S-35399A03 Datasheet, PDF (31/51 Pages) Seiko Instruments Inc – 2-WIRE REAL-TIME CLOCK

Rev.1.0_00
2-WIRE REAL-TIME CLOCK
S-35399A03
„ Up-Count Operation
The up counter is a 24-bit read-only binary counter. This counter starts counting from “000000h” from power-on and returns
to “000000h” at the next clock after it has reached “FFFFFFh”. A clock pulse is a pulse that is output when the second-data
in the real-time data is “00h”. Therefore, some delay is made in the period that a clock pulse is being output due to Write
timing and Write data. The registers are not initialized unless power-on again, so that users are able to grasp the elapsed
time from power-on up to 30 years. Figure 32 shows the example of timing chart of up counter’s operation.
Power supply
Clock pulse
of real-time
second data
"00h"
OFF
ON
Write real-time
second data:
20 seconds
40 s 40 s
Write real-time
second data:
50 seconds
60 s 20 s 10 s
24-bit binary
up counter
000000 h 000001 h 000010 h
OFF
60 s
60 s
FFFFFF h 000000 h 000001 h
A clock pulse is
60 seconds or more.
A clock pulse is
60 seconds or less.
Figure 32 Timing Chart of 24-Bit Binary Up Counter
Seiko Instruments Inc.
31