Why watchdog has 8 reload registers?

[Arjun]

Could you explain why 8 reload registers exists. Its use and use case. Since I believe we need to reload every register each time we have to reset counter.

[Einar Thorsrud]

You need to reload every enabled reload request registers (RR). Thus, if you only enable RR0 (by writing 1 to RREN), you only need to write the magic word to RR0 in order to reload the WDT.

Most application will only need to use one reload request registers. However, more than one may be useful in some cases, for example if you are using a RTOS with several tasks. In that case you may want every task to request a reload of the watchdog, and trigger a system reset if any of the tasks fail to do so.