Description On board 0.91” OLED, 128×32 pixels, configure as IIC interface, drive by SSD1306. Color Blue. On board AT24C02 small size EEPROM (256 bytes), can save a few data for user On board DS1307 RTC clock, with backup battery holder. On board logic shifter and 5V-3.3V regulator, can use 5V logic and power supply, or 3V group logic and power supply. Reserved DS18B20 temperature sensor socket, output to DQ pin. Two groups of 3.3V, GND, SCL, SDA IIC interface, cascadable design, can connect as many IIC devices as you want. Interface: two groups pins: 3.3V GND, SCL, SDA (3.3V logic) DQ, SQ, BAT pin: DS18B20 one wire output pin DQ, DS1307 time output pin SQ, DS1307 backup battery pin BAT. 5V GND, SCL SDA (5V logic). LDO supply up to 500mA/16V. Read write EEPROM, print data to OLED demo sketch here.   (https://github.com/Edragon/Arduino/tree/master/arduino-env/Sketchbook/Interface/IIC-MISC/OLED-12832) Schematic see here.