AVR-Chat

Hi guys,

Im using a Mega8 at the moment and cant quite understand whats
happening with my watchdog timer. I have never used the watchdog timer
before, but have had quite a bit of general programming experience.

Basically, I do as the datasheet says, 

I write a one to WDCE and WDE simultaneously, then in the next
instruction write 0x0F to WDTCR (2048k prescaler, WDE = 1)

But, when I try to disable the watchdog by doing the same as above,
except writing 0x00 to WDTCR, the processor resets, like a watchdog
reset. 

I disable it will within the 2seconds I should have before it expires. 

Has anyone else had issues with the watchdog timer ?

By the way, im using an 8Mhz internal oscillator, Watchdog enable fuse
not blown, so it should be under software control.

Would greatly appreciate any help !!

Cheers
Hein B
Auckland, New Zealand.

At 11:09 AM 19/06/2006, you wrote:
>Has anyone else had issues with the watchdog timer ?

This is the recommender way to turn off the WDT. I guess
you have copied your routine from the data sheet. I guess you
could do a WDR before turning it off just in case it is about
to reset. Also the bits in the MCUCSR would show if in fact it
is the WD.

WDT_off:
; Write logical one to WDCE and WDE
ldi r16, (1<<WDCE)|(1<<WDE)
out WDTCR, r16
; Turn off WDT
ldi r16, (0<<WDE)
out WDTCR, r16
ret



Regards

John Samperi

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Ampertronics Pty. Ltd.
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I would recommend a WDR before any changes.


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