The RTC module is specifically designed for Raspberry Pi. It communicated with Raspberry Pi through I2C bus. There is a Maxim DS1307 and CR1220 button cell on the board to keep the real time for a long time after the Raspberry Pi has it’s power off. In order to offering a convenient way to debug, there are five pin has been setup which are 5v, 3.3v, Rxd,Txd on borad.
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