Google Git
Sign in
pigweed / third_party / github / FreeRTOS / FreeRTOS-Kernel / 9af72db3ec82993df2f50170bccdf2958ad19137 / . / include / timers.h
blob: c63bfeb3cb5bd1456e64913e4adc68ec9055f61d [file] [log] [blame]
/*
* FreeRTOS Kernel <DEVELOPMENT BRANCH>
* Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* SPDX-License-Identifier: MIT
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* https://www.FreeRTOS.org
* https://github.com/FreeRTOS
*
*/
#ifndef TIMERS_H
#define TIMERS_H
#ifndef INC_FREERTOS_H
#error "include FreeRTOS.h must appear in source files before include timers.h"
#endif
/*lint -save -e537 This headers are only multiply included if the application code
* happens to also be including task.h. */
#include "task.h"
/*lint -restore */
/* *INDENT-OFF* */
#ifdef __cplusplus
extern "C" {
#endif
/* *INDENT-ON* */
/*-----------------------------------------------------------
* MACROS AND DEFINITIONS
*----------------------------------------------------------*/
/* IDs for commands that can be sent/received on the timer queue. These are to
* be used solely through the macros that make up the public software timer API,
* as defined below. The commands that are sent from interrupts must use the
* highest numbers as tmrFIRST_FROM_ISR_COMMAND is used to determine if the task
* or interrupt version of the queue send function should be used. */
#define tmrCOMMAND_EXECUTE_CALLBACK_FROM_ISR ( ( BaseType_t ) -2 )
#define tmrCOMMAND_EXECUTE_CALLBACK ( ( BaseType_t ) -1 )
#define tmrCOMMAND_START_DONT_TRACE ( ( BaseType_t ) 0 )
#define tmrCOMMAND_START ( ( BaseType_t ) 1 )
#define tmrCOMMAND_RESET ( ( BaseType_t ) 2 )
#define tmrCOMMAND_STOP ( ( BaseType_t ) 3 )
#define tmrCOMMAND_CHANGE_PERIOD ( ( BaseType_t ) 4 )
#define tmrCOMMAND_DELETE ( ( BaseType_t ) 5 )
#define tmrFIRST_FROM_ISR_COMMAND ( ( BaseType_t ) 6 )
#define tmrCOMMAND_START_FROM_ISR ( ( BaseType_t ) 6 )
#define tmrCOMMAND_RESET_FROM_ISR ( ( BaseType_t ) 7 )
#define tmrCOMMAND_STOP_FROM_ISR ( ( BaseType_t ) 8 )
#define tmrCOMMAND_CHANGE_PERIOD_FROM_ISR ( ( BaseType_t ) 9 )
/**
* Type by which software timers are referenced. For example, a call to
* xTimerCreate() returns an TimerHandle_t variable that can then be used to
* reference the subject timer in calls to other software timer API functions
* (for example, xTimerStart(), xTimerReset(), etc.).
*/
struct tmrTimerControl; /* The old naming convention is used to prevent breaking kernel aware debuggers. */
typedef struct tmrTimerControl * TimerHandle_t;
/*
* Defines the prototype to which timer callback functions must conform.
*/
typedef void (* TimerCallbackFunction_t)( TimerHandle_t xTimer );
/*
* Defines the prototype to which functions used with the
* xTimerPendFunctionCallFromISR() function must conform.
*/
typedef void (* PendedFunction_t)( void *,
uint32_t );
/**
* TimerHandle_t xTimerCreate( const char * const pcTimerName,
* TickType_t xTimerPeriodInTicks,
* UBaseType_t uxAutoReload,
* void * pvTimerID,
* TimerCallbackFunction_t pxCallbackFunction );
*
* Creates a new software timer instance, and returns a handle by which the
* created software timer can be referenced.
*
* Internally, within the FreeRTOS implementation, software timers use a block
* of memory, in which the timer data structure is stored. If a software timer
* is created using xTimerCreate() then the required memory is automatically
* dynamically allocated inside the xTimerCreate() function. (see
* https://www.FreeRTOS.org/a00111.html). If a software timer is created using
* xTimerCreateStatic() then the application writer must provide the memory that
* will get used by the software timer. xTimerCreateStatic() therefore allows a
* software timer to be created without using any dynamic memory allocation.
*
* Timers are created in the dormant state. The xTimerStart(), xTimerReset(),
* xTimerStartFromISR(), xTimerResetFromISR(), xTimerChangePeriod() and
* xTimerChangePeriodFromISR() API functions can all be used to transition a
* timer into the active state.
*
* @param pcTimerName A text name that is assigned to the timer. This is done
* purely to assist debugging. The kernel itself only ever references a timer
* by its handle, and never by its name.
*
* @param xTimerPeriodInTicks The timer period. The time is defined in tick
* periods so the constant portTICK_PERIOD_MS can be used to convert a time that
* has been specified in milliseconds. For example, if the timer must expire
* after 100 ticks, then xTimerPeriodInTicks should be set to 100.
* Alternatively, if the timer must expire after 500ms, then xPeriod can be set
* to ( 500 / portTICK_PERIOD_MS ) provided configTICK_RATE_HZ is less than or
* equal to 1000. Time timer period must be greater than 0.
*
* @param uxAutoReload If uxAutoReload is set to pdTRUE then the timer will
* expire repeatedly with a frequency set by the xTimerPeriodInTicks parameter.
* If uxAutoReload is set to pdFALSE then the timer will be a one-shot timer and
* enter the dormant state after it expires.
*
* @param pvTimerID An identifier that is assigned to the timer being created.
* Typically this would be used in the timer callback function to identify which
* timer expired when the same callback function is assigned to more than one
* timer.
*
* @param pxCallbackFunction The function to call when the timer expires.
* Callback functions must have the prototype defined by TimerCallbackFunction_t,
* which is "void vCallbackFunction( TimerHandle_t xTimer );".
*
* @return If the timer is successfully created then a handle to the newly
* created timer is returned. If the timer cannot be created because there is
* insufficient FreeRTOS heap remaining to allocate the timer
* structures then NULL is returned.
*
* Example usage:
* @verbatim
* #define NUM_TIMERS 5
*
* // An array to hold handles to the created timers.
* TimerHandle_t xTimers[ NUM_TIMERS ];
*
* // An array to hold a count of the number of times each timer expires.
* int32_t lExpireCounters[ NUM_TIMERS ] = { 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 vTimerCallback( TimerHandle_t pxTimer )
* {
* int32_t lArrayIndex;
* const int32_t xMaxExpiryCountBeforeStopping = 10;
*
* // Optionally do something if the pxTimer parameter is NULL.
* configASSERT( pxTimer );
*
* // Which timer expired?
* lArrayIndex = ( int32_t ) pvTimerGetTimerID( pxTimer );
*
* // Increment the number of times that pxTimer has expired.
* lExpireCounters[ lArrayIndex ] += 1;
*
* // If the timer has expired 10 times then stop it from running.
