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.