FreeRTOS::StaticTimer Class Reference

Class that encapsulates the functionality of a FreeRTOS timer. More...

#include <Timer.hpp>

Inheritance diagram for FreeRTOS::StaticTimer:

Collaboration diagram for FreeRTOS::StaticTimer:

Public Member Functions
	StaticTimer (const StaticTimer &)=delete
StaticTimer &	operator= (const StaticTimer &)=delete
Public Member Functions inherited from FreeRTOS::TimerBase
	TimerBase (const TimerBase &)=delete
TimerBase &	operator= (const TimerBase &)=delete
virtual void	timerEntry () final
	Function that acts as the entry point of the timer instance.
bool	isValid () const
	Function that checks the value of the timer handle. This function should be called to ensure the timer was created successfully.
bool	isActive () const
	Function that calls BaseType_t xTimerIsTimerActive( TimerHandle_t xTimer )
bool	start (const TickType_t blockTime=0) const
	Function that calls BaseType_t xTimerStart( TimerHandle_t xTimer, TickType_t xBlockTime )
bool	startFromISR (bool &higherPriorityTaskWoken) const
	Function that calls BaseType_t xTimerStartFromISR( TimerHandle_t xTimer, BaseType_t *pxHigherPriorityTaskWoken )
bool	startFromISR () const
	Function that calls BaseType_t xTimerStartFromISR( TimerHandle_t xTimer, BaseType_t *pxHigherPriorityTaskWoken )
bool	stop (const TickType_t blockTime=0) const
	Function that calls BaseType_t xTimerStop( TimerHandle_t xTimer, TickType_t xBlockTime )
bool	stopFromISR (bool &higherPriorityTaskWoken) const
	Function that calls BaseType_t xTimerStopFromISR( TimerHandle_t xTimer, BaseType_t *pxHigherPriorityTaskWoken )
bool	stopFromISR () const
	Function that calls BaseType_t xTimerStopFromISR( TimerHandle_t xTimer, BaseType_t *pxHigherPriorityTaskWoken )
bool	changePeriod (const TickType_t newPeriod, const TickType_t blockTime=0) const
	Function that calls BaseType_t xTimerChangePeriod( TimerHandle_t xTimer, TickType_t xNewPeriod, TickType_t xBlockTime )
bool	changePeriodFromISR (bool &higherPriorityTaskWoken, const TickType_t newPeriod) const
	Function that calls BaseType_t xTimerChangePeriodFromISR( TimerHandle_t xTimer, TickType_t xNewPeriod, BaseType_t *pxHigherPriorityTaskWoken )
bool	changePeriodFromISR (const TickType_t newPeriod) const
	Function that calls BaseType_t xTimerChangePeriodFromISR( TimerHandle_t xTimer, TickType_t xNewPeriod, BaseType_t *pxHigherPriorityTaskWoken )
bool	deleteTimer (const TickType_t blockTime=0)
	Function that calls BaseType_t xTimerDelete( TimerHandle_t xTimer, TickType_t xBlockTime )
bool	reset (const TickType_t blockTime=0) const
	Function that calls BaseType_t xTimerReset( TimerHandle_t xTimer, TickType_t xBlockTime )
bool	resetFromISR (bool &higherPriorityTaskWoken) const
	Function that calls BaseType_t xTimerResetFromISR( TimerHandle_t xTimer, BaseType_t *pxHigherPriorityTaskWoken )
bool	resetFromISR () const
	Function that calls BaseType_t xTimerResetFromISR( TimerHandle_t xTimer, BaseType_t *pxHigherPriorityTaskWoken )
void	setReloadMode (const bool autoReload) const
	Function that calls void vTimerSetReloadMode( TimerHandle_t xTimer, const UBaseType_t xAutoReload )
const char *	getName () const
	Function that calls const char * pcTimerGetName( TimerHandle_t xTimer )
TickType_t	getPeriod () const
	Function that calls TickType_t xTimerGetPeriod( TimerHandle_t xTimer )
TickType_t	getExpiryTime () const
	Function that calls TickType_t xTimerGetExpiryTime( TimerHandle_t xTimer )
bool	getReloadMode () const
	Function that calls UBaseType_t uxTimerGetReloadMode( TimerHandle_t xTimer )
void	setDeleteBlockTime (const TickType_t deleteBlockTime=0)
	Set the delete block time. This value is used when the destructor calls deleteTimer().
TickType_t	getDeleteBlockTime () const
	Set the delete block time. This value is used when the destructor calls deleteTimer().

Protected Member Functions
	StaticTimer (const TickType_t period, const bool autoReload=false, const char *name="", const TickType_t deleteBlockTime=0)
	Construct a new StaticTimer object by calling TimerHandle_t xTimerCreateStatic( const char * const pcTimerName, const TickType_t xTimerPeriod, const UBaseType_t xAutoReload, void * const pvTimerID, TimerCallbackFunction_t pxCallbackFunction StaticTimer_t *pxTimerBuffer )
	StaticTimer (StaticTimer &&) noexcept=default
StaticTimer &	operator= (StaticTimer &&) noexcept=default
Protected Member Functions inherited from FreeRTOS::TimerBase
virtual void	timerFunction ()=0
	Abstraction function that acts as the entry point of the timer callback for the user.

