Method and apparatus for increasing the number of keys of a key-matrix
US6417787B1 · kind B1 · utility
7Cited by
5References
9Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 24, 1999 |
| Grant date | Jul 9, 2002 |
| Priority date | — |
| Expiry date | Aug 24, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M11/20
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An apparatus and a method for increasing the number of keys in a ready made key-matrix , it is necessary to increase some extra diodes and change the keyboard scanning method . To increase some extra keys in the key-matrix, the diodes are in series with the keys, and the keyboard scanning method is executed by detecting the conductive direction of the diodes. The method avoids redesigning any IC to increase I/O ports, therefore, it can save the cost of redesigning and advance the sale.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.