Key input apparatus using a switching matrix

Abstract

The present invention relates to a key input apparatus using a switching matrix, the apparatus comprising: a column scan control unit, which includes switches showing one-to-one correspondence with lines in a column scan direction in response to a column scan signal and an enable signal (EN) from a main controller, the switches receiving one input voltage selected out of two input voltages (Vup, VA) per column in a normal scan mode and receiving a standby voltage (Vh) in a power saving mode, thereby executing a column scan operation according to the modes; and a row scan control unit, which executes, in the normal scan mode, a row scan operation in response to a row scan signal from the main controller, with the row scan signal being given synchronously with a column scan signal for the column scan control unit and which operates in the power saving mode in response to the enable signal (EN). Accordingly, with a key input apparatus of the present invention utilizing switches of simple configuration to control the switching matrix, there can be no ghost key, the key input apparatus can be operated in the power saving mode and costs of manufacturing can be cut down.

Description

technical field [0001] The present invention relates to an input operation detecting device for detecting switch operation in a switch matrix having a plurality of switches such as a keyboard. Background technique [0002] Generally speaking, in a computer system, the keyboard is the main device for receiving input from the outside. [0003] In many computer systems, data input to the central processing system is accomplished by keystrokes. [0004] A keyboard interface including a control unit for controlling key input information is usually installed on the keyboard, and a scan output line (Scan out line) output from a microcomputer (micom) and a scan input line (Scan out line) input to the microcomputer are connected to the keyboard interface. Scan in line). [0005] The system interface transmits a status signal to the keyboard interface through the scan input line, and connects the scan output line and the scan input line according to the key input to judge the key in...

AI Technical Summary

Problems solved by technology

[0047] However, the above-mentioned existing method for eliminating the Ghost Key phenomenon needs to separately form a decoder and a selector in the arrangement of the switch matrix, thereby increasing the system area, increasing the production cost of the product, and increasing the design difficulty

In addition, because there is no definition of power-saving state, it will affect commercialization

[0048] In addition, because the number of ordinary diodes (Di) equivalent to the second group of lines (30-36) and Zener diodes (ZDi) for providing a constant voltage are required in the switch arrangement, the manufacturing cost is increased and the manufacturing difficulty is increased.

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