RV5C339A_03 Datasheet, PDF (35/46 Pages) RICOH electronics devices division – 3-WIRE SERIAL INTERFACE REAL-TIME CLOCK IC WITH VOLTAGE MONITORING FUNCTION

RV5C339A
4.1 Alarm Interrupt
The alarm circuit is controlled by the enable bits (i.e. the WALE and DALE bits in the control register 1) and the
flag bits (i.e. the WAFG and DAFG bits in the control register 2). The enable bits can be used to enable this circuit
when set to 1 and to disable it when set to 0. When intended for reading, the flag bits can be used to monitor alarm
interrupt signals. When intended for writing, the flag bits will cause no event when set to 1 and will drive high (dis-
able) the alarm circuit when set to 0.
The enable bits will not be affected even when the flag bits are set to 0. In this event, therefore, the alarm circuit will
continue to function until it is driven low (enabled) upon the next occurrence of a match between current time and
preset alarm time.
The alarm function can be set by presetting desired alarm time in the alarm registers (the Alarm_W registers for the
day-of-week digit settings and both the Alarm_W registers and the Alarm_D registers for the hour and minute digit
settings) with the WALE and DALE bits once set to 0 and then to 1 in the control register 1. Note that the WALE
and DALE bits should be once set to 0 in order to disable the alarm circuit upon the coincidental occurrence of a
match between current time and preset alarm time in the process of setting the alarm function.
INTRB (INTRA) pin
Interval (1 minute) during which
a match between current time
and preset alarm time occurs
MAX.61.1µs
INTRB (INTRA) pin
Setting WALE
and DALE
bit to 1
Match between
current time and
preset alarm time
in the day-of-week
and hour settings
Setting WALE Setting WALE
and DALE and DALE
bit to 0
bit to 1
Setting WALE ^{Match between}
and DALE
bit to 0
current time and
preset alarm time
in the day-of-week
and hour settings
Setting WALE
and DALE
bit to 1
Match between
current time and
preset alarm time
in the day-of-week
and hour settings
Setting WAFG
and DAFG
bit to 0
Match between
current time and
preset alarm time
in the day-of-week
and hour settings
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