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2015-12-0001

PT0280-8

12/11/15

15

PT7C43390/43390C

Real-time Clock Module

For the regular operation of power-on detection circuit, as seen in below Figure, the period to power-up the RTC 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 INT pin.

In this case, power-on the RTC once again because the internal data may be in the indefinite status.

Moreover, regarding the processing right after power-on, refer to "Flowchart of Initialization and Example of Real-time Data

Set-up".

*1. 0 V indicates that there are no potential differences between the VDD pin and VSS pin.

How to Raise the Power Supply Voltage

5. Register Status After Initialization

The status of each register after initialization is as follows.

Real-time data register: 00 (Y), 01 (M), 01 (D), 0 (day of the week), 00 (H), 00 (M), 00 (S)

Status register 1: "0 B6 B5 B4 0 0 0 0 b"

(In B6, B5, B4, the data of B6, B5, B6 in the status register 1 at initialization is set. Refer to below Figure.)

Status register 2: "00h"

INT1 register: "00h"

INT2 register: "00h"

Clock correction register: "00h"

Free register: "00h"

 Status Register 1 Data at Initialization