RTC module V2 for Raspberry

New version more compact !

Real Time Clock (RTC) shield to keep your Raspberry Pi always on time.

The Raspberry Pi do not provide date and time backup on board.
When you power the board without an internet connection (especialy with type A Raspberry), you don't have the current date and time.

This shield brings you a best in class RTC IC : DS1338 and a long lasting Lithium battery that allows your Rasberry Pi board to always have the correct date and time, even after reboot.

This shield have built in support in the major current Linux builds.

The RTC shield feature:

• Keep track of seconds, minutes, hours, date of the month, month, day of the week and year with Leap-Year Compensation Valid Up to 2100
• 56-Byte Battery-Backed General-Purpose RAM with Unlimited Writes
• Board connection with I ² C.
• Direct connection on the Raspberry Pi expansion connector

To enable your RTC shied on your Raspberry Pi, it's so simple:

Edit the file
sudo nano /etc/modprobe.d/raspi-blacklist.conf

Comment the line
#blacklist i2c-bcm2708

Edit the file
sudo nano /etc/modules

and add :
i2c-dev

The previous steps allow you to enable the I2C interface of the RPi. We now need to activate the support of the RTC device :
sudo bash
echo ds1338 0x68 > /sys/class/i2c-adapter/i2c-1/new_device
exit

Usage of the RTC with the linux command hwclock :

sudo hwclock –r : Read and print the RTC date and time

sudo hwclock –s : Update the linux system date and time with the content of the RTC

sudo hwclock –w : Update the RTC RTC from the system time