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2015-12-0001

PT0280-8

12/11/15

11

PT7C43390/43390C

Real-time Clock Module

Minute data (00 to 59): m1, m2, m4, m8, m10, m20, m40

Example: 32 minutes (m1, m2, m4, m8, m10, m20, m40, 0) = (0, 1, 0, 0, 1, 1, 0, 0)

Example: 55 minutes (m1, m2, m4, m8, m10, m20, m40, 0) = (1, 0, 1, 0, 1, 0, 1, 0)

Second data (00 to 59): s1, s2, s4, s8, s10, s20, s40

Example: 19 seconds (s1, s2, s4, s8, s10, s20, s40, 0) = (1, 0, 0, 1, 1, 0, 0, 0)

3.2. Status Register 1

Status register 1 is a 1-byte register that is used to display and set various modes. The bit configuration is shown below.

B1: BLD

This flag is set to "1" when the power supply voltage decreases to the level of detection voltage (VDET) or less. Users can detect a

drop in the power supply voltage. This flag is set to "1" once, is not set to "0" again even if the power supply increases to the level

of detection voltage (VDET) or more. This flag is read-only. When this flag is "1", be sure to initialize. Regarding the operation of

the power supply voltage detection circuit, refer to "Low Power Supply Voltage Detection Circuit".

B2: INT2, B3: INT1

This flag indicates the time set by alarm and when the time has reached it. This flag is set to "1" when the time that users set by

using the alarm interrupt function has come. The INT1 flag at alarm 1 interrupt mode and the INT2 flag at alarm 2 interrupt mode

are set to "1". Set "0" in INT1AE (B5 in the status register 2) or in INT2AE (B1 in the status register 2) after reading "1" in the

INT1 flag or in the INT2 flag. This flag is read-only. This flag is read once, is set to "0" automatically.

B4: SC1, B5: SC0

These flags are SRAM type registers, they are 2 bits as a whole, can be freely set by users.

B6: 12 / 24

This flag is used to set 12-hour or 24-hour mode. Set the flag ahead of write operation of the real-time data register in case of 24-

hour mode.

0: 12-hour mode

1: 24-hour mode

B7: RESET

The internal IC is initialized by setting this bit to "1". This bit is write-only. It is always "0" when reading. When applying the

power supply voltage to the IC, be sure to write "1" to this bit to initialize the circuit. Regarding each status of data after

initialization, refer to "Register Status after Initialization".

3.3. Status Register 2

Status register 2 is a 1-byte register that is used to display and set various modes. The bit configuration is shown below.

INT1FE

INT1ME

INT1AE

32kE

INT2FE

INT2ME

INT2AE

TEST

B7

B6

B5

B4

B3

B2

B1

B0

R/W

R/W

R/W

R/W

R/W

R/W

R/W

R/W

R/W : Read/Write

B0: TEST

This is a test flag. Be sure to set this flag to "0" in use. If this flag is set to "1", be sure to initialize to set "0".

B1: INT2AE, B2: INT2ME, B3: INT2FE

These bits are used to select the output mode for the INT2 pin. Below Table shows how to select the mode. To use an alarm 2

interrupt, set alarm interrupt mode, then access the INT2 register.

Table: Output Modes for INT2 Pin