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937 lines
43 KiB
C
937 lines
43 KiB
C
/*
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FreeRTOS V7.0.0 - Copyright (C) 2011 Real Time Engineers Ltd.
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FreeRTOS supports many tools and architectures. V7.0.0 is sponsored by:
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Atollic AB - Atollic provides professional embedded systems development
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tools for C/C++ development, code analysis and test automation.
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See http://www.atollic.com
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***************************************************************************
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* *
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* FreeRTOS tutorial books are available in pdf and paperback. *
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* Complete, revised, and edited pdf reference manuals are also *
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* available. *
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* *
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* Purchasing FreeRTOS documentation will not only help you, by *
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* ensuring you get running as quickly as possible and with an *
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* in-depth knowledge of how to use FreeRTOS, it will also help *
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* the FreeRTOS project to continue with its mission of providing *
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* professional grade, cross platform, de facto standard solutions *
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* for microcontrollers - completely free of charge! *
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* *
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* >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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* *
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* Thank you for using FreeRTOS, and thank you for your support! *
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* *
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***************************************************************************
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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>>>NOTE<<< The modification to the GPL is included to allow you to
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distribute a combined work that includes FreeRTOS without being obliged to
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provide the source code for proprietary components outside of the FreeRTOS
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kernel. FreeRTOS is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details. You should have received a copy of the GNU General Public
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License and the FreeRTOS license exception along with FreeRTOS; if not it
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can be viewed here: http://www.freertos.org/a00114.html and also obtained
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by writing to Richard Barry, contact details for whom are available on the
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FreeRTOS WEB site.
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1 tab == 4 spaces!
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http://www.FreeRTOS.org - Documentation, latest information, license and
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contact details.
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http://www.SafeRTOS.com - A version that is certified for use in safety
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critical systems.
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http://www.OpenRTOS.com - Commercial support, development, porting,
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licensing and training services.
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*/
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#ifndef TIMERS_H
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#define TIMERS_H
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#ifndef INC_FREERTOS_H
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#error "include FreeRTOS.h must appear in source files before include timers.h"
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#endif
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#include "portable.h"
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#include "list.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* IDs for commands that can be sent/received on the timer queue. These are to
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be used solely through the macros that make up the public software timer API,
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as defined below. */
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#define tmrCOMMAND_START 0
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#define tmrCOMMAND_STOP 1
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#define tmrCOMMAND_CHANGE_PERIOD 2
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#define tmrCOMMAND_DELETE 3
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/*-----------------------------------------------------------
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* MACROS AND DEFINITIONS
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*----------------------------------------------------------*/
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/**
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* Type by which software timers are referenced. For example, a call to
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* xTimerCreate() returns an xTimerHandle variable that can then be used to
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* reference the subject timer in calls to other software timer API functions
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* (for example, xTimerStart(), xTimerReset(), etc.).
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*/
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typedef void * xTimerHandle;
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/* Define the prototype to which timer callback functions must conform. */
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typedef void (*tmrTIMER_CALLBACK)( xTimerHandle xTimer );
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/**
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* xTimerHandle xTimerCreate( const signed char *pcTimerName,
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* portTickType xTimerPeriod,
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* unsigned portBASE_TYPE uxAutoReload,
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* void * pvTimerID,
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* tmrTIMER_CALLBACK pxCallbackFunction );
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*
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* Creates a new software timer instance. This allocates the storage required
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* by the new timer, initialises the new timers internal state, and returns a
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* handle by which the new timer can be referenced.
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*
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* Timers are created in the dormant state. The xTimerStart(), xTimerReset(),
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* xTimerStartFromISR(), xTimerResetFromISR(), xTimerChangePeriod() and
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* xTimerChangePeriodFromISR() API functions can all be used to transition a timer into the
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* active state.
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*
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* @param pcTimerName A text name that is assigned to the timer. This is done
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* purely to assist debugging. The kernel itself only ever references a timer by
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* its handle, and never by its name.
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*
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* @param xTimerPeriod The timer period. The time is defined in tick periods so
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* the constant portTICK_RATE_MS can be used to convert a time that has been
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* specified in milliseconds. For example, if the timer must expire after 100
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* ticks, then xTimerPeriod should be set to 100. Alternatively, if the timer
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* must expire after 500ms, then xPeriod can be set to ( 500 / portTICK_RATE_MS )
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* provided configTICK_RATE_HZ is less than or equal to 1000.