* if( lExpireCounters[ lArrayIndex ] == xMaxExpiryCountBeforeStopping )
* {
* // Do not use a block time if calling a timer API function from a
* // timer callback function, as doing so could cause a deadlock!
* xTimerStop( pxTimer, 0 );
* }
* }
*
* void main( void )
* {
* int32_t x;
*
* // Create then start some timers. Starting the timers before the scheduler
* // has been started means the timers will start running immediately that
* // the scheduler starts.
* for( x = 0; x < NUM_TIMERS; x++ )
* {
* xTimers[ x ] = xTimerCreate( "Timer", // Just a text name, not used by the kernel.
* ( 100 * x ), // The timer period in ticks.
* pdTRUE, // The timers will auto-reload themselves when they expire.
* ( void * ) x, // Assign each timer a unique id equal to its array index.
* vTimerCallback // Each timer calls the same callback when it expires.
* );
*
* if( xTimers[ x ] == NULL )
* {
* // The timer was not created.
* }
* else
* {
* // Start the timer. No block time is specified, and even if one was
* // it would be ignored because the scheduler has not yet been
* // started.
* if( xTimerStart( xTimers[ x ], 0 ) != pdPASS )
* {
* // The timer could not be set into the Active state.
* }
* }
* }
*
* // ...
* // Create tasks here.
* // ...
*
* // Starting the scheduler will start the timers running as they have already
* // been set into the active state.
* vTaskStartScheduler();
*
* // Should not reach here.
* for( ;; );
* }
* @endverbatim
*/
#if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
TimerHandle_t xTimerCreate( const char * const pcTimerName, /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
const TickType_t xTimerPeriodInTicks,
const UBaseType_t uxAutoReload,
void * const pvTimerID,
TimerCallbackFunction_t pxCallbackFunction ) PRIVILEGED_FUNCTION;
#endif
/**
* TimerHandle_t xTimerCreateStatic(const char * const pcTimerName,
* TickType_t xTimerPeriodInTicks,
* UBaseType_t uxAutoReload,
* void * pvTimerID,
* TimerCallbackFunction_t pxCallbackFunction,
* StaticTimer_t *pxTimerBuffer );
*
* Creates a new software timer instance, and returns a handle by which the
* created software timer can be referenced.
*
* Internally, within the FreeRTOS implementation, software timers use a block
* of memory, in which the timer data structure is stored. If a software timer
* is created using xTimerCreate() then the required memory is automatically
* dynamically allocated inside the xTimerCreate() function. (see
* https://www.FreeRTOS.org/a00111.html). If a software timer is created using
* xTimerCreateStatic() then the application writer must provide the memory that
* will get used by the software timer. xTimerCreateStatic() therefore allows a
* software timer to be created without using any dynamic memory allocation.
*
* Timers are created in the dormant state. The xTimerStart(), xTimerReset(),
* xTimerStartFromISR(), xTimerResetFromISR(), xTimerChangePeriod() and
* xTimerChangePeriodFromISR() API functions can all be used to transition a
* timer into the active state.
*
* @param pcTimerName A text name that is assigned to the timer. This is done
* purely to assist debugging. The kernel itself only ever references a timer
* by its handle, and never by its name.
*
* @param xTimerPeriodInTicks The timer period. The time is defined in tick
* periods so the constant portTICK_PERIOD_MS can be used to convert a time that
* has been specified in milliseconds. For example, if the timer must expire
* after 100 ticks, then xTimerPeriodInTicks should be set to 100.
* Alternatively, if the timer must expire after 500ms, then xPeriod can be set
* to ( 500 / portTICK_PERIOD_MS ) provided configTICK_RATE_HZ is less than or
* equal to 1000. The timer period must be greater than 0.
*
* @param uxAutoReload If uxAutoReload is set to pdTRUE then the timer will
* expire repeatedly with a frequency set by the xTimerPeriodInTicks parameter.
* If uxAutoReload is set to pdFALSE then the timer will be a one-shot timer and
* enter the dormant state after it expires.
*
* @param pvTimerID An identifier that is assigned to the timer being created.
* Typically this would be used in the timer callback function to identify which
* timer expired when the same callback function is assigned to more than one
* timer.
*
* @param pxCallbackFunction The function to call when the timer expires.
* Callback functions must have the prototype defined by TimerCallbackFunction_t,
* which is "void vCallbackFunction( TimerHandle_t xTimer );".
*
* @param pxTimerBuffer Must point to a variable of type StaticTimer_t, which
* will be then be used to hold the software timer's data structures, removing
* the need for the memory to be allocated dynamically.
*
* @return If the timer is created then a handle to the created timer is
* returned. If pxTimerBuffer was NULL then NULL is returned.
*
* Example usage:
* @verbatim
*
* // The buffer used to hold the software timer's data structure.
* static StaticTimer_t xTimerBuffer;
*
* // A variable that will be incremented by the software timer's callback
* // function.
* UBaseType_t uxVariableToIncrement = 0;
*
* // A software timer callback function that increments a variable passed to
* // it when the software timer was created. After the 5th increment the
* // callback function stops the software timer.
* static void prvTimerCallback( TimerHandle_t xExpiredTimer )
* {
* UBaseType_t *puxVariableToIncrement;
* BaseType_t xReturned;
*
* // Obtain the address of the variable to increment from the timer ID.
* puxVariableToIncrement = ( UBaseType_t * ) pvTimerGetTimerID( xExpiredTimer );
*
* // Increment the variable to show the timer callback has executed.
* ( *puxVariableToIncrement )++;
*
* // If this callback has executed the required number of times, stop the
* // timer.
* if( *puxVariableToIncrement == 5 )
* {
* // This is called from a timer callback so must not block.
* xTimerStop( xExpiredTimer, staticDONT_BLOCK );
* }
* }
*
*
* void main( void )
* {
* // Create the software time. xTimerCreateStatic() has an extra parameter
* // than the normal xTimerCreate() API function. The parameter is a pointer
* // to the StaticTimer_t structure that will hold the software timer
* // structure. If the parameter is passed as NULL then the structure will be
* // allocated dynamically, just as if xTimerCreate() had been called.
* xTimer = xTimerCreateStatic( "T1", // Text name for the task. Helps debugging only. Not used by FreeRTOS.
* xTimerPeriod, // The period of the timer in ticks.
* pdTRUE, // This is an auto-reload timer.
* ( void * ) &uxVariableToIncrement, // A variable incremented by the software timer's callback function
* prvTimerCallback, // The function to execute when the timer expires.
* &xTimerBuffer ); // The buffer that will hold the software timer structure.
*
* // The scheduler has not started yet so a block time is not used.
* xReturned = xTimerStart( xTimer, 0 );
*
* // ...
* // Create tasks here.
* // ...
*
* // Starting the scheduler will start the timers running as they have already
* // been set into the active state.
* vTaskStartScheduler();
*
* // Should not reach here.
