RTC DS3231 + EEPROM ATC02 module, with battery

This dual function module uses the extremely accurate ( error value of 1-2 ppm ) DS3231 clock chip with a 2kb memory module ( with 8 address options ) and has a CR-1220 battery back-up included. Extremely easy to use with I2C connections and readily available code library’s in the arduino IDE, this module can be powered by either 3.3V or 5V and is suitable for both logic levels without the need for logic level shifting.

NOTE : There are no pull-up resistors on the I2C data lines, this allows you to connect the required I2C pull-up resistors separately.