Keypad
US7133029B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 2001 |
| Grant date | Nov 7, 2006 |
| Priority date | — |
| Expiry date | Mar 7, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2239/032
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A keypad is disclosed which has a plurality of keys (12) for the input of information. Each key has a first switch (80) and a second switch (90). The first switches (80) are all connected to a common electrical interconnection (120) and the second switches (90) are connected into a matrix electrical interconnection (62, 100). The microprocessor (66) detects a global signal on the common interconnection (120) and supplies scan signals to the matrix interconnection (62, 100) to enable detection of a particular key. The processor (66) may also selectively change the state of lines (62, 100) of the matrix and also maintain particular lines in a predetermined state by open drain ports of the processor to which the lines of the matrix are connected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.