-void timer_init(timer_type* ptimer);
-void timer_start(timer_type* ptimer, unsigned int period);
-void timer_stop(timer_type* ptimer);
-int timer_check(timer_type* ptimer);
-int timer_started(timer_type* ptimer);
-int timer_get_left(timer_type* ptimer);
-int timer_get_gone(timer_type* ptimer);
+ /** start the timer with the given period. If cyclic=true then the timer willl
+ * be reset after each period.
+ * Set period to zero if you want to disable the timer.
+ */
+ void start(float period, bool cyclic = false);
+ /** returns true if a period (or more) passed during the last tick command */
+ bool check();