Software Issues in Wireless Sensor Networks - Application and Multidisciplinary Aspects of Wireless Sensor Networks - page 36

call Leds.init();
return SUCCESS; // SUCCESS is always returned
}
// Handling of the Start command, issued by Main:
// set the rate for the clock component.
command result_t StdControl.start() {
// Start a repeating timer that fires every 1000ms
return call Timer.start(TIMER_REPEAT, 1000);

}
// Handling of the Stop command, issued by Main:
// stop the timer
command result_t StdControl.stop() {
return call Timer.stop();

}
// Handling the Fired event, issued by Timer:
// issue redToggle command to Leds
event result_t Timer.fired(){
call Leds.redToggle();
return SUCCESS;

}
}
The configuration of the Blink application can be summarized in the following
diagram (Fig. 3.3 ).

3.2.1.5 TinyOS Radio Communication

To facilitate efficient radio communication, TinyOS introduces the concept of
“Active Messages.” Active Messages effectively multiplex the access to the radio,

Main

Provider Interface

User Interface

BlinkM

Single Timer LedC

Fig. 3.3 Configuration of the Blink application