Sparkfun Real Time Clock Module DS1307

This custom designed module uses the DS1307 Real Time Clock to keep track of the current year, month, day as well as the current time. The module comes fully assembled and pre-programmed with the current time (OK, so it's MST current time). The included Lithium coin cell battery (CR1225 41mAh) will run the module for a minimum of 9 years (17 years typical) without external 5V power. The DS1307 is accessed via the I2C protocol.

Sparkfun have written a test-bed to program the modules. This test-bed code should give you some insight on how to interface the module to any micro-controller using our example software I2C and BCD routines.


  • Two wire I2C interface
  • Hour : Minutes : Seconds AM/PM
  • Day Month, Date - Year
  • Leap year compensation
  • Accurate calendar up to year 2100
  • Battery backup included
  • 1Hz output pin
  • 56 Bytes of Non-volatile memory available to user

Dimensions: 0.75x0.75" (20x20mm)


RTC Module Schematic
DS1307 Datasheet
Wiring Example


Example 16F88 code
Arduino Tutorial. Thanks John Vaughters!
Arduino Tutorial in Portuguese. Thanks Daniel Gonçalves!
Bildr Arduino Tutorial

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Sparkfun Real Time Clock Module DS1307

  • Manufacturer: SparkFun
  • Product Code: DS1307
  • Stock Quantity:  6
      - Backorder not allowed
  • £13.38

  • Ex Tax: £11.15


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Tags: Real, Time, Clock, Module, DS1307, BOB-12708, rtc, date, battery, back-up, i2c, protocol, BOB-00099, real time clock, SparkFun,