S-35392A Datasheet, PDF (17/47 Pages) Seiko Instruments Inc – 2-WIRE REAL-TIME CLOCK

Rev.1.3_00
2-WIRE REAL-TIME CLOCK
S-35392A
„ Power-on Detector and Register Status
The power-on detection circuit operates by power-on the S-35392A, 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 :
00 (Y), 01 (M), 01 (D), 0 (day of the week), 00 (H), 00 (M), 00 (S)
“01h”
“01h”
“80h”
“00h”
“00h”
“00h”
“1” is set in the POC flag (B0 in the status register 1) to indicate that power has been applied. In this case, be sure to
initialize. The POC flag is set to “0” due to initialization. (Refer to “„ Register Status After Initialization”.)
For the regular operation of power-on detection circuit, as seen in Figure 18, the period to power-up the S-35392A is that
the voltage reaches 1.3 V within 10 ms after setting the IC’s power supply voltage at 0 V. When the POC flag (B0 in the
status register) is not in “1”, in this case, power-on the S-35392A once again.
Do not transmit data immediately after power-on at least 0.5 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-35392A.
Figure 18 How to Raise the Power Supply Voltage
Seiko Instruments Inc.
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