RS5C348A RICOH Co.,Ltd., RS5C348A Datasheet - Page 35

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

Rev.2.01
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 interrupts circuit upon the
coincidental occurrence of a match between current time and preset alarm time in the process of setting the
alarm function.
After setting WALE(DALW) to 0, Alarm registers is set to current time, and WALE(DALE) is set to 1, /INTR will be
not driven to “L” immediately, /INTR will be driven to “L” at next alarm setting time.
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
Periodic Interrupt
0
0
0
0
1
1
1
1
/INTR
/INTR
*1) Pulse Mode:
(DALE)
(DALE)
CT1
WALE←1
WALE←1
0
0
1
1
0
0
1
1
2-Hz and 1-Hz clock pulses are output in synchronization with the increment of the second counter as
illustrated in the timing chart below.
/INTR Pin
CTFG Bit
CT0
0
1
0
1
0
1
0
1
current time =
preset alarm time
current time =
preset alarm time
Interval (1min.) during which a match
between current time and preset alarm time
occurs
Description
Wave form mode
-
-
Pulse Mode *1)
Pulse Mode *1)
Level Mode *2)
Level Mode *2)
Level Mode *2)
Level Mode *2)
(Increment of second counter)
(DALE)
WALE←0
Approx. 92 µ s
(DAFG)
WAFG←0
(DALE)
WALE←1
Interrupt Cycle and Falling Timing
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)
Once per month (at 00 hours, 00 minutes,
and 00 seconds of first day of every month)
- 35 -
Rewriting of the second counter
current time =
preset alarm time
current time =
preset alarm time
12345
Rx5C348A/B
(Default)