Timer
[Core]

The Timer subsystem provides a timer in a millisecond timeframe. More...


Functions

int Timer_SetActive (bool active)
 Controls the active state of the Timer subsystem.
int Timer_GetActive ()
 Returns whether the timer subsystem is active or not.
void Timer_InitializeEntry (TimerEntry *timerEntry, void(*timerCallback)(int id), int id, int timeMs, bool repeat)
 Initializes a new timer structure.
int Timer_Set (TimerEntry *timerEntry)
 Sets a given TimerEntry to run.
int Timer_Cancel (TimerEntry *timerEntry)
 Cancel a timer event.

Detailed Description

The Timer subsystem provides a timer in a millisecond timeframe.

For higher resolution timing, check the Fast Timer

The Timer subsystem is based on a collection of TimerEntries. To start a new timer, create a new TimerEntry structure, initialize it with Timer_InitializeEntry( ), and start it with Timer_Set( ).

There are currently a couple of limitations to the Timer system:

Todo:
Allow the timer callbacks to cooperate with the RTOS

Allow existing timer entries to be modified (repeat or not, modify the period, etc.)

Function Documentation

int Timer_Cancel ( TimerEntry *  timerEntry  ) 

Cancel a timer event.

Parameters:
timerEntry The entry to be removed.
Returns:
0 on success.
See also:
Timer_Set

Definition at line 218 of file timer.c.

int Timer_GetActive ( void   ) 

Returns whether the timer subsystem is active or not.

Returns:
active.
See also:
Timer_Set, Timer_Cancel

Definition at line 97 of file timer.c.

void Timer_InitializeEntry ( TimerEntry *  timerEntry,
void(*)(int id)  timerCallback,
int  id,
int  timeMs,
bool  repeat 
)

Initializes a new timer structure.

The event is signified by a callback to the function provided, after the interval specified. The specified ID is passed back to the function to permit one function to work for many events. Pass repeat = true to make the event continue to create callbacks until it is canceled.

Parameters:
timerEntry pointer to the TimerEntry to be intialized.
timerCallback pointer to the callback function. The function must be of the form 
void timerCallback( int id )
id An integer specifying the ID the callback function is to be provided with.
timeMs The time in milliseconds desired for the callback.
repeat Set whether the timer repeats or is a one-time event.
See also:
Timer_Cancel
Example
  TimerEntry myTimer; // our TimerEntry
  Timer_InitializeEntry( &myTimer, myCallback, 0, 250, true );
  Timer_Set( &myTimer ); // start our timer

  void myCallback( int id ) // our code that will get called by the timer every 250 ms.
  {
    // do something here
  }

Definition at line 127 of file timer.c.

int Timer_Set ( TimerEntry *  timerEntry  ) 

Sets a given TimerEntry to run.

This routine adds the entry to the running queue and then decides if it needs to start the timer (if it's not running) or alter the timer's clock for a shorter period.

Parameters:
timerEntry pointer to the FastTimerEntry to be run.

Definition at line 147 of file timer.c.

int Timer_SetActive ( bool  active  ) 

Controls the active state of the Timer subsystem.

Parameters:
active whether this subsystem is active or not
Returns:
Zero on success.
See also:
Timer_Set, Timer_Cancel

Definition at line 68 of file timer.c.