Maxim ds1307 series smd serial real time clocks 64 x 8 i sup2 c maxim ds1307z this real time clock rtc is a low power full binary coded decimal bcd clock calendar that also features 56 bytes of non volatile sram data communication is handled by a bidirectional i sup2 c serial interface the data supplied by the clock function includes seconds minutes hours day date month and year the device also has automatic month end adjustments for non 31 day months and for leap years the cl