hplwdtp.nc

tinyos2.0版本驱动

module HPLWdtP 
{
    provides interface StdControl;
    provides interface WDT;
    //provides command void reset();
    //provides command result_t start(int32_t interval);
    
    uses interface Timer<TMilli> as Timer;
    //uses interface StdControl;
    //uses interface StdControl as TimerControl;
    //uses interface StdControl as WDTControl;
}

implementation
{
    int32_t increment;
    int32_t remaining;

    enum 
    {
	WDT_LATENCY = 490,
	// note that the HW watchdog is set to expire every 2
	// second; to be safe, we should kick it at least
	// twice  per expiration period
    };

    //command void StdControl.start() 
    //如果和interface StdControl的定义不同（即使是返回值类型不同），系统会认为是新定义的start，stop函数，报错如下
    //conflicting types for `StdControl.start' 和 previous declaration of `StdControl.start'
    
    command error_t StdControl.start()
    {
      wdt_enable(WDTO_1S);//see \Cygwin\usr\avr\include\avr\wdt.h @lzm
      increment = 0; 
      remaining = 1;
	  //call TimerControl.start();
	  call Timer.startPeriodic(WDT_LATENCY);
	  //call WDTControl.start();
	  return SUCCESS;
    }

    command error_t StdControl.stop() 
    {	
	  increment = 0;
	  wdt_disable();
	  //call WDTControl.stop();
	  //call TimerControl.stop();
    }

    event void Timer.fired() 
    {
	  if (increment != 0) 
	  { // Watchdog is active
	    atomic 
	    {
		  remaining = remaining - WDT_LATENCY;
	    }
	  }
	  if (remaining > 0) // the time has not yet passed. kick the dog
	    //call reset();
	      wdt_reset();
    }

    // for starters, only one watchdog per node, settable only once
    command error_t WDT.start(int32_t interval) 
    {
	  if (increment == 0) 
	  {
	    increment = interval;
	    remaining = increment;
	    return SUCCESS;
	  }
	  return FAIL;
	}


    command void WDT.reset() 
    {
	  atomic 
	  {
	    remaining = increment;
	  }
    }

}