A (en) * 1988-01-22 1991-10-15 Kabushiki Kaisha Toshiba Data input apparatus having a microcomputer

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