/* | |
FreeRTOS V7.2.0 - Copyright (C) 2012 Real Time Engineers Ltd. | |
*************************************************************************** | |
* * | |
* FreeRTOS tutorial books are available in pdf and paperback. * | |
* Complete, revised, and edited pdf reference manuals are also * | |
* available. * | |
* * | |
* Purchasing FreeRTOS documentation will not only help you, by * | |
* ensuring you get running as quickly as possible and with an * | |
* in-depth knowledge of how to use FreeRTOS, it will also help * | |
* the FreeRTOS project to continue with its mission of providing * | |
* professional grade, cross platform, de facto standard solutions * | |
* for microcontrollers - completely free of charge! * | |
* * | |
* >>> See http://www.FreeRTOS.org/Documentation for details. <<< * | |
* * | |
* Thank you for using FreeRTOS, and thank you for your support! * | |
* * | |
*************************************************************************** | |
This file is part of the FreeRTOS distribution. | |
FreeRTOS is free software; you can redistribute it and/or modify it under | |
the terms of the GNU General Public License (version 2) as published by the | |
Free Software Foundation AND MODIFIED BY the FreeRTOS exception. | |
>>>NOTE<<< The modification to the GPL is included to allow you to | |
distribute a combined work that includes FreeRTOS without being obliged to | |
provide the source code for proprietary components outside of the FreeRTOS | |
kernel. FreeRTOS is distributed in the hope that it will be useful, but | |
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
more details. You should have received a copy of the GNU General Public | |
License and the FreeRTOS license exception along with FreeRTOS; if not it | |
can be viewed here: http://www.freertos.org/a00114.html and also obtained | |
by writing to Richard Barry, contact details for whom are available on the | |
FreeRTOS WEB site. | |
1 tab == 4 spaces! | |
*************************************************************************** | |
* * | |
* Having a problem? Start by reading the FAQ "My application does * | |
* not run, what could be wrong? * | |
* * | |
* http://www.FreeRTOS.org/FAQHelp.html * | |
* * | |
*************************************************************************** | |
http://www.FreeRTOS.org - Documentation, training, latest information, | |
license and contact details. | |
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products, | |
including FreeRTOS+Trace - an indispensable productivity tool. | |
Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell | |
the code with commercial support, indemnification, and middleware, under | |
the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also | |
provide a safety engineered and independently SIL3 certified version under | |
the SafeRTOS brand: http://www.SafeRTOS.com. | |
*/ | |
#ifndef TIMERS_H | |
#define TIMERS_H | |
#ifndef INC_FREERTOS_H | |
#error "include FreeRTOS.h must appear in source files before include timers.h" | |
#endif | |
#include "portable.h" | |
#include "list.h" | |
#include "task.h" | |
#ifdef __cplusplus | |
extern "C" { | |
#endif | |
/* 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. */ | |
#define tmrCOMMAND_START 0 | |
#define tmrCOMMAND_STOP 1 | |
#define tmrCOMMAND_CHANGE_PERIOD 2 | |
#define tmrCOMMAND_DELETE 3 | |
/*----------------------------------------------------------- | |
* MACROS AND DEFINITIONS | |
*----------------------------------------------------------*/ | |
/** | |
* Type by which software timers are referenced. For example, a call to | |
* xTimerCreate() returns an xTimerHandle variable that can then be used to | |
* reference the subject timer in calls to other software timer API functions | |
* (for example, xTimerStart(), xTimerReset(), etc.). | |
*/ | |
typedef void * xTimerHandle; | |
/* Define the prototype to which timer callback functions must conform. */ | |
typedef void (*tmrTIMER_CALLBACK)( xTimerHandle xTimer ); | |
/** | |
* xTimerHandle xTimerCreate( const signed char *pcTimerName, | |
* portTickType xTimerPeriodInTicks, | |
* unsigned portBASE_TYPE uxAutoReload, | |
* void * pvTimerID, | |
* tmrTIMER_CALLBACK pxCallbackFunction ); | |
* | |
* Creates a new software timer instance. This allocates the storage required | |
* by the new timer, initialises the new timers internal state, and returns a | |
* handle by which the new timer can be referenced. | |
* | |
* 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_RATE_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_RATE_MS ) | |
* provided configTICK_RATE_HZ is less than or equal to 1000. | |
