contiki/cpu/avr/watchdog.c

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/*
* Copyright (c) 2005, Swedish Institute of Computer Science
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*
*/
/* Watchdog routines for the AVR */
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/* The default timeout of 2 seconds works on most MCUs.
* It should be disabled during sleep (unless used for wakeup) since
* it draws significant current (~5 uamp on 1284p, 20x the MCU consumption).
*
* Note the wdt is not properly simulated in AVR Studio 4 Simulator 1:
* On many devices calls to wdt_reset will have no effect, and a wdt reboot will occur.
* The MCUSR will not show the cause of a wdt reboot.
* A 1MHz clock is assumed; at 8MHz timeout occurs 8x faster than it should.
* Simulator 2 is supposed to work on supported devices (not atmega128rfa1),
* but neither it nor Studio 5 beta do any resets on the 1284p.
*
* Setting WATCHDOG_CONF_TIMEOUT -1 will disable the WDT.
*/
//#define WATCHDOG_CONF_TIMEOUT -1
#ifndef WATCHDOG_CONF_TIMEOUT
#define WATCHDOG_CONF_TIMEOUT WDTO_2S
#endif
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/* While balancing start and stop calls is a good idea, an imbalance will cause
* resets that can take a lot of time to track down.
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* Some low power protocols may cause this.
* The default is no balance; define WATCHDOG_CONF_BALANCE 1 to override.
*/
#ifndef WATCHDOG_CONF_BALANCE
#define WATCHDOG_CONF_BALANCE 0
#endif
#include "dev/watchdog.h"
#include <avr/wdt.h>
#include <avr/interrupt.h>
/* MCUSR is a deprecated name but older avr-libc versions may define it */
#if !defined (MCUCSR)
# if defined (MCUSR)
# define MCUCSR MCUSR
# endif
#endif
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#if WATCHDOG_CONF_BALANCE && WATCHDOG_CONF_TIMEOUT >= 0
static int stopped = 0;
#endif
/*---------------------------------------------------------------------------*/
void
watchdog_init(void)
{
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/* Clear startup bit and disable the wdt, whether or not it will be used.
Random code may have caused the last reset.
*/
MCUCSR&=~(1<<WDRF);
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wdt_disable();
#if WATCHDOG_CONF_BALANCE && WATCHDOG_CONF_TIMEOUT >= 0
stopped = 1;
#endif
}
/*---------------------------------------------------------------------------*/
void
watchdog_start(void)
{
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#if WATCHDOG_CONF_TIMEOUT >= 0
#if WATCHDOG_CONF_BALANCE
stopped--;
if(!stopped)
#endif
wdt_enable(WATCHDOG_CONF_TIMEOUT);
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#endif
}
/*---------------------------------------------------------------------------*/
void
watchdog_periodic(void)
{
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#if WATCHDOG_CONF_TIMEOUT >= 0
#if WATCHDOG_CONF_BALANCE
if(!stopped)
#endif
wdt_reset();
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#endif
}
/*---------------------------------------------------------------------------*/
void
watchdog_stop(void)
{
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#if WATCHDOG_CONF_TIMEOUT >= 0
#if WATCHDOG_CONF_BALANCE
stopped++;
#endif
wdt_disable();
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#endif
}
/*---------------------------------------------------------------------------*/
void
watchdog_reboot(void)
{
cli();
wdt_enable(WDTO_15MS); //wd on,250ms
while(1); //loop
}
/*---------------------------------------------------------------------------*/
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#if 0
/* Not all AVRs implement the wdt interrupt */
ISR(WDT_vect)
{
}
#endif