Keypad de-bouncing apparatus and method
US8407381B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 13, 2010 |
| Grant date | Mar 26, 2013 |
| Priority date | — |
| Expiry date | Mar 12, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2201/002
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for de-bouncing keypad inputs is disclosed including interrupting a processor upon detecting a key press, reading input signals from the key pad to determine an initial port value and starting a timer. A keypad interrupt is disabled and processing resumes until expiration of the timer. The timer interrupts the processor and the input signals are read a second time and combined with the initial port value to determine a key identifier. The timer is started again and processing resumes. Upon expiration of the timer the processor checks for key release. If release is not detected, the timer is again started. If release occurs, the timer is disabled and the keypad interrupt is enabled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.