AN925 Datasheet, PDF (3/4 Pages) STMicroelectronics – Time Update in ST’s TIMEKEEPER Devices

AN925 - APPLICATION NOTE
An alternative approach, shown in Figure 3, is adopted by the M48T02, M48T12, M48T08, M48T18,
M48T58 (revision C), , M48T59 (revision C), M48T37 and M48T201 devices. The spacing between suc-
cessive System-to-User-Update-Pulse is always one second. Each pulse is delayed by the same delta
time, of 3.5 ms, regardless of the number of registers that need incrementing within that period.
Figure 3. Time Update Waveform Diagram (fixed delay)
1 Hz clock frequency
Seconds register update
Minutes register update
Hours register update
Day of week register update
Date register update
Month register update
Year register update
Reference update pulse
System to user update pulse
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= 1 second
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AI02484
(These examples are each shown with the calibration set to zero.)
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