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*
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* @param uxAutoReload If uxAutoReload is set to pdTRUE then the timer will
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* expire repeatedly with a frequency set by the xTimerPeriod parameter. If
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* uxAutoReload is set to pdFALSE then the timer will be a one-shot timer and
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* enter the dormant state after it expires.
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*
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* @param pvTimerID An identifier that is assigned to the timer being created.
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* Typically this would be used in the timer callback function to identify which
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* timer expired when the same callback function is assigned to more than one
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* timer.
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*
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* @param pxCallbackFunction The function to call when the timer expires.
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* Callback functions must have the prototype defined by tmrTIMER_CALLBACK,
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* which is "void vCallbackFunction( xTIMER *xTimer );".
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*
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* @return If the timer is successfully create then a handle to the newly
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* created timer is returned. If the timer cannot be created (because either
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* there is insufficient FreeRTOS heap remaining to allocate the timer
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* structures, or the timer period was set to 0) then 0 is returned.
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*
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* Example usage:
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*
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*
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* #define NUM_TIMERS 5
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*
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* // An array to hold handles to the created timers.
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* xTimerHandle xTimers[ NUM_TIMERS ];
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*
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* // An array to hold a count of the number of times each timer expires.
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* long lExpireCounters[ NUM_TIMERS ] = { 0 };
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*
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* // Define a callback function that will be used by multiple timer instances.
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* // The callback function does nothing but count the number of times the
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* // associated timer expires, and stop the timer once the timer has expired
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* // 10 times.
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* void vTimerCallback( xTIMER *pxTimer )
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* {
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* long lArrayIndex;
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* const long xMaxExpiryCountBeforeStopping = 10;
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*
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* // Optionally do something if the pxTimer parameter is NULL.
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* configASSERT( pxTimer );
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*
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* // Which timer expired?
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* lArrayIndex = ( long ) pvTimerGetTimerID( pxTimer );
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*
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* // Increment the number of times that pxTimer has expired.
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* lExpireCounters[ lArrayIndex ] += 1;
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*
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* // If the timer has expired 10 times then stop it from running.
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* if( lExpireCounters[ lArrayIndex ] == xMaxExpiryCountBeforeStopping )
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* {
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* // Do not use a block time if calling a timer API function from a
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* // timer callback function, as doing so could cause a deadlock!
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* xTimerStop( pxTimer, 0 );
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* }
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* }
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*
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* void main( void )
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* {
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* long x;
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*
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* // Create then start some timers. Starting the timers before the scheduler
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* // has been started means the timers will start running immediately that
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* // the scheduler starts.
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* for( x = 0; x < NUM_TIMERS; x++ )
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* {
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* xTimers[ x ] = xTimerCreate( "Timer", // Just a text name, not used by the kernel.
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* ( 100 * x ), // The timer period in ticks.
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* pdTRUE, // The timers will auto-reload themselves when they expire.
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* ( void * ) x, // Assign each timer a unique id equal to its array index.
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* vTimerCallback // Each timer calls the same callback when it expires.
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* );
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*
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* if( xTimers[ x ] == NULL )
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* {
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* // The timer was not created.
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* }
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* else
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* {
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* // Start the timer. No block time is specified, and even if one was
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* // it would be ignored because the scheduler has not yet been
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* // started.
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* if( xTimerStart( xTimers[ x ], 0 ) != pdPASS )
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* {
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* // The timer could not be set into the Active state.
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* }
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* }
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* }
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*
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* // ...
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* // Create tasks here.
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* // ...
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*
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* // Starting the scheduler will start the timers running as they have already
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* // been set into the active state.
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* xTaskStartScheduler();
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*
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* // Should not reach here.
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* for( ;; );
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* }
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*/
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xTimerHandle xTimerCreate( const signed char *pcTimerName, portTickType xTimerPeriodInTicks, unsigned portBASE_TYPE uxAutoReload, void * pvTimerID, tmrTIMER_CALLBACK pxCallbackFunction ) PRIVILEGED_FUNCTION;
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/**
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* void *pvTimerGetTimerID( xTimerHandle xTimer );
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*
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* Returns the ID assigned to the timer.