* | |
* @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 tmrTIMER_CALLBACK, | |
* which is "void vCallbackFunction( xTimerHandle xTimer );". | |
* | |
* @return If the timer is successfully create then a handle to the newly | |
* created timer is returned. If the timer cannot be created (because either | |
* there is insufficient FreeRTOS heap remaining to allocate the timer | |
* structures, or the timer period was set to 0) then 0 is returned. | |
* | |
* Example usage: | |
* | |
* #define NUM_TIMERS 5 | |
* | |
* // An array to hold handles to the created timers. | |
* xTimerHandle xTimers[ NUM_TIMERS ]; | |
* | |
* // An array to hold a count of the number of times each timer expires. | |
* long 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( xTimerHandle pxTimer ) | |
* { | |
* long lArrayIndex; | |
* const long xMaxExpiryCountBeforeStopping = 10; | |
* | |
* // Optionally do something if the pxTimer parameter is NULL. | |
* configASSERT( pxTimer ); | |
* | |
* // Which timer expired? | |
* lArrayIndex = ( long ) 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 ) | |
* { | |
* long 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. | |
* xTaskStartScheduler(); | |
* | |
* // Should not reach here. | |
* for( ;; ); | |
* } | |
*/ | |
xTimerHandle xTimerCreate( const signed char *pcTimerName, portTickType xTimerPeriodInTicks, unsigned portBASE_TYPE uxAutoReload, void * pvTimerID, tmrTIMER_CALLBACK pxCallbackFunction ) PRIVILEGED_FUNCTION; | |
/** | |
* void *pvTimerGetTimerID( xTimerHandle 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. | |
* | |
* If the same callback function is assigned to multiple timers then the timer | |
* ID can be used within the callback function to identify which timer actually | |
* expired. | |
* | |
* @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( xTimerHandle xTimer ) PRIVILEGED_FUNCTION; | |
/** | |
* portBASE_TYPE xTimerIsTimerActive( xTimerHandle 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 on-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: | |
* | |
* // This function assumes xTimer has already been created. | |
* void vAFunction( xTimerHandle 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. | |
* } | |
* } | |
*/ | |
portBASE_TYPE xTimerIsTimerActive( xTimerHandle xTimer ) PRIVILEGED_FUNCTION; | |
/** | |
* xTimerGetTimerDaemonTaskHandle() is only available if | |
* INCLUDE_xTimerGetTimerDaemonTaskHandle is set to 1 in FreeRTOSConfig.h. | |
* | |
* Simply returns the handle of the timer service/daemon task. It it not valid | |
* to call xTimerGetTimerDaemonTaskHandle() before the scheduler has been started. | |
*/ | |
xTaskHandle xTimerGetTimerDaemonTaskHandle( void ); | |
/** | |
* portBASE_TYPE xTimerStart( xTimerHandle xTimer, portTickType xBlockTime ); | |
* | |
* 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 | |
* though 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 xBlockTime 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. xBlockTime 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 xBlockTime 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, xBlockTime ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_START, ( xTaskGetTickCount() ), NULL, ( xBlockTime ) ) | |
/** | |
* portBASE_TYPE xTimerStop( xTimerHandle xTimer, portTickType xBlockTime ); | |
* | |
* 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 | |
* though 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 xBlockTime 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. xBlockTime 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 xBlockTime 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, xBlockTime ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_STOP, 0U, NULL, ( xBlockTime ) ) | |
/** | |
* portBASE_TYPE xTimerChangePeriod( xTimerHandle xTimer, | |
* portTickType xNewPeriod, | |
* portTickType xBlockTime ); | |
* | |
* 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 | |
* though 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_RATE_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_RATE_MS ) provided configTICK_RATE_HZ is less than | |
* or equal to 1000. | |
* | |
* @param xBlockTime 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. xBlockTime 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 xBlockTime 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: | |
* | |
* // 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( xTimerHandle 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_RATE_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. | |
* } | |
* } | |
* } | |
*/ | |
