====== XC3/XD3/XS3 - real-time clock (RTC) support for timekeeping ======

All our 3rd generation cores XC3/XD3/XS3 are equipped with a real-time clock (RTC) chip and some sort of power buffer option for it.\\
This enables the core to keep the system time during power cycles or longer periods of ''no power''.

===== XC3/XD3 - battery slot =====

All XC3 and XD3 cores are internally equipped with a **CR2032** battery slot for the RTC chip (by default no battery is installed from factory). \\ 
When a **CR2032** standard button cell battery is inserted into that slot the RTC chip will be enabled.\\ \\

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**Important**\\  
Installing the battery can not be done during operation of the core and reqires advanced maintenance including opening the core and breaking the WARRANTY seal.\\
\\ 
Please ask your local dealer for futher instructions before starting to install a battery.
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After the battery was installed, it is initially required that the core is synced once to a valid NTP time source.\\
This will start the timekeeping and from now on the time will be kept automatically.

If no battery is installed the current system time will be lost after a power cycle.


===== XS3 - backup capacitor =====
All XS3 cores are equipped with a backup capacitor which powers the RTC chip for timekeeping. No battery is required.\\ \\
To start the timekeeping it is initially required that the core is synced once to a valid NTP time source.\\
Afterwards the time will be kept automatically for approximately 7 days.