The RTC is a time registering device to keep track of time in industrial or PC application. It is able to keep time even when the device is turned off. The RTC is connected to a small battery (which usually has a long lifespan, 5 or more years). Specifically, the RTC maintains the second, minute, hour, day, year, and century for the system.
The RTC is incorporated into the same chip as the computer's CMOS (complementary metal-oxide semiconductor). The RTC goes into action when the system is started. During the start-up process, the basic input/output system checks the RTC for the current time and passes that information along to the operating system's clock. The operating system synchronizes its own clock to match the date and time given to it by the RTC. After that, the operating system uses its clock to measure time until the system is shut down.
Epson offers a wide range of real-time clock (Rtcs) :
Serial 4-wire module is a serial interface real time clock that has a built-in industrial crystal unit.
Serial 3-wire module is a serial interface real time clock that has a built-in crystal unit.
I2C-Bus module has an interface real time clock that has a built-in crystal unit.
Parallel 4-bit module is a parallel interface real time clock that has a built-in crystal unit.