#define xTimerChangePeriod( xTimer, xNewPeriod, xBlockTime ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_CHANGE_PERIOD, ( xNewPeriod ), NULL, ( xBlockTime ) ) | |
/** | |
* portBASE_TYPE xTimerDelete( xTimerHandle xTimer, portTickType xBlockTime ); | |
* | |
* 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 | |
* though 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 xBlockTime 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. xBlockTime 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 xBlockTime 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, xBlockTime ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_DELETE, 0U, NULL, ( xBlockTime ) ) | |
/** | |
* portBASE_TYPE xTimerReset( xTimerHandle xTimer, portTickType xBlockTime ); | |
* | |
* 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 | |
* though 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 xBlockTime 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. xBlockTime 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 xBlockTime 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: | |
* | |
* // 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. | |
* | |
* xTimerHandle xBacklightTimer = NULL; | |
* | |
* // The callback function assigned to the one-shot timer. In this case the | |
* // parameter is not used. | |
* void vBacklightTimerCallback( xTimerHandle 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 ) | |
* { | |
* long 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_RATE_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. | |
* xTaskStartScheduler(); | |
* | |
* // Should not reach here. | |
* for( ;; ); | |
* } | |
*/ | |
#define xTimerReset( xTimer, xBlockTime ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_START, ( xTaskGetTickCount() ), NULL, ( xBlockTime ) ) | |
/** | |
* portBASE_TYPE xTimerStartFromISR( xTimerHandle xTimer, | |
* portBASE_TYPE *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: | |
* | |
* // 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( xTimerHandle 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 ) | |
* { | |
* portBASE_TYPE 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. | |
* } | |
* } | |
*/ | |
#define xTimerStartFromISR( xTimer, pxHigherPriorityTaskWoken ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_START, ( xTaskGetTickCountFromISR() ), ( pxHigherPriorityTaskWoken ), 0U ) | |
/** | |
* portBASE_TYPE xTimerStopFromISR( xTimerHandle xTimer, | |
* portBASE_TYPE *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: | |
* | |
* // 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 ) | |
* { | |
* portBASE_TYPE 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. | |
* } | |
* } | |
*/ | |
#define xTimerStopFromISR( xTimer, pxHigherPriorityTaskWoken ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_STOP, 0, ( pxHigherPriorityTaskWoken ), 0U ) | |
/** | |
* portBASE_TYPE xTimerChangePeriodFromISR( xTimerHandle xTimer, | |
* portTickType xNewPeriod, | |
* portBASE_TYPE *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_RATE_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_RATE_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: | |
* | |
* // 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 ) | |
* { | |
* portBASE_TYPE 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. | |
* } | |
* } | |
*/ | |
#define xTimerChangePeriodFromISR( xTimer, xNewPeriod, pxHigherPriorityTaskWoken ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_CHANGE_PERIOD, ( xNewPeriod ), ( pxHigherPriorityTaskWoken ), 0U ) | |
/** | |
* portBASE_TYPE xTimerResetFromISR( xTimerHandle xTimer, | |
* portBASE_TYPE *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: | |
* | |
* // 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( xTimerHandle 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 ) | |
* { | |
* portBASE_TYPE 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. | |
* } | |
* } | |
*/ | |
#define xTimerResetFromISR( xTimer, pxHigherPriorityTaskWoken ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_START, ( xTaskGetTickCountFromISR() ), ( pxHigherPriorityTaskWoken ), 0U ) | |
/* | |
* Functions beyond this part are not part of the public API and are intended | |
* for use by the kernel only. | |
*/ | |
portBASE_TYPE xTimerCreateTimerTask( void ) PRIVILEGED_FUNCTION; | |
portBASE_TYPE xTimerGenericCommand( xTimerHandle xTimer, portBASE_TYPE xCommandID, portTickType xOptionalValue, signed portBASE_TYPE *pxHigherPriorityTaskWoken, portTickType xBlockTime ) PRIVILEGED_FUNCTION; | |
#ifdef __cplusplus | |
} | |
#endif | |
#endif /* TIMERS_H */ | |