Echelon Neuron C - Manual (Page 38)

26 Focusing on a Single Device
initial-value An optional initial value to be loaded into the timer on
power-up or reset. Zero is loaded by the Neuron firmware (in other
words, the timer is turned off) if no explicit initial-value is supplied.
Examples
An example of declaring a timer object and assigning a value to it is shown below:
// start timer with value of 5 sec
stimer led_timer = 5;
An example of turning a timer off is shown below:
stimer led_timer;
when (some-event)
{
led_timer = 0;
}
An example of evaluating the value of a running timer is shown below:
stimer repeating led_timer;
when (some-event)
{
time_remaining = led_timer;
...
}
Note: When setting and examining timers in the NodeBuilder debugger, certain
inaccuracies could occur. When a timer is set during program execution and is
examined while the program is halted (includes single stepping and breakpoints),
the timer value can be as much as 200 milliseconds larger than the actual time
until expiration. No such inaccuracy exists on a timer that is allowed to run
without a debugger halt.
The timer_expires Event
The timer_expires event becomes TRUE when a timer expires. The syntax of this
event is the following:
timer_expires [( timer-name )]
timer-name Specifies a specific timer to check.
If timer-name is not included, the event is an unqualified timer_expires event.
An unqualified event expression is one that omits the optional qualifier syntax
that limits the objects to which the event applies.
A timer event is unique because it can be cleared only by checking for specific
(qualified) timer expiration events. Other events can be cleared by checking for
either the qualified or unqualified events. For example, the following when
clause checks for the expiration of the led_timer, so the timer_expires event for
that timer is cleared to FALSE.
Examples:
stimer led_timer;
when (timer_expires(led_timer))
{
io_out(io_led, OFF); // Turn off the LED