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*
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* IDs are assigned to timers using the pvTimerID parameter of the call to
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* xTimerCreated() that was used to create the timer.
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*
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* If the same callback function is assigned to multiple timers then the timer
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* ID can be used within the callback function to identify which timer actually
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* expired.
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*
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* @param xTimer The timer being queried.
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*
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* @return The ID assigned to the timer being queried.
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*
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* Example usage:
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*
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* See the xTimerCreate() API function example usage scenario.
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*/
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void *pvTimerGetTimerID( xTimerHandle xTimer ) PRIVILEGED_FUNCTION;
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/**
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* portBASE_TYPE xTimerIsTimerActive( xTimerHandle xTimer );
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*
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* Queries a timer to see if it is active or dormant.
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*
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* A timer will be dormant if:
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* 1) It has been created but not started, or
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* 2) It is an expired on-shot timer that has not been restarted.
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*
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* Timers are created in the dormant state. The xTimerStart(), xTimerReset(),
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* xTimerStartFromISR(), xTimerResetFromISR(), xTimerChangePeriod() and
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* xTimerChangePeriodFromISR() API functions can all be used to transition a timer into the
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* active state.
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*
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* @param xTimer The timer being queried.
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*
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* @return pdFALSE will be returned if the timer is dormant. A value other than
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* pdFALSE will be returned if the timer is active.
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*
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* Example usage:
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*
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* // This function assumes xTimer has already been created.
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* void vAFunction( xTimerHandle xTimer )
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* {
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* if( xTimerIsTimerActive( xTimer ) != pdFALSE ) // or more simply and equivalently "if( xTimerIsTimerActive( xTimer ) )"
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* {
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* // xTimer is active, do something.
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* }
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* else
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* {
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* // xTimer is not active, do something else.
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* }
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* }
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*/
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portBASE_TYPE xTimerIsTimerActive( xTimerHandle xTimer ) PRIVILEGED_FUNCTION;
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/**
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* portBASE_TYPE xTimerStart( xTimerHandle xTimer, portTickType xBlockTime );
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*
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* Timer functionality is provided by a timer service/daemon task. Many of the
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* public FreeRTOS timer API functions send commands to the timer service task
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* though a queue called the timer command queue. The timer command queue is
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* private to the kernel itself and is not directly accessible to application
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* code. The length of the timer command queue is set by the
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* configTIMER_QUEUE_LENGTH configuration constant.
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*
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* xTimerStart() starts a timer that was previously created using the
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* xTimerCreate() API function. If the timer had already been started and was
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* already in the active state, then xTimerStart() has equivalent functionality
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* to the xTimerReset() API function.
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*
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* Starting a timer ensures the timer is in the active state. If the timer
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* is not stopped, deleted, or reset in the mean time, the callback function
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* associated with the timer will get called 'n' ticks after xTimerStart() was
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* called, where 'n' is the timers defined period.
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*
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* It is valid to call xTimerStart() before the scheduler has been started, but
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* when this is done the timer will not actually start until the scheduler is
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* started, and the timers expiry time will be relative to when the scheduler is
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* started, not relative to when xTimerStart() was called.
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*
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* The configUSE_TIMERS configuration constant must be set to 1 for xTimerStart()
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* to be available.
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*
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* @param xTimer The handle of the timer being started/restarted.
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*
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* @param xBlockTime Specifies the time, in ticks, that the calling task should
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* be held in the Blocked state to wait for the start command to be successfully
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* sent to the timer command queue, should the queue already be full when
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* xTimerStart() was called. xBlockTime is ignored if xTimerStart() is called
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* before the scheduler is started.
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*
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* @return pdFAIL will be returned if the start command could not be sent to
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* the timer command queue even after xBlockTime ticks had passed. pdPASS will
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* be returned if the command was successfully sent to the timer command queue.
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* When the command is actually processed will depend on the priority of the
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* timer service/daemon task relative to other tasks in the system, although the
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* timers expiry time is relative to when xTimerStart() is actually called. The
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* timer service/daemon task priority is set by the configTIMER_TASK_PRIORITY
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* configuration constant.
