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2.5.4 Wakeup Watchdog

Figure 20.

If the Timer is activated during Normal mode by setting WDEN in WDC, an “acknowledge-free” sequence is

started for a predefied programmable time. Window Watchdog activity is resumed after expiry of the timer.

To be able to detect the timeout, the corresponding interrupt enable must be set in GIEN.

This mode can also be used to allow a bootstrap loader mode with longer execution times than the maximum

specified window. Correct startup of this loader is safely detected upon missing response following the timeout.

The timer can always be restarted by rewriting WDEN twice in WDC with a new timing.

Window Wd

Window Wd

Timer (80ms .. 45min)

NINT

Ack Window &

Timeout and resume Window Wd

Interrupt active upon timeout (via GIEN)

Start Timer

restart timer

at any time

writing WDC twice