2.12.1 AVR® Dx Additional Features
The AVR Dx devices have the option to configure the watchdog functionality using
Watchdog Config (WDTCFG) fuses. This option ensures the WDT can be configured to run
immediately after Reset without software support but not eliminate the need for the
Watchdog Reset (WDR
) instruction. The software must periodically
run the WDR
instruction to avoid a system reset triggered by the
WDT.
In addition to the normal operation, the AVR Dx watchdog has a Window mode. The
Window mode defines a time slot or window inside the time-out period during which
the WDT must be reset. If the WDT is reset outside this window, either too early or
too late, a system Reset will be issued. Compared to the normal operation, the
Window mode can catch situations where a code error causes constant
WDR
execution.