DS1307_06 Datasheet, PDF (9/15 Pages) Maxim Integrated Products – 64 x 8, Serial, I2C Real-Time Clock

DS1307 64 x 8, Serial, I²C Real-Time Clock
CONTROL REGISTER
The DS1307 control register is used to control the operation of the SQW/OUT pin.
BIT 7
OUT
BIT 6
0
BIT 5
0
BIT 4
SQWE
BIT 3
0
BIT 2
0
BIT 1
RS1
BIT 0
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
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