The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 28, 1996
Filed:
May. 01, 1992
Bok H Pack, Kyungki-do, KR;
Gold Star Co., Ltd., Seoul, KR;
Abstract
A key signal input circuit for a microcomputer including a microprocessor and a single input port. The microcomputer outputs, in sequence at a constant interval, a plurality of grid signals, receives different key signal inputs successively through the single input port synchronously with the grid signals, and discriminates the inputted key signals to recognize which keys have been selected. The key signal input circuit includes a power supply circuit, responsive to the grid signals from the microcomputer, having a plurality of power supply lines for supplying, in sequence at a constant interval, a desired power through the power supply lines. A key matrix circuit having a plurality of sets of keys, responsive to the desired power through the power supply lines from the power supply circuit and to on/off states of the keys, coupled, by sets, respectively to the power supply lines. The key matrix circuit applies the key signals successively to the microcomputer.