R×5C348A/B
An increase of two clock pulses once per 20 seconds causes a time count loss of approximately 3ppm (2 / (32768 ×
20 = 3.051ppm). Conversely, a decrease of two clock pulses once per 20 seconds causes a time count gain of 3ppm.
Consequently, deviations in time counts can be corrected with a precision of 1.5ppm. Note that the oscillation
adjustment circuit is configured to correct deviations in time counts and not the oscillation frequency of the 32.768-
kHz clock pulses. For further details, see “USAGES, 2.4 Oscillation Adjustment Circuit”.
2.7 Alarm_W Registers (at Addresses 8h to Ah)
2.7-1 Alarm_W Minute Register (at Address 8h)
D7
—
0
D6
D5
D4
D3
WM8
D2
WM4
D1
WM2
D0
WM40
WM40
Indefinite
WM20
WM20
Indefinite
WM10
WM10
Indefinite
WM1
(For writing)
WM8
WM4
WM2
WM1
(For reading)
Default settings*
0
Indefinite
Indefinite
Indefinite
Indefinite
2.7-2 Alarm_W Hour Register (at Address 9h)
D7
—
0
D6
—
0
D5
D4
D3
WH8
D2
WH4
D1
WH2
D0
WH1
WH20,WP/A
WH20,WP/A
Indefinite
WH10
WH10
Indefinite
(For writing)
WH8
WH4
WH2
WH1
(For reading)
Default settings*
0
0
Indefinite
Indefinite
Indefinite
Indefinite
2.7-3 Alarm_W Day-of-week Register (at Address Ah)
D7
—
0
D6
D5
D4
D3
WW3
D2
WW2
D1
WW1
D0
WW6
WW5
WW4
WW0
(For writing)
WW6
WW5
WW4
WW3
WW2
WW1
WW0
(For reading)
Default settings*
0
Indefinite
Indefinite
Indefinite
Indefinite
Indefinite
Indefinite
Indefinite
)
Default settings: Default value means read/written values when the XSTP bit is set to “1” due to power-on from 0 volts or supply voltage drop.
*
· The D5 bit of the Alarm_W hour register represents WP/A when the 12-hour mode is selected (0 for a.m. and 1
for p.m.). and WH20 when the 24-hour mode is selected (tens in the hour digits).
· The Alarm_W registers should not have any non-existent alarm time settings. (Note that any mismatch between
current time and preset alarm time specified by the Alarm_W registers may disable the alarm circuit.)
· When the 12-hour mode is selected, the hour digits read 12 and 32 for 0 a.m. and 0 p.m., respectively (see “2.1-2
12/24: 12-/24-hour Mode Selection Bit”).
· WW0 to WW6 correspond to W4, W2, and W1 of the day-of-week counter with settings ranging from (0, 0, 0) to (1,
1, 0).
· WW0 to WW6 with respective settings of 0 disable the outputs of the Alarm_W registers.
20
RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
