DS1337 Datasheet, PDF (5/13 Pages) Dallas Semiconductor – Serial Real-Time Clock

DS1337
PIN DESCRIPTION
PIN
NAME
DESCRIPTION
These signals are connections for a standard 32.768kHz quartz crystal. The internal
1
X1
oscillator circuitry is designed for operation with a crystal having a specified load
capacitance (C_L) of 6pF. For more information about crystal selection and crystal layout
considerations, refer to Application Note 58: Crystal Considerations with Dallas Real-
Time Clocks. An external 32.768kHz oscillator can also drive the DS1337. In this
2
X2
configuration, the X1 pin is connected to the external oscillator signal and the X2 pin is
floated.
Interrupt Output. When enabled, INTA is asserted low when the time/day/date matches
3
INTA
the values set in the alarm registers. This pin is an open-drain output and requires an
external pullup resistor.
4
GND
DC power is provided to the device on these pins.
5
SDA
Serial Data Input/Output. SDA is the input/output pin for the 2-wire serial interface. The
SDA pin is open-drain output and requires an external pullup resistor.
6
SCL
Serial Clock Input. SCL is used to synchronize data movement on the serial interface.
7
SQW/INTB
Square-Wave/Interrupt Output. Programmable square-wave or interrupt output signal. It
is an open-drain output and requires an external pullup resistor.
8
VCC
DC power is provided to the device on these pins.
Figure 1. Recommended Layout for Crystal
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