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The RTC module breakout provides all the components needed for timing, communication and maintaining power.
The communication and power pins are all broken down into a 5-pin header with pin labels located on the top of the boardIts bottom consists almost entirely of a 12mm coin cell battery holder
The five pin breakouts on the board provide access to the communication interface and allow you to supply the chip's primary power source
SDA——I²C bus data line
SCL——I²C bus clock line
SQW——Configurable square-wave output
GND——Ground (0V) supply
5V—DS1307 VCC power supply input
You need is four wires between your microcontroller and the breakout board: power, ground, data, and clock. The SQW pin can optionally be wired to the Arduino and used as a pulse-counter.Below is a sample connection diagram demonstrating how to connect the development board to other boards:
