Method and apparatus for scanning keyboard and diode option
US5856794A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 6, 1997 |
| Grant date | Jan 5, 1999 |
| Priority date | — |
| Expiry date | Jun 6, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M11/20
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for improved scanning keyboard and diodes option is disclosed. Each of the pins is treated as one independent dimension so as to define a multi-dimensional configuration. The circuit includes a clock generation circuit, a keyboard I/O port device comprising a plurality of ports associated with the pins and a key detection register device. A key is arranged at the interconnection of any two ports. When the key is depressed, by maintaining the ports at a first level and applying a second level to each of the ports to check which port goes from the first level to the second level, the location of the key may be determined. The output of the ports are stored in the key detection register device for the determination of the key location.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.