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:
Oct. 17, 2006
Filed:
Aug. 26, 2003
Alin Theodor Iacob, Sunnyvale, CA (US);
Alin Theodor Iacob, Sunnyvale, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A system and method for scanning a data-input array (e.g., a keyboard or keypad) using a reduced number of signals is disclosed. Specifically, a switch array is disclosed comprising a plurality of switches and a plurality of input/output (I/O) lines. The switch array is arranged in an N*N matrix. A plurality of N I/O lines is used to scan the matrix. In one embodiment, the switches in the array are arranged in an N*(N−1)/2 configuration. In this configuration, there is no duplication of circuit paths. In another embodiment, the switches in the array are arranged in an N(N−1) configuration. In this configuration, a plurality of diodes are used to identify an activated switch depending upon which of a plurality of signal paths is activated. The plurality of diodes is included to differentiate between pairs of switches that complete the same paths between pairs of I/O lines.