* for( ;; );
* }
* @endverbatim
*/
#if ( configSUPPORT_STATIC_ALLOCATION == 1 )
TimerHandle_t xTimerCreateStatic( const char * const pcTimerName, /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
const TickType_t xTimerPeriodInTicks,
const UBaseType_t uxAutoReload,
void * const pvTimerID,
TimerCallbackFunction_t pxCallbackFunction,
StaticTimer_t * pxTimerBuffer ) PRIVILEGED_FUNCTION;
#endif /* configSUPPORT_STATIC_ALLOCATION */
/**
* void *pvTimerGetTimerID( TimerHandle_t xTimer );
*
* Returns the ID assigned to the timer.
*
* IDs are assigned to timers using the pvTimerID parameter of the call to
* xTimerCreated() that was used to create the timer, and by calling the
* vTimerSetTimerID() API function.
*
* If the same callback function is assigned to multiple timers then the timer
* ID can be used as time specific (timer local) storage.
*
* @param xTimer The timer being queried.
*
* @return The ID assigned to the timer being queried.
*
* Example usage:
*
* See the xTimerCreate() API function example usage scenario.
*/
void * pvTimerGetTimerID( const TimerHandle_t xTimer ) PRIVILEGED_FUNCTION;
/**
* void vTimerSetTimerID( TimerHandle_t xTimer, void *pvNewID );
*
* Sets the ID assigned to the timer.
*
* IDs are assigned to timers using the pvTimerID parameter of the call to
* xTimerCreated() that was used to create the timer.
*
* If the same callback function is assigned to multiple timers then the timer
* ID can be used as time specific (timer local) storage.
*
* @param xTimer The timer being updated.
*
* @param pvNewID The ID to assign to the timer.
*
* Example usage:
*
* See the xTimerCreate() API function example usage scenario.
*/
void vTimerSetTimerID( TimerHandle_t xTimer,
void * pvNewID ) PRIVILEGED_FUNCTION;
/**
* BaseType_t xTimerIsTimerActive( TimerHandle_t xTimer );
*
* Queries a timer to see if it is active or dormant.
*
* A timer will be dormant if:
* 1) It has been created but not started, or
* 2) It is an expired one-shot timer that has not been restarted.
*
* Timers are created in the dormant state. The xTimerStart(), xTimerReset(),
* xTimerStartFromISR(), xTimerResetFromISR(), xTimerChangePeriod() and
* xTimerChangePeriodFromISR() API functions can all be used to transition a timer into the
* active state.
*
* @param xTimer The timer being queried.
*
* @return pdFALSE will be returned if the timer is dormant. A value other than
* pdFALSE will be returned if the timer is active.
*
* Example usage:
* @verbatim
* // This function assumes xTimer has already been created.
* void vAFunction( TimerHandle_t xTimer )
* {
* if( xTimerIsTimerActive( xTimer ) != pdFALSE ) // or more simply and equivalently "if( xTimerIsTimerActive( xTimer ) )"
* {
* // xTimer is active, do something.
* }
* else
* {
* // xTimer is not active, do something else.
* }
* }
* @endverbatim
*/
BaseType_t xTimerIsTimerActive( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION;
/**
* TaskHandle_t xTimerGetTimerDaemonTaskHandle( void );
*
* Simply returns the handle of the timer service/daemon task. It it not valid
* to call xTimerGetTimerDaemonTaskHandle() before the scheduler has been started.
*/
TaskHandle_t xTimerGetTimerDaemonTaskHandle( void ) PRIVILEGED_FUNCTION;
/**
* BaseType_t xTimerStart( TimerHandle_t xTimer, TickType_t xTicksToWait );
*
* Timer functionality is provided by a timer service/daemon task. Many of the
* public FreeRTOS timer API functions send commands to the timer service task
* through a queue called the timer command queue. The timer command queue is
* private to the kernel itself and is not directly accessible to application
* code. The length of the timer command queue is set by the
* configTIMER_QUEUE_LENGTH configuration constant.
*
* xTimerStart() starts a timer that was previously created using the
* xTimerCreate() API function. If the timer had already been started and was
* already in the active state, then xTimerStart() has equivalent functionality
* to the xTimerReset() API function.
*
* Starting a timer ensures the timer is in the active state. If the timer
* is not stopped, deleted, or reset in the mean time, the callback function
* associated with the timer will get called 'n' ticks after xTimerStart() was
* called, where 'n' is the timers defined period.
*
* It is valid to call xTimerStart() before the scheduler has been started, but
* when this is done the timer will not actually start until the scheduler is
* started, and the timers expiry time will be relative to when the scheduler is
* started, not relative to when xTimerStart() was called.
*
* The configUSE_TIMERS configuration constant must be set to 1 for xTimerStart()
* to be available.
*
* @param xTimer The handle of the timer being started/restarted.
*
* @param xTicksToWait Specifies the time, in ticks, that the calling task should
* be held in the Blocked state to wait for the start command to be successfully
* sent to the timer command queue, should the queue already be full when
* xTimerStart() was called. xTicksToWait is ignored if xTimerStart() is called
* before the scheduler is started.
*
* @return pdFAIL will be returned if the start command could not be sent to
* the timer command queue even after xTicksToWait ticks had passed. pdPASS will
* be returned if the command was successfully sent to the timer command queue.
* When the command is actually processed will depend on the priority of the
* timer service/daemon task relative to other tasks in the system, although the
* timers expiry time is relative to when xTimerStart() is actually called. The
* timer service/daemon task priority is set by the configTIMER_TASK_PRIORITY
* configuration constant.
*
* Example usage:
*
* See the xTimerCreate() API function example usage scenario.
*
*/
#define xTimerStart( xTimer, xTicksToWait ) \
xTimerGenericCommand( ( xTimer ), tmrCOMMAND_START, ( xTaskGetTickCount() ), NULL, ( xTicksToWait ) )
/**
* BaseType_t xTimerStop( TimerHandle_t xTimer, TickType_t xTicksToWait );
*
* Timer functionality is provided by a timer service/daemon task. Many of the
* public FreeRTOS timer API functions send commands to the timer service task
* through a queue called the timer command queue. The timer command queue is
* private to the kernel itself and is not directly accessible to application
* code. The length of the timer command queue is set by the
* configTIMER_QUEUE_LENGTH configuration constant.
*
* xTimerStop() stops a timer that was previously started using either of the
* The xTimerStart(), xTimerReset(), xTimerStartFromISR(), xTimerResetFromISR(),
* xTimerChangePeriod() or xTimerChangePeriodFromISR() API functions.
*
* Stopping a timer ensures the timer is not in the active state.
*
* The configUSE_TIMERS configuration constant must be set to 1 for xTimerStop()
* to be available.
*
* @param xTimer The handle of the timer being stopped.
*
* @param xTicksToWait Specifies the time, in ticks, that the calling task should
* be held in the Blocked state to wait for the stop command to be successfully
* sent to the timer command queue, should the queue already be full when
* xTimerStop() was called. xTicksToWait is ignored if xTimerStop() is called
* before the scheduler is started.
