RX5C348A Datasheet, PDF (42/45 Pages) RICOH electronics devices division – 4-WIRE SERIAL INTERFACE

Rx5C348A/B
Typical Software-based Operations
Initialization at Power-on
Start
*1)
Power-on
*2)
XSTP=1?
No
Yes _*4)
Set Oscillation Adjustment
Register and Control
Register 1 and 2, etc.
*3)
VDET=0?
Yes
No
Warning Back-up
Battery Run-down
*1) After power-on from 0 volt, the start of oscillation and the process of internal initialization require a
time span on 1to 2seconds, so that access should be done after the lapse of this time span or more.
*2) The XSTP bit setting of 0 in the Control Register 1 indicates power-on from backup battery and not
from 0v. For further details, see "P.32 XSTP and VDET".
*3) This step is not required when the supply voltage monitoring circuit is not used.
*4) This step involves ordinary initialization including the Oscillation Adjustment Register and interrupt
cycle settings, etc.
Writing of Time and Calendar Data
*1)
CE ← H
*2)
Write to Time Counter and
Calendar Counter
CE ← L
*3)
*1) When writing to clock and calendar counters, do not drive CE to “L” until
all times from second to year have been written to prevent error in writing
time. (Detailed in "P.24 Considerations in Reading and Writing
Time Data under special condition ".
*2) Any writing to the second counter will reset divider units lower than the
second digits.
*3) Take care so that process from CE driving to “H” to driving to “L” will be
complete within 1.0sec. (Detailed in "P.24 Adjustment of Oscillation
frequency".
The Rx5C348A/B may also be initialized not at power-on but in the
process of writing time and calendar data.
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Rev.2.01
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