First of all, a real-time clock (RTC) is a computer clock that will keep track of the current time. You can find RTC in almost any electronic device that needs to keep accurate time.

Due to the low power consumption and free the main system for time critical tasks, the RTC is the favorable choice and always being applied into electronic device. Beside that, RTC often have an alternate source of power, and this to allow it to keep time accurately, even though the primary source of power is off or unavailable. The alternate source of power is normally a lithium battery in order systems, but some newer systems use a supercapacitor, due to they’re rechargeable and can be soldered easily! In addition, the alternate power source can supply power to battery backed RAM too.

Today’s PIC project uses a 12C Real Time Clock IC (DS1307) and four digit seven segment display to create a standard desk clock. The DS1307 (RTC) Real Time Clock IC is an 8 pin device that using a 12C interfaces. It has eight read/write registers that store some important timing information!

By the way, there is a Clock Halt (CH) bit which is bit 7 of address 0. You need to reset the CH bit to zero to let the chip operate.