*
* @return pdFAIL will be returned if the stop command could not be sent to
* the timer command queue even after xTicksToWait ticks had passed. pdPASS will
* be returned if the command was successfully sent to the timer command queue.
* When the command is actually processed will depend on the priority of the
* timer service/daemon task relative to other tasks in the system. The timer
* service/daemon task priority is set by the configTIMER_TASK_PRIORITY
* configuration constant.
*
* Example usage:
*
* See the xTimerCreate() API function example usage scenario.
*
*/
#define xTimerStop( xTimer, xTicksToWait ) \
xTimerGenericCommand( ( xTimer ), tmrCOMMAND_STOP, 0U, NULL, ( xTicksToWait ) )
/**
* BaseType_t xTimerChangePeriod( TimerHandle_t xTimer,
* TickType_t xNewPeriod,
* TickType_t xTicksToWait );
*
* Timer functionality is provided by a timer service/daemon task. Many of the
* public FreeRTOS timer API functions send commands to the timer service task
* through a queue called the timer command queue. The timer command queue is
* private to the kernel itself and is not directly accessible to application
* code. The length of the timer command queue is set by the
* configTIMER_QUEUE_LENGTH configuration constant.
*
* xTimerChangePeriod() changes the period of a timer that was previously
* created using the xTimerCreate() API function.
*
* xTimerChangePeriod() can be called to change the period of an active or
* dormant state timer.
*
* The configUSE_TIMERS configuration constant must be set to 1 for
* xTimerChangePeriod() to be available.
*
* @param xTimer The handle of the timer that is having its period changed.
*
* @param xNewPeriod The new period for xTimer. Timer periods are specified in
* tick periods, so the constant portTICK_PERIOD_MS can be used to convert a time
* that has been specified in milliseconds. For example, if the timer must
* expire after 100 ticks, then xNewPeriod should be set to 100. Alternatively,
* if the timer must expire after 500ms, then xNewPeriod can be set to
* ( 500 / portTICK_PERIOD_MS ) provided configTICK_RATE_HZ is less than
* or equal to 1000.
*
* @param xTicksToWait Specifies the time, in ticks, that the calling task should
* be held in the Blocked state to wait for the change period command to be
* successfully sent to the timer command queue, should the queue already be
* full when xTimerChangePeriod() was called. xTicksToWait is ignored if
* xTimerChangePeriod() is called before the scheduler is started.
*
* @return pdFAIL will be returned if the change period command could not be
* sent to the timer command queue even after xTicksToWait ticks had passed.
* pdPASS will be returned if the command was successfully sent to the timer
* command queue. When the command is actually processed will depend on the
* priority of the timer service/daemon task relative to other tasks in the
* system. The timer service/daemon task priority is set by the
* configTIMER_TASK_PRIORITY configuration constant.
*
* Example usage:
* @verbatim
* // This function assumes xTimer has already been created. If the timer
* // referenced by xTimer is already active when it is called, then the timer
* // is deleted. If the timer referenced by xTimer is not active when it is
* // called, then the period of the timer is set to 500ms and the timer is
* // started.
* void vAFunction( TimerHandle_t xTimer )
* {
* if( xTimerIsTimerActive( xTimer ) != pdFALSE ) // or more simply and equivalently "if( xTimerIsTimerActive( xTimer ) )"
* {
* // xTimer is already active - delete it.
* xTimerDelete( xTimer );
* }
* else
* {
* // xTimer is not active, change its period to 500ms. This will also
* // cause the timer to start. Block for a maximum of 100 ticks if the
* // change period command cannot immediately be sent to the timer
* // command queue.
* if( xTimerChangePeriod( xTimer, 500 / portTICK_PERIOD_MS, 100 ) == pdPASS )
* {
* // The command was successfully sent.
* }
* else
* {
* // The command could not be sent, even after waiting for 100 ticks
* // to pass. Take appropriate action here.
* }
* }
* }
* @endverbatim
*/
#define xTimerChangePeriod( xTimer, xNewPeriod, xTicksToWait ) \
xTimerGenericCommand( ( xTimer ), tmrCOMMAND_CHANGE_PERIOD, ( xNewPeriod ), NULL, ( xTicksToWait ) )
/**
* BaseType_t xTimerDelete( TimerHandle_t xTimer, TickType_t xTicksToWait );
*
* Timer functionality is provided by a timer service/daemon task. Many of the
* public FreeRTOS timer API functions send commands to the timer service task
* through a queue called the timer command queue. The timer command queue is
* private to the kernel itself and is not directly accessible to application
* code. The length of the timer command queue is set by the
* configTIMER_QUEUE_LENGTH configuration constant.
*
* xTimerDelete() deletes a timer that was previously created using the
* xTimerCreate() API function.
*
* The configUSE_TIMERS configuration constant must be set to 1 for
* xTimerDelete() to be available.
*
* @param xTimer The handle of the timer being deleted.
*
* @param xTicksToWait 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 xTimerDelete() was called. xTicksToWait is ignored if xTimerDelete()
* is called before the scheduler is started.
*
* @return pdFAIL will be returned if the delete command could not be sent to
* the timer command queue even after xTicksToWait ticks had passed. pdPASS will
* be returned if the command was successfully sent to the timer command queue.
* When the command is actually processed will depend on the priority of the
* timer service/daemon task relative to other tasks in the system. The timer
* service/daemon task priority is set by the configTIMER_TASK_PRIORITY
* configuration constant.
*
* Example usage:
*
* See the xTimerChangePeriod() API function example usage scenario.
*/
#define xTimerDelete( xTimer, xTicksToWait ) \
xTimerGenericCommand( ( xTimer ), tmrCOMMAND_DELETE, 0U, NULL, ( xTicksToWait ) )
/**
* BaseType_t xTimerReset( TimerHandle_t xTimer, TickType_t xTicksToWait );
*
* Timer functionality is provided by a timer service/daemon task. Many of the
* public FreeRTOS timer API functions send commands to the timer service task
* through a queue called the timer command queue. The timer command queue is
* private to the kernel itself and is not directly accessible to application
* code. The length of the timer command queue is set by the
* configTIMER_QUEUE_LENGTH configuration constant.
*
* xTimerReset() re-starts a timer that was previously created using the
* xTimerCreate() API function. If the timer had already been started and was
* already in the active state, then xTimerReset() will cause the timer to
* re-evaluate its expiry time so that it is relative to when xTimerReset() was
* called. If the timer was in the dormant state then xTimerReset() has
* equivalent functionality to the xTimerStart() API function.
*
* Resetting a timer ensures the timer is in the active state. If the timer
* is not stopped, deleted, or reset in the mean time, the callback function
* associated with the timer will get called 'n' ticks after xTimerReset() was
* called, where 'n' is the timers defined period.
