Descripition :

 The DS1307 serial real-time clock (RTC) is a low-power, full binary-coded decimal (BCD) clock/calendar plus 56 bytes of NV SRAM. Address and data are transferred serially through an I2C, bidirectional bus. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The end of the month date is automatically adjusted

Features :

• Real-time clock counts seconds, minutes, hours, date, month, day, year, and leap year to 2100 

• 56-bytes general-purpose NV RAM 

• Accuracy > 2 minutes/month at 25oC 

• Automatic power management circuitry 

• 2-wire serial interface 

• Programmable square wave output signal 

• Uses <300nA in backup mode with oscillator running