RM 10.00
Features :
+ 24C32 32K I2C EEPROM Memory
+ DS1307 based RTC with LIR2032 battery
+ Backup by AT24C32 32Kbit
+ DS1307,AT24C32 can work separated
+ Leads to the DS1307 clock pin, to provide the clock signal for the microcontroller

+ DE4205-sample.zip
+ AT24C32.pdf
+ DS1307.pdf

Pin out is as written on the board, on the left hand side from the top of the picture:

1. Dallas one wire (not used)
2. SCL (I2C bus clock)
3. SDA (I2C bus data)
4. VCC (+5V)
5. Ground.

This is all you actually need to use both the clock and the EEPROM. On the other side there s:

1. SQ, Square wave output, if set, can be set to run at 1Hz, 4KHz, 8KHz or 32KHz.
2. DS, as above, Dallas one wire bus not used.
3. SCL (I2C bus clock)
4. SDA (I2C bus data)
5. VCC (+5V)
6. Ground.
7. Batt. This allows you to monitor the battery voltage, see notes below.

These units work well with Arduinos, it is as simple as connecting 4 wires, +V, ground, and the two I2C bus wires which gives access to both the real time clock and EEPROM. The real time clock will not run unless initialised (It keeps it's data in RAM which can be cleared by removing the battery which also de initialises it).

Package included : RTC I2C DS1307 and 24C32 EEPROM x 1 unit