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*
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* Example usage:
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*
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* See the xTimerCreate() API function example usage scenario.
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*
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*/
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#define xTimerStart( xTimer, xBlockTime ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_START, ( xTaskGetTickCount() ), NULL, ( xBlockTime ) )
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/**
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* portBASE_TYPE xTimerStop( xTimerHandle xTimer, portTickType xBlockTime );
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*
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* Timer functionality is provided by a timer service/daemon task. Many of the
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* public FreeRTOS timer API functions send commands to the timer service task
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* though a queue called the timer command queue. The timer command queue is
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* private to the kernel itself and is not directly accessible to application
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* code. The length of the timer command queue is set by the
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* configTIMER_QUEUE_LENGTH configuration constant.
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*
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* xTimerStop() stops a timer that was previously started using either of the
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* The xTimerStart(), xTimerReset(), xTimerStartFromISR(), xTimerResetFromISR(),
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* xTimerChangePeriod() or xTimerChangePeriodFromISR() API functions.
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*
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* Stopping a timer ensures the timer is not in the active state.
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*
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* The configUSE_TIMERS configuration constant must be set to 1 for xTimerStop()
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* to be available.
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*
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* @param xTimer The handle of the timer being stopped.
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*
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* @param xBlockTime Specifies the time, in ticks, that the calling task should
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* be held in the Blocked state to wait for the stop command to be successfully
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* sent to the timer command queue, should the queue already be full when
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* xTimerStop() was called. xBlockTime is ignored if xTimerStop() is called
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* before the scheduler is started.
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*
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* @return pdFAIL will be returned if the stop command could not be sent to
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* the timer command queue even after xBlockTime ticks had passed. pdPASS will
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* be returned if the command was successfully sent to the timer command queue.
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* When the command is actually processed will depend on the priority of the
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* timer service/daemon task relative to other tasks in the system. The timer
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* service/daemon task priority is set by the configTIMER_TASK_PRIORITY
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* configuration constant.
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*
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* Example usage:
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*
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* See the xTimerCreate() API function example usage scenario.
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*
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*/
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#define xTimerStop( xTimer, xBlockTime ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_STOP, 0U, NULL, ( xBlockTime ) )
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/**
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* portBASE_TYPE xTimerChangePeriod( xTimerHandle xTimer,
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* portTickType xNewPeriod,
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* portTickType xBlockTime );
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*
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* Timer functionality is provided by a timer service/daemon task. Many of the
|
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* public FreeRTOS timer API functions send commands to the timer service task
|
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* though a queue called the timer command queue. The timer command queue is
|
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* private to the kernel itself and is not directly accessible to application
|
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* code. The length of the timer command queue is set by the
|
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* configTIMER_QUEUE_LENGTH configuration constant.
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*
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* xTimerChangePeriod() changes the period of a timer that was previously
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* created using the xTimerCreate() API function.
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*
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* xTimerChangePeriod() can be called to change the period of an active or
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* dormant state timer.
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*
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* The configUSE_TIMERS configuration constant must be set to 1 for
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* xTimerChangePeriod() to be available.
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*
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* @param xTimer The handle of the timer that is having its period changed.
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*
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* @param xNewPeriod The new period for xTimer. Timer periods are specified in
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* tick periods, so the constant portTICK_RATE_MS can be used to convert a time
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* that has been specified in milliseconds. For example, if the timer must
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* expire after 100 ticks, then xNewPeriod should be set to 100. Alternatively,
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* if the timer must expire after 500ms, then xNewPeriod can be set to
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* ( 500 / portTICK_RATE_MS ) provided configTICK_RATE_HZ is less than
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* or equal to 1000.
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*
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* @param xBlockTime Specifies the time, in ticks, that the calling task should
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* be held in the Blocked state to wait for the change period command to be
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* successfully sent to the timer command queue, should the queue already be
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* full when xTimerChangePeriod() was called. xBlockTime is ignored if
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* xTimerChangePeriod() is called before the scheduler is started.
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*
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* @return pdFAIL will be returned if the change period command could not be
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* sent to the timer command queue even after xBlockTime ticks had passed.
