RS5C348A RICOH Co.,Ltd., RS5C348A Datasheet - Page 42

• Manufacturer Part Number: RS5C348A
• Description: 4-wire Serial Interface Real-time Clock
• Manufacturer: RICOH Co.,Ltd.

Rx5C348A/B
Rev.2.01
Typical Software-based Operations
Initialization at Power-on
Writing of Time and Calendar Data
12345
*1)
*2)
*3)
*4)
Set Oscillation Adjustment
Write to Time Counter and
Register 1 and 2, etc.
Register and Control
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.
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
This step is not required when the supply voltage monitoring circuit is not used.
This step involves ordinary initialization including the Oscillation Adjustment Register and interrupt
cycle settings, etc.
Calendar Counter
Power-on
XSTP=1?
CE ← H
CE ← L
Start
Yes
*1)
*4)
*2)
*1)
*2)
*3)
No
*1) When writing to clock and calendar counters, do not drive CE to “L” until
*2) Any writing to the second counter will reset divider units lower than the
*3) Take care so that process from CE driving to “H” to driving to “L” will be
all times from second to year have been written to prevent error in writing
time. (Detailed in "P.24
Time Data under special condition
second digits.
complete within 1.0sec. (Detailed in "P.24
frequency
The Rx5C348A/B may also be initialized not at power-on but in the
process of writing time and calendar data.
VDET=0?
Yes
*3)
XSTP and VDET".
".
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Battery Run-down
Warning Back-up
No
Considerations in Reading and Writing
".
Adjustment of Oscillation