Apparatus for detecting abnormalitey of clock in microcomputer used for motor vehicle
US5954772A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 1997 |
| Grant date | Sep 21, 1999 |
| Priority date | — |
| Expiry date | May 8, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C7/22
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for detecting the abnormality of a clock in a microcomputer used for a motor vehicle includes a reference clock generator for generating a reference clock signal required for operation of the microcomputer, a pulse signal generator for generating a pulse signal of a constant period based on an instruction signal from the microcomputer, a comparator for comparing the pulse signal from the pulse signal generator and the reference clock signal from the reference clock generator and producing a comparison signal based on the result of comparison, and a determining circuit for determining, based on the comparison signal from the comparator, whether or not the reference clock signal is normal. An indicator is enabled only when the reference clock signal is in the abnormal state. The abnormality of the reference clock can be detected without requiring a separate oscillator used for generating an additional clock signal for comparison with the reference clock signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.