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* pdPASS will be returned if the command was successfully sent to the timer
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* command queue. When the command is actually processed will depend on the
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* priority of the timer service/daemon task relative to other tasks in the
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* system. The timer service/daemon task priority is set by the
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* configTIMER_TASK_PRIORITY configuration constant.
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*
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* Example usage:
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*
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* // This function assumes xTimer has already been created. If the timer
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* // referenced by xTimer is already active when it is called, then the timer
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* // is deleted. If the timer referenced by xTimer is not active when it is
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* // called, then the period of the timer is set to 500ms and the timer is
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* // started.
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* void vAFunction( xTimerHandle xTimer )
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* {
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* if( xTimerIsTimerActive( xTimer ) != pdFALSE ) // or more simply and equivalently "if( xTimerIsTimerActive( xTimer ) )"
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* {
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* // xTimer is already active - delete it.
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* xTimerDelete( xTimer );
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* }
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* else
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* {
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* // xTimer is not active, change its period to 500ms. This will also
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* // cause the timer to start. Block for a maximum of 100 ticks if the
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* // change period command cannot immediately be sent to the timer
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* // command queue.
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* if( xTimerChangePeriod( xTimer, 500 / portTICK_RATE_MS, 100 ) == pdPASS )
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* {
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* // The command was successfully sent.
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* }
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* else
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* {
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* // The command could not be sent, even after waiting for 100 ticks
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* // to pass. Take appropriate action here.
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* }
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* }
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* }
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*/
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#define xTimerChangePeriod( xTimer, xNewPeriod, xBlockTime ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_CHANGE_PERIOD, ( xNewPeriod ), NULL, ( xBlockTime ) )
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/**
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* portBASE_TYPE xTimerDelete( xTimerHandle xTimer, portTickType xBlockTime );
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*
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* Timer functionality is provided by a timer service/daemon task. Many of the
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* public FreeRTOS timer API functions send commands to the timer service task
|
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* though a queue called the timer command queue. The timer command queue is
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* private to the kernel itself and is not directly accessible to application
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* code. The length of the timer command queue is set by the
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* configTIMER_QUEUE_LENGTH configuration constant.
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*
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* xTimerDelete() deletes a timer that was previously created using the
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* xTimerCreate() API function.
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*
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* The configUSE_TIMERS configuration constant must be set to 1 for
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* xTimerDelete() to be available.
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*
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* @param xTimer The handle of the timer being deleted.
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*
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* @param xBlockTime Specifies the time, in ticks, that the calling task should
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* be held in the Blocked state to wait for the delete command to be
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* successfully sent to the timer command queue, should the queue already be
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* full when xTimerDelete() was called. xBlockTime is ignored if xTimerDelete()
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* is called before the scheduler is started.
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*
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* @return pdFAIL will be returned if the delete command could not be sent to
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* the timer command queue even after xBlockTime ticks had passed. pdPASS will
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* be returned if the command was successfully sent to the timer command queue.
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* When the command is actually processed will depend on the priority of the
|
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* timer service/daemon task relative to other tasks in the system. The timer
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* service/daemon task priority is set by the configTIMER_TASK_PRIORITY
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* configuration constant.
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*
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* Example usage:
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*
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* See the xTimerChangePeriod() API function example usage scenario.
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*/
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#define xTimerDelete( xTimer, xBlockTime ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_DELETE, 0U, NULL, ( xBlockTime ) )
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/**
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* portBASE_TYPE xTimerReset( xTimerHandle xTimer, portTickType xBlockTime );
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*
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* 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
|
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* configTIMER_QUEUE_LENGTH configuration constant.
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*
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* xTimerReset() re-starts a timer that was previously created using the
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* xTimerCreate() API function. If the timer had already been started and was
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* already in the active state, then xTimerReset() will cause the timer to
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* re-evaluate its expiry time so that it is relative to when xTimerReset() was
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* called. If the timer was in the dormant state then xTimerReset() has
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* equivalent functionality to the xTimerStart() API function.
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*
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* Resetting a timer ensures the timer is in the active state. If the timer
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* is not stopped, deleted, or reset in the mean time, the callback function
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* associated with the timer will get called 'n' ticks after xTimerReset() was
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* called, where 'n' is the timers defined period.
