cpu/msp430/watchdog.c

   1 /*
   2  * Copyright (c) 2005, Swedish Institute of Computer Science
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the Institute nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * This file is part of the Contiki operating system.
  30  *
  31  * @(#)$Id: watchdog.c,v 1.5 2008/02/11 10:45:19 adamdunkels Exp $
  32  */
  33 #include <io.h>
  34 #include "dev/watchdog.h"
  35
  36 static int stopped = 0;
  37 /*---------------------------------------------------------------------------*/
  38 void
  39 watchdog_init(void)
  40 {
  41   /* The MSP430 watchdog is enabled at boot-up, so we stop it during
  42      initialization. */
  43   stopped = 0;
  44   watchdog_stop();
  45 }
  46 /*---------------------------------------------------------------------------*/
  47 void
  48 watchdog_start(void)
  49 {
  50   /* We setup the watchdog to reset the device after one second,
  51      unless watchdog_periodic() is called. */
  52   stopped--;
  53   if(!stopped) {
  54     WDTCTL = WDTPW | WDTCNTCL | WDT_ARST_1000;
  55   }
  56 }
  57 /*---------------------------------------------------------------------------*/
  58 void
  59 watchdog_periodic(void)
  60 {
  61   /* This function is called periodically to restart the watchdog
  62      timer. */
  63   if(!stopped) {
  64     WDTCTL = (WDTCTL & 0xff) | WDTPW | WDTCNTCL;
  65   }
  66 }
  67 /*---------------------------------------------------------------------------*/
  68 void
  69 watchdog_stop(void)
  70 {
  71   WDTCTL = WDTPW | WDTHOLD;
  72   stopped++;
  73 }
  74 /*---------------------------------------------------------------------------*/
  75 void
  76 watchdog_reboot(void)
  77 {
  78   WDTCTL = 0;
  79 }
  80 /*---------------------------------------------------------------------------*/