ATA6612C View Datasheet(PDF) - Atmel Corporation

Part Name

Description

MFG CO.

ATA6612C

8K/16K Flash Microcontroller with LIN Transceiver, 5V Regulator and Watchdog

Atmel Corporation 

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5.8.9

Watchdog Timer

Atmel® ATA6612C/ATA6613C has an enhanced watchdog timer (WDT). The main features are:

● Clocked from separate on-chip oscillator

● 3 operating modes

● Interrupt

● System reset

● Interrupt and system reset

● Selectable time-out period from 16ms to 8s

● Possible hardware fuse watchdog always on (WDTON) for fail-safe mode

Figure 5-21. Watchdog Timer

128kHz

Oscillator

Watchdog

Prescaler

WATCHDOG

RESET

WDE

WDP0

WDP1

WDP2

WDP3

MCU RESET

WDIF

WDIE

INTERRUPT

The watchdog timer (WDT) is a timer counting cycles of a separate on-chip 128kHz oscillator. The WDT gives an interrupt or

a system reset when the counter reaches a given time-out value. In normal operation mode, it is required that the system

uses the WDR - watchdog timer reset - instruction to restart the counter before the time-out value is reached. If the system

doesn't restart the counter, an interrupt or system reset will be issued.

In Interrupt mode, the WDT gives an interrupt when the timer expires. This interrupt can be used to wake the device from

sleep-modes, and also as a general system timer. One example is to limit the maximum time allowed for certain operations,

giving an interrupt when the operation has run longer than expected. In System Reset mode, the WDT gives a reset when

the timer expires. This is typically used to prevent system hang-up in case of runaway code. The third mode, Interrupt and

system reset mode, combines the other two modes by first giving an interrupt and then switch to system reset mode. This

mode will for instance allow a safe shutdown by saving critical parameters before a system reset.

66 ATA6612C/ATA6613C [DATASHEET]

9111L–AUTO–11/14

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