*
* It is valid to call xTimerReset() before the scheduler has been started, but
* when this is done the timer will not actually start until the scheduler is
* started, and the timers expiry time will be relative to when the scheduler is
* started, not relative to when xTimerReset() was called.
*
* The configUSE_TIMERS configuration constant must be set to 1 for xTimerReset()
* to be available.
*
* @param xTimer The handle of the timer being reset/started/restarted.
*
* @param xTicksToWait Specifies the time, in ticks, that the calling task should
* be held in the Blocked state to wait for the reset command to be successfully
* sent to the timer command queue, should the queue already be full when
* xTimerReset() was called. xTicksToWait is ignored if xTimerReset() is called
* before the scheduler is started.
*
* @return pdFAIL will be returned if the reset command could not be sent to
* the timer command queue even after xTicksToWait ticks had passed. pdPASS will
* be returned if the command was successfully sent to the timer command queue.
* When the command is actually processed will depend on the priority of the
* timer service/daemon task relative to other tasks in the system, although the
* timers expiry time is relative to when xTimerStart() is actually called. The
* timer service/daemon task priority is set by the configTIMER_TASK_PRIORITY
* configuration constant.
*
* Example usage:
* @verbatim
* // When a key is pressed, an LCD back-light is switched on. If 5 seconds pass
* // without a key being pressed, then the LCD back-light is switched off. In
* // this case, the timer is a one-shot timer.
*
* TimerHandle_t xBacklightTimer = NULL;
*
* // The callback function assigned to the one-shot timer. In this case the
* // parameter is not used.
* void vBacklightTimerCallback( TimerHandle_t pxTimer )
* {
* // The timer expired, therefore 5 seconds must have passed since a key
* // was pressed. Switch off the LCD back-light.
* vSetBacklightState( BACKLIGHT_OFF );
* }
*
* // The key press event handler.
* void vKeyPressEventHandler( char cKey )
* {
* // Ensure the LCD back-light is on, then reset the timer that is
* // responsible for turning the back-light off after 5 seconds of
* // key inactivity. Wait 10 ticks for the command to be successfully sent
* // if it cannot be sent immediately.
* vSetBacklightState( BACKLIGHT_ON );
* if( xTimerReset( xBacklightTimer, 100 ) != pdPASS )
* {
* // The reset command was not executed successfully. Take appropriate
* // action here.
* }
*
* // Perform the rest of the key processing here.
* }
*
* void main( void )
* {
* int32_t x;
*
* // Create then start the one-shot timer that is responsible for turning
* // the back-light off if no keys are pressed within a 5 second period.
* xBacklightTimer = xTimerCreate( "BacklightTimer", // Just a text name, not used by the kernel.
* ( 5000 / portTICK_PERIOD_MS), // The timer period in ticks.
* pdFALSE, // The timer is a one-shot timer.
* 0, // The id is not used by the callback so can take any value.
* vBacklightTimerCallback // The callback function that switches the LCD back-light off.
* );
*
* if( xBacklightTimer == NULL )
* {
* // The timer was not created.
* }
* else
* {
* // Start the timer. No block time is specified, and even if one was
* // it would be ignored because the scheduler has not yet been
* // started.
* if( xTimerStart( xBacklightTimer, 0 ) != pdPASS )
* {
* // The timer could not be set into the Active state.
* }
* }
*
* // ...
* // Create tasks here.
* // ...
*
* // Starting the scheduler will start the timer running as it has already
* // been set into the active state.
* vTaskStartScheduler();
*
* // Should not reach here.
* for( ;; );
* }
* @endverbatim
*/
#define xTimerReset( xTimer, xTicksToWait ) \
xTimerGenericCommand( ( xTimer ), tmrCOMMAND_RESET, ( xTaskGetTickCount() ), NULL, ( xTicksToWait ) )
/**
* BaseType_t xTimerStartFromISR( TimerHandle_t xTimer,
* BaseType_t *pxHigherPriorityTaskWoken );
*
* A version of xTimerStart() that can be called from an interrupt service
* routine.
*
* @param xTimer The handle of the timer being started/restarted.
*
* @param pxHigherPriorityTaskWoken The timer service/daemon task spends most
* of its time in the Blocked state, waiting for messages to arrive on the timer
* command queue. Calling xTimerStartFromISR() writes a message to the timer
* command queue, so has the potential to transition the timer service/daemon
* task out of the Blocked state. If calling xTimerStartFromISR() causes the
* timer service/daemon task to leave the Blocked state, and the timer service/
* daemon task has a priority equal to or greater than the currently executing
* task (the task that was interrupted), then *pxHigherPriorityTaskWoken will
* get set to pdTRUE internally within the xTimerStartFromISR() function. If
* xTimerStartFromISR() sets this value to pdTRUE then a context switch should
* be performed before the interrupt exits.
*
* @return pdFAIL will be returned if the start command could not be sent to
* the timer command queue. pdPASS will be returned if the command was
* successfully sent to the timer command queue. When the command is actually
* processed will depend on the priority of the timer service/daemon task
* relative to other tasks in the system, although the timers expiry time is
* relative to when xTimerStartFromISR() is actually called. The timer
* service/daemon task priority is set by the configTIMER_TASK_PRIORITY
* configuration constant.
*
* Example usage:
* @verbatim
* // This scenario assumes xBacklightTimer has already been created. When a
* // key is pressed, an LCD back-light is switched on. If 5 seconds pass
* // without a key being pressed, then the LCD back-light is switched off. In
* // this case, the timer is a one-shot timer, and unlike the example given for
* // the xTimerReset() function, the key press event handler is an interrupt
* // service routine.
*
* // The callback function assigned to the one-shot timer. In this case the
* // parameter is not used.
* void vBacklightTimerCallback( TimerHandle_t pxTimer )
* {
* // The timer expired, therefore 5 seconds must have passed since a key
* // was pressed. Switch off the LCD back-light.
* vSetBacklightState( BACKLIGHT_OFF );
* }
*
* // The key press interrupt service routine.
* void vKeyPressEventInterruptHandler( void )
* {
* BaseType_t xHigherPriorityTaskWoken = pdFALSE;
*
* // Ensure the LCD back-light is on, then restart the timer that is
* // responsible for turning the back-light off after 5 seconds of
* // key inactivity. This is an interrupt service routine so can only
* // call FreeRTOS API functions that end in "FromISR".
* vSetBacklightState( BACKLIGHT_ON );
*
* // xTimerStartFromISR() or xTimerResetFromISR() could be called here
* // as both cause the timer to re-calculate its expiry time.
* // xHigherPriorityTaskWoken was initialised to pdFALSE when it was
* // declared (in this function).
* if( xTimerStartFromISR( xBacklightTimer, &xHigherPriorityTaskWoken ) != pdPASS )
* {
* // The start command was not executed successfully. Take appropriate
* // action here.
* }
*
* // Perform the rest of the key processing here.
