R2025S/D
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 (disable) the alarm interrupt 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
interrupt 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 interrupt circuit upon the coincidental
occurrence of a match between current time and preset alarm time in the process of setting the alarm function.
Interval (1min.) during which a match
between current time and preset alarm time
occurs
/INTRB
(/INTRA)
current time =
current time =
WALE←1
WALE←1
WALE←0
preset alarm time
preset alarm time
(DALE)
(DALE)
(DALE)
/INTRB
(/INTRA)
current time =
preset alarm time
current time =
preset alarm time
WALE←1
(DALE)
WAFG←0
(DAFG)
• Periodic Interrupt
Setting of the periodic selection bits (CT2 to CT0) enables periodic interrupt to the CPU. There are two waveform
modes: pulse mode and level mode. In the pulse mode, the output has a waveform duty cycle of around 50%. In
the level mode, the output is cyclically driven low and, when the CTFG bit is set to 0, the output is return to High
(OFF).
CT2
CT1
CT0
Description
Wave form
mode
Interrupt Cycle and Falling Timing
0
0
0
0
1
0
0
1
1
0
0
1
0
1
0
-
-
OFF(H)
Fixed at “L”
2Hz(Duty50%)
1Hz(Duty50%)
Once per 1 second (Synchronized with
Second counter increment)
Once per 1 minute (at 00 seconds of every
Minute)
Once per hour (at 00 minutes and 00
Seconds of every hour)
(Default)
Pulse Mode *1)
Pulse Mode *1)
Level Mode *2)
1
1
1
0
1
1
1
0
1
Level Mode *2)
Level Mode *2)
Level Mode *2)
Once per month (at 00 hours, 00 minutes,
and 00 seconds of first day of every month)
35
RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
