Real time clock (RTC) having several highly desirable timekeeping dependability and security attributes, and methods for accessing a register thereof
US6772361B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 10, 2000 |
| Grant date | Aug 3, 2004 |
| Priority date | — |
| Expiry date | Jun 17, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2221/2145
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A real time clock (RTC) is described several timekeeping dependability and timekeeping security attributes. The RTC may have several registers for storing values, at least one of which stores a value which is safeguarded. For example, a “TrustQualityState” register stores a “TrustQualityState” value which is dependent upon a timekeeping accuracy of the RTC. The “TrustQualityState” value may also be dependent upon timekeeping stability, reliability, and/or security of the RTC (e.g., a tamper resistance of the RTC). The RTC includes an access unit coupled between the “TrustQualityState” register and a bus used to access the “TrustQualityState” register. The access unit controls access to the “TrustQualityState” register in order to safeguard the “TrustQualityState” value. The access unit receives read and write commands directed to “TrustQualityState” register via the bus. The access unit determines if a source of a received read or write command directed to the register is authorized to access the register, and provides access to the register only if the source is authorized to access the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.