*
* // If xHigherPriorityTaskWoken equals pdTRUE, then a context switch
* // should be performed. The syntax required to perform a context switch
* // from inside an ISR varies from port to port, and from compiler to
* // compiler. Inspect the demos for the port you are using to find the
* // actual syntax required.
* if( xHigherPriorityTaskWoken != pdFALSE )
* {
* // Call the interrupt safe yield function here (actual function
* // depends on the FreeRTOS port being used).
* }
* }
* @endverbatim
*/
#define xTimerStartFromISR( xTimer, pxHigherPriorityTaskWoken ) \
xTimerGenericCommand( ( xTimer ), tmrCOMMAND_START_FROM_ISR, ( xTaskGetTickCountFromISR() ), ( pxHigherPriorityTaskWoken ), 0U )
/**
* BaseType_t xTimerStopFromISR( TimerHandle_t xTimer,
* BaseType_t *pxHigherPriorityTaskWoken );
*
* A version of xTimerStop() that can be called from an interrupt service
* routine.
*
* @param xTimer The handle of the timer being stopped.
*
* @param pxHigherPriorityTaskWoken The timer service/daemon task spends most
* of its time in the Blocked state, waiting for messages to arrive on the timer
* command queue. Calling xTimerStopFromISR() writes a message to the timer
* command queue, so has the potential to transition the timer service/daemon
* task out of the Blocked state. If calling xTimerStopFromISR() causes the
* timer service/daemon task to leave the Blocked state, and the timer service/
* daemon task has a priority equal to or greater than the currently executing
* task (the task that was interrupted), then *pxHigherPriorityTaskWoken will
* get set to pdTRUE internally within the xTimerStopFromISR() function. If
* xTimerStopFromISR() sets this value to pdTRUE then a context switch should
* be performed before the interrupt exits.
*
* @return pdFAIL will be returned if the stop command could not be sent to
* the timer command queue. pdPASS will be returned if the command was
* successfully sent to the timer command queue. When the command is actually
* processed will depend on the priority of the timer service/daemon task
* relative to other tasks in the system. The timer service/daemon task
* priority is set by the configTIMER_TASK_PRIORITY configuration constant.
*
* Example usage:
* @verbatim
* // This scenario assumes xTimer has already been created and started. When
* // an interrupt occurs, the timer should be simply stopped.
*
* // The interrupt service routine that stops the timer.
* void vAnExampleInterruptServiceRoutine( void )
* {
* BaseType_t xHigherPriorityTaskWoken = pdFALSE;
*
* // The interrupt has occurred - simply stop the timer.
* // xHigherPriorityTaskWoken was set to pdFALSE where it was defined
* // (within this function). As this is an interrupt service routine, only
* // FreeRTOS API functions that end in "FromISR" can be used.
* if( xTimerStopFromISR( xTimer, &xHigherPriorityTaskWoken ) != pdPASS )
* {
* // The stop command was not executed successfully. Take appropriate
* // action here.
* }
*
* // If xHigherPriorityTaskWoken equals pdTRUE, then a context switch
* // should be performed. The syntax required to perform a context switch
* // from inside an ISR varies from port to port, and from compiler to
* // compiler. Inspect the demos for the port you are using to find the
* // actual syntax required.
* if( xHigherPriorityTaskWoken != pdFALSE )
* {
* // Call the interrupt safe yield function here (actual function
* // depends on the FreeRTOS port being used).
* }
* }
* @endverbatim
*/
#define xTimerStopFromISR( xTimer, pxHigherPriorityTaskWoken ) \
xTimerGenericCommand( ( xTimer ), tmrCOMMAND_STOP_FROM_ISR, 0, ( pxHigherPriorityTaskWoken ), 0U )
/**
* BaseType_t xTimerChangePeriodFromISR( TimerHandle_t xTimer,
* TickType_t xNewPeriod,
* BaseType_t *pxHigherPriorityTaskWoken );
*
* A version of xTimerChangePeriod() that can be called from an interrupt
* service routine.
*
* @param xTimer The handle of the timer that is having its period changed.
*
* @param xNewPeriod The new period for xTimer. Timer periods are specified in
* tick periods, so the constant portTICK_PERIOD_MS can be used to convert a time
* that has been specified in milliseconds. For example, if the timer must
* expire after 100 ticks, then xNewPeriod should be set to 100. Alternatively,
* if the timer must expire after 500ms, then xNewPeriod can be set to
* ( 500 / portTICK_PERIOD_MS ) provided configTICK_RATE_HZ is less than
* or equal to 1000.
*
* @param pxHigherPriorityTaskWoken The timer service/daemon task spends most
* of its time in the Blocked state, waiting for messages to arrive on the timer
* command queue. Calling xTimerChangePeriodFromISR() writes a message to the
* timer command queue, so has the potential to transition the timer service/
* daemon task out of the Blocked state. If calling xTimerChangePeriodFromISR()
* causes the timer service/daemon task to leave the Blocked state, and the
* timer service/daemon task has a priority equal to or greater than the
* currently executing task (the task that was interrupted), then
* *pxHigherPriorityTaskWoken will get set to pdTRUE internally within the
* xTimerChangePeriodFromISR() function. If xTimerChangePeriodFromISR() sets
* this value to pdTRUE then a context switch should be performed before the
* interrupt exits.
*
* @return pdFAIL will be returned if the command to change the timers period
* could not be sent to the timer command queue. pdPASS will be returned if the
* command was successfully sent to the timer command queue. When the command
* is actually processed will depend on the priority of the timer service/daemon
* task relative to other tasks in the system. The timer service/daemon task
* priority is set by the configTIMER_TASK_PRIORITY configuration constant.
*
* Example usage:
* @verbatim
* // This scenario assumes xTimer has already been created and started. When
* // an interrupt occurs, the period of xTimer should be changed to 500ms.
*
* // The interrupt service routine that changes the period of xTimer.
* void vAnExampleInterruptServiceRoutine( void )
* {
* BaseType_t xHigherPriorityTaskWoken = pdFALSE;
*
* // The interrupt has occurred - change the period of xTimer to 500ms.
* // xHigherPriorityTaskWoken was set to pdFALSE where it was defined
* // (within this function). As this is an interrupt service routine, only
* // FreeRTOS API functions that end in "FromISR" can be used.
* if( xTimerChangePeriodFromISR( xTimer, &xHigherPriorityTaskWoken ) != pdPASS )
* {
* // The command to change the timers period was not executed
* // successfully. Take appropriate action here.
* }
*
* // If xHigherPriorityTaskWoken equals pdTRUE, then a context switch
* // should be performed. The syntax required to perform a context switch
* // from inside an ISR varies from port to port, and from compiler to
* // compiler. Inspect the demos for the port you are using to find the
* // actual syntax required.
* if( xHigherPriorityTaskWoken != pdFALSE )
* {
* // Call the interrupt safe yield function here (actual function
* // depends on the FreeRTOS port being used).
