DS1307 64 x 8, Serial, I

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CONTROL REGISTER

The DS1307 control register is used to control the operation of the SQW/OUT pin.

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

BIT 0

OUT

0

0

SQWE

0

0

RS1

RS0

Bit 7: Output Control (OUT). This bit controls the output level of the SQW/OUT pin when the square-

wave output is disabled. If SQWE = 0, the logic level on the SQW/OUT pin is 1 if OUT = 1 and is 0 if

OUT = 0.

Bit 4: Square-Wave Enable (SQWE). This bit, when set to logic 1, enables the oscillator output. The

frequency of the square-wave output depends upon the value of the RS0 and RS1 bits. With the square-

wave output set to 1Hz, the clock registers update on the falling edge of the square wave.

Bits 1, 0: Rate Select (RS1, RS0). These bits control the frequency of the square-wave output when the

square-wave output has been enabled. The following table lists the square-wave frequencies that can be

selected with the RS bits.

RS1

RS0

SQW/OUT OUTPUT

SQWE

OUT

0

0

1Hz

1

X

0

1

4.096kHz

1

X

1

0

8.192kHz

1

X

1

1

32.768kHz

1

X

X

X

0

0

0

X

X

1

0

1