A real time clock is a digital clock with a primary function to keep accurate track of time even when a power supply is turned off or if a device is placed in low power mode. RTCs are comprised of a controller, oscillator, and an embedded or external 32.768kHz quartz crystal tuning fork. They are engineered as all-in-one devices to provide better performances than discrete components, simplify integration in new designs, and accelerate time to market. Functions of the RTC are called registers. Register data is programmed into RAM memory. The registers are updated periodically, even during normal RTC operation. The RTC design also includes a power switch function to battery operation or another low power backup power source. This allows the RTC to maintain precise and continuous time counts, even if the unit goes into sleep mode or if main power is lost. It also alleviates the need for the user to reset the time and date every time the device supply is cycled. RTCs are used in a variety of applications where they play a critical role in keeping accurate track of the current time while also providing alarms, timers, and interrupt functions and helping to reduce power consumption.