* }
* }
* @endverbatim
*/
#define xTimerChangePeriodFromISR( xTimer, xNewPeriod, pxHigherPriorityTaskWoken ) \
xTimerGenericCommand( ( xTimer ), tmrCOMMAND_CHANGE_PERIOD_FROM_ISR, ( xNewPeriod ), ( pxHigherPriorityTaskWoken ), 0U )
/**
* BaseType_t xTimerResetFromISR( TimerHandle_t xTimer,
* BaseType_t *pxHigherPriorityTaskWoken );
*
* A version of xTimerReset() that can be called from an interrupt service
* routine.
*
* @param xTimer The handle of the timer that is to be started, reset, or
* restarted.
*
* @param pxHigherPriorityTaskWoken The timer service/daemon task spends most
* of its time in the Blocked state, waiting for messages to arrive on the timer
* command queue. Calling xTimerResetFromISR() writes a message to the timer
* command queue, so has the potential to transition the timer service/daemon
* task out of the Blocked state. If calling xTimerResetFromISR() causes the
* timer service/daemon task to leave the Blocked state, and the timer service/
* daemon task has a priority equal to or greater than the currently executing
* task (the task that was interrupted), then *pxHigherPriorityTaskWoken will
* get set to pdTRUE internally within the xTimerResetFromISR() function. If
* xTimerResetFromISR() sets this value to pdTRUE then a context switch should
* be performed before the interrupt exits.
*
* @return pdFAIL will be returned if the reset command could not be sent to
* the timer command queue. pdPASS will be returned if the command was
* successfully sent to the timer command queue. When the command is actually
* processed will depend on the priority of the timer service/daemon task
* relative to other tasks in the system, although the timers expiry time is
* relative to when xTimerResetFromISR() is actually called. The timer service/daemon
* task priority is set by the configTIMER_TASK_PRIORITY configuration constant.
*
* Example usage:
* @verbatim
* // This scenario assumes xBacklightTimer has already been created. When a
* // key is pressed, an LCD back-light is switched on. If 5 seconds pass
* // without a key being pressed, then the LCD back-light is switched off. In
* // this case, the timer is a one-shot timer, and unlike the example given for
* // the xTimerReset() function, the key press event handler is an interrupt
* // service routine.
*
* // The callback function assigned to the one-shot timer. In this case the
* // parameter is not used.
* void vBacklightTimerCallback( TimerHandle_t pxTimer )
* {
* // The timer expired, therefore 5 seconds must have passed since a key
* // was pressed. Switch off the LCD back-light.
* vSetBacklightState( BACKLIGHT_OFF );
* }
*
* // The key press interrupt service routine.
* void vKeyPressEventInterruptHandler( void )
* {
* BaseType_t xHigherPriorityTaskWoken = pdFALSE;
*
* // Ensure the LCD back-light is on, then reset the timer that is
* // responsible for turning the back-light off after 5 seconds of
* // key inactivity. This is an interrupt service routine so can only
* // call FreeRTOS API functions that end in "FromISR".
* vSetBacklightState( BACKLIGHT_ON );
*
* // xTimerStartFromISR() or xTimerResetFromISR() could be called here
* // as both cause the timer to re-calculate its expiry time.
* // xHigherPriorityTaskWoken was initialised to pdFALSE when it was
* // declared (in this function).
* if( xTimerResetFromISR( xBacklightTimer, &xHigherPriorityTaskWoken ) != pdPASS )
* {
* // The reset command was not executed successfully. Take appropriate
* // action here.
* }
*
* // Perform the rest of the key processing here.
*
* // If xHigherPriorityTaskWoken equals pdTRUE, then a context switch
* // should be performed. The syntax required to perform a context switch
* // from inside an ISR varies from port to port, and from compiler to
* // compiler. Inspect the demos for the port you are using to find the
* // actual syntax required.
* if( xHigherPriorityTaskWoken != pdFALSE )
* {
* // Call the interrupt safe yield function here (actual function
* // depends on the FreeRTOS port being used).
* }
* }
* @endverbatim
*/
#define xTimerResetFromISR( xTimer, pxHigherPriorityTaskWoken ) \
xTimerGenericCommand( ( xTimer ), tmrCOMMAND_RESET_FROM_ISR, ( xTaskGetTickCountFromISR() ), ( pxHigherPriorityTaskWoken ), 0U )
/**
* BaseType_t xTimerPendFunctionCallFromISR( PendedFunction_t xFunctionToPend,
* void *pvParameter1,
* uint32_t ulParameter2,
* BaseType_t *pxHigherPriorityTaskWoken );
*
*
* Used from application interrupt service routines to defer the execution of a
* function to the RTOS daemon task (the timer service task, hence this function
* is implemented in timers.c and is prefixed with 'Timer').
*
* Ideally an interrupt service routine (ISR) is kept as short as possible, but
* sometimes an ISR either has a lot of processing to do, or needs to perform
* processing that is not deterministic. In these cases
* xTimerPendFunctionCallFromISR() can be used to defer processing of a function
* to the RTOS daemon task.
*
* A mechanism is provided that allows the interrupt to return directly to the
* task that will subsequently execute the pended callback function. This
* allows the callback function to execute contiguously in time with the
* interrupt - just as if the callback had executed in the interrupt itself.
*
* @param xFunctionToPend The function to execute from the timer service/
* daemon task. The function must conform to the PendedFunction_t
* prototype.
*
* @param pvParameter1 The value of the callback function's first parameter.
* The parameter has a void * type to allow it to be used to pass any type.
* For example, unsigned longs can be cast to a void *, or the void * can be
* used to point to a structure.
*
* @param ulParameter2 The value of the callback function's second parameter.
*
* @param pxHigherPriorityTaskWoken As mentioned above, calling this function
* will result in a message being sent to the timer daemon task. If the
* priority of the timer daemon task (which is set using
* configTIMER_TASK_PRIORITY in FreeRTOSConfig.h) is higher than the priority of
* the currently running task (the task the interrupt interrupted) then
* *pxHigherPriorityTaskWoken will be set to pdTRUE within
* xTimerPendFunctionCallFromISR(), indicating that a context switch should be
* requested before the interrupt exits. For that reason
* *pxHigherPriorityTaskWoken must be initialised to pdFALSE. See the
* example code below.
*
* @return pdPASS is returned if the message was successfully sent to the
* timer daemon task, otherwise pdFALSE is returned.
*
* Example usage:
* @verbatim
*
* // The callback function that will execute in the context of the daemon task.
* // Note callback functions must all use this same prototype.
* void vProcessInterface( void *pvParameter1, uint32_t ulParameter2 )
* {
* BaseType_t xInterfaceToService;
*
* // The interface that requires servicing is passed in the second
* // parameter. The first parameter is not used in this case.
* xInterfaceToService = ( BaseType_t ) ulParameter2;
*
* // ...Perform the processing here...
