SKU : B09008 DS1307 I2C real time clock chip (RTC) 24C32 32K I2C EEPROM memory using LIR2032 rechargeable lithium battery, and a charging circuit with DS1307 with battery backup solution can not read and write. When fully charged, it can provide DS1307 timing 1 year. Compact design, 27mm * 28mm * 8.4mm lead DS1307 clock pin provides a clock signal to the microcontroller. Other I2C devices can be cascaded.