Horology: time measuring systems or devices – Electrical time base
Reexamination Certificate
1997-01-28
2001-06-19
Miska, Vit (Department: 2859)
Horology: time measuring systems or devices
Electrical time base
C702S178000
Reexamination Certificate
active
06249488
ABSTRACT:
TECHNICAL FIELD
The present application pertains to timekeeping circuits and, more particularly, to low power timekeeping circuits.
BACKGROUND OF THE INVENTION
Most computers include a timekeeping module or system which keeps track of the present time of day and date using its own oscillator. These timekeeping systems receive their primary power from the computer system but have backup batteries in order to preserve the time data when the primary power source fails. Since the useful life of the backup battery depends generally on the amount current drawn by the timekeeping system, the power supply current used by the timekeeping system generally determines how often battery replacement is required. Therefore it can be appreciated that a timekeeping system which operates with a relatively small amount of power supply current is highly desirable.
SUMMARY OF THE INVENTION
It is, therefore, an object of this invention to provide a timekeeping system which requires a relatively small amount of power supply current.
Shown in an illustrated embodiment of the invention is a method for keeping time which includes reading seconds data from a memory, incrementing the seconds data, and storing the incremented seconds data back into the memory. If the seconds data, before being incremented, was 59 seconds, then the minutes data is read, incremented, and the incremented minutes data is stored in the memory. If the minutes data, prior to being incremented, was at
59
minutes, then the hours data is read from the memory, incremented, and the incremented hours data is stored back into the memory.
Also shown in an illustrated embodiment of the invention is a method for keeping time in a timekeeping system which includes a sequencer, a memory, and an accumulator connected together by a data bus which includes placing the seconds data onto the data bus by the memory and reading the seconds data in the accumulator. The accumulator increments the seconds data and writes the incremented seconds data onto the data bus. The incremented seconds data is stored in the memory and the memory holds the incremented seconds data on the data bus until at least a next read operation by the memory or a next write operation by the accumulator.
REFERENCES:
patent: 4001569 (1977-01-01), Dickinson et al.
patent: 4218876 (1980-08-01), Hashimoto et al.
patent: 4240150 (1980-12-01), Ebihara et al.
patent: 4250571 (1981-02-01), Ebihara et al.
patent: 4267587 (1981-05-01), Mizuno et al.
patent: 4330840 (1982-05-01), Kobayashi
patent: 4367051 (1983-01-01), Inoue
patent: 4873665 (1989-10-01), Jiang et al.
patent: 4970669 (1990-11-01), McIntosh et al.
patent: 5022006 (1991-06-01), Fifield et al.
Podkowa William J.
Williams Clark R.
Dallas Semiconductor Corporation
Jenkens & Gilchrist a Professional Corporation
Miska Vit
LandOfFree
System and method for keeping time does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method for keeping time, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for keeping time will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2520651