R2025S/D
• Calendar Counter (Address 4-6h)
Day-of-month Counter (Address 4h)
D7
D6
D5
D20
D4
D10
D3
D8
D2
D4
D1
D2
D0
D1
-
-
(For Writing)
0
0
0
0
D20
Indefinite
D10
Indefinite
D8
Indefinite
D4
Indefinite
D2
Indefinite
D1
Indefinite
(For Reading)
Default Settings *)
Month Counter + Century Bit (Address 5h)
D7
D6
D5
D4
D3
D2
D1
D0
-
-
MO10
MO8
MO4
MO2
MO1
(For Writing)
/19⋅20
0
0
0
0
MO10
Indefinite
MO8
Indefinite
MO4
Indefinite
MO2
Indefinite
MO1
Indefinite
(For Reading)
Default Settings *)
/19⋅20
Indefinite
Year Counter (Address 6h)
D7
D6
D5
D4
D3
D2
D1
D0
Y80
Y40
Y20
Y10
Y8
Y4
Y2
Y1
(For Writing)
Y80
Indefinite
Y40
Indefinite
Y20
Indefinite
Y10
Indefinite
Y8
Indefinite
Y4
Indefinite
Y2
Indefinite
Y1
Indefinite
(For Reading)
Default Settings *)
*) Default settings: Default value means read / written values when the PON bit is set to “1” due to VDD
power-on from 0 volts.
* The calendar counters are configured to display the calendar digits in BCD format by using the automatic
calendar function as follows:
The day-of-month digits (D20 to D1) range from 1 to 31 for January, March, May, July, August, October, and
December; from 1 to 30 for April, June, September, and November; from 1 to 29 for February in leap years;
from 1 to 28 for February in ordinary years. The day-of-month digits are carried to the month digits in
reversion from the last day of the month to 1. The month digits (MO10 to MO1) range from 1 to 12 and are
carried to the year digits in reversion from 12 to 1.
The year digits (Y80 to Y1) range from 00 to 99 (00, 04, 08, …, 92, and 96 in leap years) and are carried to
the /19⋅20 digits in reversion from 99 to 00.
The /19⋅20 digits cycle between 0 and 1 in reversion from 99 to 00 in the year digits.
* Any carry from lower digits with the writing of non-existent calendar data may cause the calendar counters
to malfunction. Therefore, such incorrect writing should be replaced with the writing of existent calendar
data.
• Oscillation Adjustment Register (Address 7h)
D7
(0)
D6
F6
D5
F5
D4
F4
D3
F3
D2
F2
D1
F1
D0
F0
(For Writing)
0
0
F6
0
F5
0
F4
0
F3
0
F2
0
F1
0
F0
0
(For Reading)
Default Settings *)
*) Default settings: Default value means read / written values when the PON bit is set to “1” due to VDD
power-on from 0 volts.
(0) bit:
(0) bit should be set to 0
F6 to F0 bits:
* The Oscillation Adjustment Circuit is configured to change time counts of 1 second on the basis of the
settings of the Oscillation Adjustment Register when the second digits read 00, 20, or 40 seconds. Normally,
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RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
