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[avr-libc-dev] [Bug #2419] Disabling the Watchdog
From: |
nobody |
Subject: |
[avr-libc-dev] [Bug #2419] Disabling the Watchdog |
Date: |
Tue, 28 Jan 2003 17:34:24 -0500 |
=================== BUG #2419: FULL BUG SNAPSHOT ===================
http://savannah.nongnu.org/bugs/?func=detailbug&bug_id=2419&group_id=2140
Submitted by: None Project: AVR C Runtime Library
Submitted on: 2003-Jan-28 17:34
Category: Library Severity: 5 - Major
Bug Group: None Resolution: None
Assigned to: None Originator Email: address@hidden
Status: Open
Summary: Disabling the Watchdog
Original Submission: The latest (and prior versions?) compiler generates the
following code to disable the watchdog --- wdt_disable()---:
Outside interrupt routines:
in __tmp_reg__,__SREG__
cli
wdr
out 33,r24
out __SREG__,__tmp_reg__
out 33,r18
// 33 is the WDTCR
Inside interrupt routines:
ldi r24,lo8(24)
ldi r25,hi8(24)
out 33, r24
out 33, __zero_reg__
If the user is using any watchdog timeout other than 17ms, the interrupt
version of the watchdog disable may actually cause a watchdog reset! To prevent
this, the WDR instruction should be added in front of the interrupt code as in
the non-interrupt code, or the prescaler bits should be preserved during the
disable operation. In 'C' the user can avoid the problem by issuing a
wdt_reset() instruction just before the wdt_disable() instruction.
In other words, any time you wish to disable the watchdog inside an interrupt
routine use the following:
wdt_reset();
wdt_disable();
--
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For detailed info, follow this link:
http://savannah.nongnu.org/bugs/?func=detailbug&bug_id=2419&group_id=2140
- [avr-libc-dev] [Bug #2419] Disabling the Watchdog,
nobody <=