Private Attributes
StaticTimer_t	staticTimer

Additional Inherited Members
Static Public Member Functions inherited from FreeRTOS::TimerBase
static void *	operator new (size_t)=delete
static void *	operator new[] (size_t)=delete
static void *	operator new (size_t, void *ptr)
static void *	operator new[] (size_t, void *ptr)

Detailed Description

Class that encapsulates the functionality of a FreeRTOS timer.

Timer Timer.hpp <FreeRTOS/Timer.hpp>

Each software timer requires a small amount of RAM that is used to hold the timer's state. If a timer is created using FreeRTOS::Timer() then this RAM is automatically allocated from the FreeRTOS heap. If a software timer is created this class then the RAM is included in the object so it can be statically allocated at compile time. See the Static Vs Dynamic allocation page for more information.

Note

This class is not intended to be instantiated by the user. The user should create a class that derives from this class and implement timerFunction().

Warning

This class contains the timer data structure, so any instance of this class or class derived from this class should be persistent (not declared on the stack of another function).

Constructor & Destructor Documentation

StaticTimer()

FreeRTOS::StaticTimer::StaticTimer ( const TickType_t  period, const bool  autoReload = false, const char *  name = "", const TickType_t  deleteBlockTime = 0  )

inlineexplicitprotected

Construct a new StaticTimer object by calling TimerHandle_t xTimerCreateStatic( const char * const pcTimerName, const TickType_t xTimerPeriod, const UBaseType_t xAutoReload, void * const pvTimerID, TimerCallbackFunction_t pxCallbackFunction StaticTimer_t *pxTimerBuffer )

Timer.hpp

See also

https://www.freertos.org/xTimerCreateStatic.html

Note

When calling xTimerCreateStatic the constructor passes the this pointer as the pvTimerID argument. This pointer is used so that the interface function callTimerFunction() can invoke timerFunction() for this instance of the class.

Timers are created in the dormant state. The start(), reset(), startFromISR(), resetFromISR(), changePeriod() and changePeriodFromISR() API functions can all be used to transition a timer into the active state.

Parameters

period	The period of the timer. The period is specified in ticks, and the macro pdMS_TO_TICKS() can be used to convert a time specified in milliseconds to a time specified in ticks. For example, if the timer must expire after 100 ticks, then simply set period to 100. Alternatively, if the timer must expire after 500ms, then set period to pdMS_TO_TICKS( 500 ). pdMS_TO_TICKS() can only be used if configTICK_RATE_HZ is less than or equal to 1000. The timer period must be greater than 0.
autoReload	If autoReload is set to true, then the timer will expire repeatedly with a frequency set by the period parameter. If autoReload is set to false, then the timer will be a one-shot and enter the dormant state after it expires.
name	A human readable text name that is assigned to the timer. This is done purely to assist debugging. The RTOS kernel itself only ever references a timer by its handle, and never by its name.
deleteBlockTime	Specifies the time, in ticks, that the calling task should be held in the Blocked state to wait for the delete command to be successfully sent to the timer command queue, should the queue already be full when the destructor is called. deleteBlockTime is ignored if the destructor is called before the RTOS scheduler is started or if the timer has already been deleted by deleteTimer() before the destructor is called. This value can be updated by calling setDeleteBlockTime().

Example Usage

#include <FreeRTOS/Kernel.hpp>
#include <FreeRTOS/Timer.hpp>
 
constexpr size_t numberOfTimers = 5;
 
class MyTimer : public FreeRTOS::StaticTimer {
 public:
  MyTimer() : FreeRTOS::StaticTimer(0, true, "Timer") {}
  void timerFunction() final;
 
 private:
  uint8_t count = 0;
};
 
// Define a callback function that will be used by multiple timer instances. The
// callback function does nothing but count the number of times the associated
// timer expires, and stop the timer once the timer has expired 10 times.
void MyTimer::timerFunction() {
  constexpr uint8_t maxExpiryCountBeforeStopping = 10;
 
  // Optionally do something if the pxTimer parameter is NULL.
  configASSERT(!isValid());
 
  // Increment the count, then test to see if the timer has expired
  // maxExpiryCountBeforeStopping yet.
  count++;
 
  // If the timer has expired 10 times then stop it from running.
  if (count++ >= maxExpiryCountBeforeStopping) {
    // Do not use a block time if calling a timer API function from a timer
    // callback function, as doing so could cause a deadlock!
    stop();
  }
}
 
// An array of FreeRTOS::StaticTimer objects, which are used to store the state
// of each created timer.
static MyTimer xTimers[numberOfTimers];
 
int aFunction() {
  // Initialize then start some timers.  Starting the timers before the RTOS
  // scheduler has been started means the timers will start running immediately
  // that the RTOS scheduler starts.
  for (size_t x = 0; x < numberOfTimers; x++) {
    if (xTimers[x].isValid()) {
      xTimers[x].changePeriod((100 * x) + 100);
      if (!xTimers[x].start()) {
        // The timer could not be set into the Active state.
      }
    } else {
      // The timer was not created.
    }
  }
 
  // Create tasks here.
 
  // Starting the RTOS scheduler will start the timers running as they have
  // already been set into the active state.
  FreeRTOS::Kernel::startScheduler();
 
  // Should not reach here.
  for (;;) {
    ;
  }
}

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The documentation for this class was generated from the following file:

• /home/runner/work/FreeRTOS-Cpp/FreeRTOS-Cpp/FreeRTOS-Cpp/include/FreeRTOS/Timer.hpp