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RE: [avr-libc-dev] wdt_enable may fail to enable the watchdog onATmega12
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From: |
Weddington, Eric |
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Subject: |
RE: [avr-libc-dev] wdt_enable may fail to enable the watchdog onATmega1281 |
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Date: |
Mon, 31 Aug 2009 10:59:32 -0600 |
> -----Original Message-----
> From:
> address@hidden
> [mailto:address@hidden
> org] On Behalf Of Danjel McGougan
> Sent: Friday, August 28, 2009 3:03 AM
> To: address@hidden
> Subject: [avr-libc-dev] wdt_enable may fail to enable the
> watchdog onATmega1281
>
> This macro seems to depend on the fact that at least one more
> instruction will be executed after global interrupts are enabled
> before an actual interrupt can happen. But this fact seems only to be
> true for instructions using only one instruction word (16 bits).
> Instructions such as sts that use two words (32 bits) are not
> guaranteed to be executed before an interrupt may fire. I have learned
> this the hard way after trying to optimize interrupt latency in my
> application for ATmega1281. It does not seem to be documented by
> Atmel.
Have you tested this on the ATmega1281? Have you tested this on any other
ATmega device?