Windows CE supports a hardware watchdog implementation. The watchdog's properties can be set through two exported kernel variables; dwOEMWatchDogPeriod (to set the period in ms between feeding the dog) and dwNKWatchDogThreadPriority (to set the priority of the watchdog thread).

Unfortunately, dwNKWatchDogThreadPriority is not defined... Looks like somebody at Microsoft made a typo; the name of the exported variable is dwdwNKWatchDogThreadPriority (note the double 'dw').

Here's some example code to setup the watchdog:

extern DWORD dwOEMWatchDogPeriod;
extern DWORD dwdwNKWatchDogThreadPriority;

dwOEMWatchDogPeriod = 5000;
dwdwNKWatchDogThreadPriority = 100;
pfnOEMRefreshWatchDog = RefreshWatchdogTimer;

void RefreshWatchdogTimer(void)
    static BOOL bFirstTime = TRUE;
    OALMSG(OAL_FUNC, (L"+RefreshWatchdogTimer\r\n"));
    if (bFirstTime)
        OALMSG(OAL_FUNC, (L"+RefreshWatchdogTimer: First call; init the Watchdog to timeout reset in %d secs\r\n", WD_RESET_PERIOD/1000));
        bFirstTime = FALSE;
        OALMSG(OAL_FUNC, (L"+RefreshWatchdogTimer: Subsequent calls; refresh the Watchdog timeout to %d secs again\r\n", WD_RESET_PERIOD/1000));
    OALMSG(OAL_FUNC, (L"-RefreshWatchdogTimer\r\n"));

Of course WatchdogInit and WatchdogFeed are functions implemented to initialize and feed your hardware watchdog.