* }
*
* // An ISR that receives data packets from multiple interfaces
* void vAnISR( void )
* {
* BaseType_t xInterfaceToService, xHigherPriorityTaskWoken;
*
* // Query the hardware to determine which interface needs processing.
* xInterfaceToService = prvCheckInterfaces();
*
* // The actual processing is to be deferred to a task. Request the
* // vProcessInterface() callback function is executed, passing in the
* // number of the interface that needs processing. The interface to
* // service is passed in the second parameter. The first parameter is
* // not used in this case.
* xHigherPriorityTaskWoken = pdFALSE;
* xTimerPendFunctionCallFromISR( vProcessInterface, NULL, ( uint32_t ) xInterfaceToService, &xHigherPriorityTaskWoken );
*
* // If xHigherPriorityTaskWoken is now set to pdTRUE then a context
* // switch should be requested. The macro used is port specific and will
* // be either portYIELD_FROM_ISR() or portEND_SWITCHING_ISR() - refer to
* // the documentation page for the port being used.
* portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
*
* }
* @endverbatim
*/
BaseType_t xTimerPendFunctionCallFromISR( PendedFunction_t xFunctionToPend,
void * pvParameter1,
uint32_t ulParameter2,
BaseType_t * pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION;
/**
* BaseType_t xTimerPendFunctionCall( PendedFunction_t xFunctionToPend,
* void *pvParameter1,
* uint32_t ulParameter2,
* TickType_t xTicksToWait );
*
*
* Used to defer the execution of a function to the RTOS daemon task (the timer
* service task, hence this function is implemented in timers.c and is prefixed
* with 'Timer').
*
* @param xFunctionToPend The function to execute from the timer service/
* daemon task. The function must conform to the PendedFunction_t
* prototype.
*
* @param pvParameter1 The value of the callback function's first parameter.
* The parameter has a void * type to allow it to be used to pass any type.
* For example, unsigned longs can be cast to a void *, or the void * can be
* used to point to a structure.
*
* @param ulParameter2 The value of the callback function's second parameter.
*
* @param xTicksToWait Calling this function will result in a message being
* sent to the timer daemon task on a queue. xTicksToWait is the amount of
* time the calling task should remain in the Blocked state (so not using any
* processing time) for space to become available on the timer queue if the
* queue is found to be full.
*
* @return pdPASS is returned if the message was successfully sent to the
* timer daemon task, otherwise pdFALSE is returned.
*
*/
BaseType_t xTimerPendFunctionCall( PendedFunction_t xFunctionToPend,
void * pvParameter1,
uint32_t ulParameter2,
TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
/**
* const char * const pcTimerGetName( TimerHandle_t xTimer );
*
* Returns the name that was assigned to a timer when the timer was created.
*
* @param xTimer The handle of the timer being queried.
*
* @return The name assigned to the timer specified by the xTimer parameter.
*/
const char * pcTimerGetName( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
/**
* void vTimerSetReloadMode( TimerHandle_t xTimer, const UBaseType_t uxAutoReload );
*
* Updates a timer to be either an auto-reload timer, in which case the timer
* automatically resets itself each time it expires, or a one-shot timer, in
* which case the timer will only expire once unless it is manually restarted.
*
* @param xTimer The handle of the timer being updated.
*
* @param uxAutoReload If uxAutoReload is set to pdTRUE then the timer will
* expire repeatedly with a frequency set by the timer's period (see the
* xTimerPeriodInTicks parameter of the xTimerCreate() API function). If
* uxAutoReload is set to pdFALSE then the timer will be a one-shot timer and
* enter the dormant state after it expires.
*/
void vTimerSetReloadMode( TimerHandle_t xTimer,
const UBaseType_t uxAutoReload ) PRIVILEGED_FUNCTION;
/**
* UBaseType_t uxTimerGetReloadMode( TimerHandle_t xTimer );
*
* Queries a timer to determine if it is an auto-reload timer, in which case the timer
* automatically resets itself each time it expires, or a one-shot timer, in
* which case the timer will only expire once unless it is manually restarted.
*
* @param xTimer The handle of the timer being queried.
*
* @return If the timer is an auto-reload timer then pdTRUE is returned, otherwise
* pdFALSE is returned.
*/
UBaseType_t uxTimerGetReloadMode( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION;
/**
* TickType_t xTimerGetPeriod( TimerHandle_t xTimer );
*
* Returns the period of a timer.
*
* @param xTimer The handle of the timer being queried.
*
* @return The period of the timer in ticks.
*/
TickType_t xTimerGetPeriod( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION;
/**
* TickType_t xTimerGetExpiryTime( TimerHandle_t xTimer );
*
* Returns the time in ticks at which the timer will expire. If this is less
* than the current tick count then the expiry time has overflowed from the
* current time.
*
* @param xTimer The handle of the timer being queried.
*
* @return If the timer is running then the time in ticks at which the timer
* will next expire is returned. If the timer is not running then the return
* value is undefined.
*/
TickType_t xTimerGetExpiryTime( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION;
/*
* Functions beyond this part are not part of the public API and are intended
* for use by the kernel only.
*/
BaseType_t xTimerCreateTimerTask( void ) PRIVILEGED_FUNCTION;
BaseType_t xTimerGenericCommand( TimerHandle_t xTimer,
const BaseType_t xCommandID,
const TickType_t xOptionalValue,
BaseType_t * const pxHigherPriorityTaskWoken,
const TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
#if ( configUSE_TRACE_FACILITY == 1 )
void vTimerSetTimerNumber( TimerHandle_t xTimer,
UBaseType_t uxTimerNumber ) PRIVILEGED_FUNCTION;
UBaseType_t uxTimerGetTimerNumber( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION;
#endif
#if ( configSUPPORT_STATIC_ALLOCATION == 1 )
/**
* task.h
* <pre>void vApplicationGetTimerTaskMemory( StaticTask_t ** ppxTimerTaskTCBBuffer, StackType_t ** ppxTimerTaskStackBuffer, uint32_t *pulTimerTaskStackSize ) </pre>
*
* This function is used to provide a statically allocated block of memory to FreeRTOS to hold the Timer Task TCB. This function is required when
* configSUPPORT_STATIC_ALLOCATION is set. For more information see this URI: https://www.FreeRTOS.org/a00110.html#configSUPPORT_STATIC_ALLOCATION
*
* @param ppxTimerTaskTCBBuffer A handle to a statically allocated TCB buffer
* @param ppxTimerTaskStackBuffer A handle to a statically allocated Stack buffer for thie idle task
* @param pulTimerTaskStackSize A pointer to the number of elements that will fit in the allocated stack buffer
*/
void vApplicationGetTimerTaskMemory( StaticTask_t ** ppxTimerTaskTCBBuffer,
StackType_t ** ppxTimerTaskStackBuffer,
uint32_t * pulTimerTaskStackSize );
#endif
/* *INDENT-OFF* */
#ifdef __cplusplus
}
#endif
/* *INDENT-ON* */
#endif /* TIMERS_H */