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:
Sep. 09, 1980
Filed:
Feb. 24, 1978
Richard A Magerl, Schaumburg, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
Keyboard input circuitry for use in a microcomputer continuously scans a keyboard having a plurality of keys organized into K columns and J rows. A counter under control of a reset signal and clock signal, sequentially provides K output signals for enabling the K column conductors. When a key in the Kth column and Jth row is depressed, the Kth output signal from the counter will be coupled to the Jth row. Thus, the logical state of the J row conductors will determine whether or not a key of the enabled column of keys is depressed or not. The microcomputer includes a register, a memory, and a peripheral interface adapter circuit. The microcomputer provides the reset signal and clock signal to the register and to the counter by way of the peripheral interface adapter circuit, for maintaining synchronism between the register and counter. For each enabled column of keys, the microcomputer senses the logical states of the J row conductors via the peripheral interface adapter circuit, and then ascertains whether or not a particular key is depressed by the sensed logical state of its row conductor and the state of the register.