Basics
The Real time clock DS1307 IC basically is stand alone time clock. Well, basically we can use a micrcontroller to keep time, but the value would go off as soon as it is powered off.
A sample schematic with one master and three slaves
The RTC DS1307 is a handy solution to keep time all the way, when it is powered by a coin cell.
It is uses I²C (Inter-Integrated Circuit) protocol, referred to as I-squared-C, I-two-C, or IIC) for communication with the micrcontroller.Let see first the basics of the communication protocol first.
The I²C require only two wires for communication. One is called the Serial Data (SDA) and the other is Serial Clock (SCL) as shown.
There are various modes and configurations in which it can be used. Let us start simply with a single master and a single slave.