RS5C348A RICOH Co.,Ltd., RS5C348A Datasheet - Page 13

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

Rev.2.01
(4) TEST
(5) CT2, CT1, and CT0
The TEST bit is used only for testing in the factory and should normally be set to 0.
* 1) Pulse Mode: 2-Hz and 1-Hz clock pulses are output in synchronization with the increment of the
* 2) Level Mode: Periodic interrupt signals are output with selectable interrupt cycle settings of 1 second, 1
TEST
CT2
0
0
0
0
1
1
1
1
0
1
second counter as illustrated in the timing chart below.
In the pulse mode, the increment of the second counter is delayed by approximately 92 µs from the
falling edge of clock pulses. Consequently, time readings immediately after the falling edge of clock
pulses may appear to lag behind the time counts of the real-time clocks by approximately 1 second.
Rewriting the second counter will reset the other time counters of less than 1 second, driving the
/INTR pin low.
minute, 1 hour, and 1 month. The increment of the second counter is synchronized with the falling
edge of periodic interrupt signals. For example, periodic interrupt signals with an interrupt cycle
setting of 1 second are output in synchronization with the increment of the second counter as
illustrated in the timing chart below.
CTFG Bit
/INTR Pin
CT1
0
0
1
1
0
0
1
1
Description
CT0
0
1
0
1
0
1
0
1
Test Bit
Periodic Interrupt Selection Bits
Normal operation mode.
Test mode.
(Increment of second counter)
Description
Wave
mode
Approx. 92µs
-
-
Pulse Mode
*1)
Pulse Mode
*1)
Level Mode
*2)
Level Mode
*2)
Level Mode
*2)
Level Mode
*2)
form
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)
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Rewriting of the second counter
12345
Rx5C348A/B
(Default)
(Default)