ATXMEGA8E5_14 datasheet(27/147 Pages) ATMEL

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XMEGA E5 [DATASHEET]

Atmel-8153I–AVR-ATxmega8E5-ATxmega16E5-ATxmega32E5_Datasheet–08/2014

14.

WDT – Watchdog Timer

14.1

Features

Issues a device reset if the timer is not reset before its timeout period

Asynchronous operation from dedicated oscillator

1kHz output of the 32kHz ultra low power oscillator

11 selectable timeout periods, from 8ms to 8s

Two operation modes:

Normal mode

Window mode

Configuration lock to prevent unwanted changes

14.2

Overview

The watchdog timer (WDT) is a system function for monitoring correct program operation. It makes it possible to recover

from error situations such as runaway or deadlocked code. The WDT is a timer, configured to a predefined timeout

period, and is constantly running when enabled. If the WDT is not reset within the timeout period, it will issue a

microcontroller reset. The WDT is reset by executing the WDR (watchdog timer reset) instruction from the application

code.

The window mode makes it possible to define a time slot or window inside the total timeout period during which 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 mode, this can also catch situations where a code error causes constant WDR execution.

The WDT will run in active mode and all sleep modes, if enabled. It is asynchronous, runs from a CPU-independent clock

source, and will continue to operate to issue a system reset even if the main clocks fail.

The configuration change protection mechanism ensures that the WDT settings cannot be changed by accident. For

increased safety, a fuse for locking the WDT settings is also available.

ATXMEGA8E5 bảng dữ liệu(PDF) 27 Page - ATMEL Corporation