S-35399A03 Datasheet, PDF (19/51 Pages) Seiko Instruments Inc – 2-WIRE REAL-TIME CLOCK

Rev.1.0_00
2-WIRE REAL-TIME CLOCK
S-35399A03
„ Power-on Detector and Register Status
The power-on detection circuit operates by power-on the S-35399A03, as a result each register is cleared; each register is
set as follows.
Real-time data register :
Status register 1 :
Status register 2 :
INT1 register :
INT2 register :
Clock correction register :
Free register 1 :
Free register 2 :
Free register 3 :
Up counter :
Alarm expansion register 1 :
Alarm expansion register 2 :
00 (Y), 01 (M), 01 (D), 0 (day of the week), 00 (H), 00 (M), 00 (S)
“01h”
“01h”
“80h”
“00h”
“00h”
“00h”
“00h”
“00h”
“00 00 00h”
“00h”
“00h”
“1” is set in the POC flag (B0 in the status register 1) to indicate that power has been applied. To correct the oscillation
frequency, the status register 2 goes in the mode the output of user-set frequency, so that 1 Hz clock pulse is output from
the INT1 pin. When “1” is set in the POC flag, be sure to initialize. The POC flag is set to “0” due to initialization so that the
output of user-set frequency mode is cleared. (Refer to “„ Register Status After Initialization”.)
For the regular operation of power-on detection circuit, the period to power-up the S-35399A03 is that the voltage reaches
1.3 V within 10 ms after setting the IC’s power supply voltage at 0 V. When the power-on detection circuit is not working
normally is; the POC flag (B0 in the status register) is not in “1”, or 1 Hz is not output from the INT1 pin. In this case,
power-on the S-35399A03 once again because the internal data may be in the indefinite status.
Do not transmit data immediately after power-on at least one sec because the power-on detection circuit is operating.
Within 10 ms
1.3 V
0 V^*1
*1. 0 V indicates that there are no potential differences between the VDD
pin and VSS pin of the S-35399A03.
Figure 20 How to raise the power supply voltage
Seiko Instruments Inc.
19