Datasheet

RTC with Arduino

Wiring

Wiring it up is easy, connect

GND to GND on your board

VCC to the logic level power of your board (on classic Arduinos & Metros use 5V, on 3.3V devices use 3.3V)

SDA to the SDA i2c data pin

SCL to the SCL i2c clock pin

There are internal 10K pull-ups on the PCF8523 on SDA and SCL to the VCC voltage

pcfmetro Fritzing

https://adafru.it/A1F

Talking to the RTC

The RTC is an i2c device, which means it uses 2 wires to to communicate. These two wires are used to set the time

and retrieve it.

For the RTC library, we'll be using a fork of JeeLab's excellent RTC library, which is available on GitHub. You can do

that by visiting the github repo and manually downloading or, easier go to the Arduino Library Manager