AN1759 Datasheet, PDF (1/24 Pages) Freescale Semiconductor, Inc – Add a Non-Volatile Clock to the MC68HC705J1A

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AN1759
Add a Non-Volatile Clock to the MC68HC705J1A
By Mark Glenewinkel
Field Applications Engineering
Consumer Systems Group
Austin, Texas
Introduction
Many embedded systems require the measurement of time. This can be
accomplished internally by some MCUs that have on-chip real-time
clocks. Even so, for date, month, and leap year measurement, this task
can take substantial amounts of bandwidth and code space.
The DS1307 64x8 serial real-time clock provides calendar and time
keeping functions along with system-enhancing non-volatile RAM. With
a 2-wire interface, timekeeping can be managed easily.
Some applications of using the DS1307 are:
• Logging of chronological events
• Tracking power down time of a system
• Providing alarm functions
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