What is the main function of Window Watchdog Timer (WWDT)?

[a_ziliu]

The Window Watchdog Timer (WWDT) protects the entire system by restarting the chip when the program is unable to control due to unexpected errors during the execution of the program and the WwDT counter is reset incorrectly.
The WWDT has a 6-bit counter, and a settable Reload Window. During operation, the WWDT will ask the program to reset the counter in the Reload Window. When the program does not reset the counter in the Reload Window, or the counter counts down to 0, the program is in an uncontrollable state; at this time, the WWDT will restart the system, as shown below: