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Watchdog function, Ata6264 [preliminary – Atmel ATA6264 User Manual

Page 47

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47

4929B–AUTO–01/07

ATA6264 [Preliminary]

16. Watchdog Function

To verify the proper function of the microcontroller, watchdog logic is included. As the ATA6264
is powered up, the RESQ2 signal stays low until the first valid watchdog trigger is detected.

Features:

• Watchdog trigger has to be done via the serial interface

• In case of a watchdog-trigger mismatch, the ATA6264 is set into its default state (latches,

MISO status, etc.) and RESQ is set to low.

• Watchdog has to be triggered cyclically (prescaler for repetition time is set via serial interface

command). Default: 16-ms repetition time

Figure 16-1. Watchdog Trigger Functional Principle

Re-configure prescaler during
1 st and 2nd trigger watchdog

command

Serial

interface

communication

chip

internal

trigger

window

VCORE

4.8V

5.0V

16 ms

16 ms

WD cyc*

WD cyc*

4 ms

4 ms

RESQ

t

t

t

t

an

y diff

erent

SPI CMD

re-configure

prescaler

T

rg Wdg

CMD

T

rg Wdg

CMD

T

rg Wdg

CMD

* Watchdog cycle, see pages 48 and 49