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*
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* It is valid to call xTimerReset() before the scheduler has been started, but
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* when this is done the timer will not actually start until the scheduler is
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* started, and the timers expiry time will be relative to when the scheduler is
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* started, not relative to when xTimerReset() was called.
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*
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* The configUSE_TIMERS configuration constant must be set to 1 for xTimerReset()
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* to be available.
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*
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* @param xTimer The handle of the timer being reset/started/restarted.
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*
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* @param xBlockTime Specifies the time, in ticks, that the calling task should
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* be held in the Blocked state to wait for the reset command to be successfully
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* sent to the timer command queue, should the queue already be full when
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* xTimerReset() was called. xBlockTime is ignored if xTimerReset() is called
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* before the scheduler is started.
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*
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* @return pdFAIL will be returned if the reset command could not be sent to
|
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* the timer command queue even after xBlockTime ticks had passed. pdPASS will
|
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* be returned if the command was successfully sent to the timer command queue.
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* When the command is actually processed will depend on the priority of the
|
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* timer service/daemon task relative to other tasks in the system, although the
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* timers expiry time is relative to when xTimerStart() is actually called. The
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* timer service/daemon task priority is set by the configTIMER_TASK_PRIORITY
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* configuration constant.
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*
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* Example usage:
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*
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* // When a key is pressed, an LCD back-light is switched on. If 5 seconds pass
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* // without a key being pressed, then the LCD back-light is switched off. In
|
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* // this case, the timer is a one-shot timer.
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*
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* xTimerHandle xBacklightTimer = NULL;
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*
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* // The callback function assigned to the one-shot timer. In this case the
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* // parameter is not used.
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* void vBacklightTimerCallback( xTIMER *pxTimer )
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* {
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* // The timer expired, therefore 5 seconds must have passed since a key
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* // was pressed. Switch off the LCD back-light.
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* vSetBacklightState( BACKLIGHT_OFF );
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* }
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*
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* // The key press event handler.
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* void vKeyPressEventHandler( char cKey )
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* {
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* // Ensure the LCD back-light is on, then reset the timer that is
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* // responsible for turning the back-light off after 5 seconds of
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* // key inactivity. Wait 10 ticks for the command to be successfully sent
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* // if it cannot be sent immediately.
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* vSetBacklightState( BACKLIGHT_ON );
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* if( xTimerReset( xBacklightTimer, 100 ) != pdPASS )
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* {
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* // The reset command was not executed successfully. Take appropriate
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* // action here.
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* }
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*
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* // Perform the rest of the key processing here.
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* }
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*
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* void main( void )
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* {
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* long x;
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*
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* // Create then start the one-shot timer that is responsible for turning
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* // the back-light off if no keys are pressed within a 5 second period.
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* xBacklightTimer = xTimerCreate( "BacklightTimer", // Just a text name, not used by the kernel.
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* ( 5000 / portTICK_RATE_MS), // The timer period in ticks.
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* pdFALSE, // The timer is a one-shot timer.
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* 0, // The id is not used by the callback so can take any value.
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* vBacklightTimerCallback // The callback function that switches the LCD back-light off.
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* );
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*
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* if( xBacklightTimer == NULL )
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* {
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* // The timer was not created.
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|
* }
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|
* else
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|
* {
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* // Start the timer. No block time is specified, and even if one was
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* // it would be ignored because the scheduler has not yet been
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* // started.
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* if( xTimerStart( xBacklightTimer, 0 ) != pdPASS )
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* {
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* // The timer could not be set into the Active state.
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|
* }
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|
* }
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*
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|
* // ...
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* // Create tasks here.
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* // ...
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*
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* // Starting the scheduler will start the timer running as it has already
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* // been set into the active state.
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* xTaskStartScheduler();
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*
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|
* // Should not reach here.
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|
* for( ;; );
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|
* }
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*/
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#define xTimerReset( xTimer, xBlockTime ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_START, ( xTaskGetTickCount() ), NULL, ( xBlockTime ) )
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|
|
/**
|
|
* portBASE_TYPE xTimerStartFromISR( xTimerHandle xTimer,
|
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* portBASE_TYPE *pxHigherPriorityTaskWoken );
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*
|
|
* A version of xTimerStart() that can be called from an interrupt service
|
|
* routine.
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|
*
|
|
* @param xTimer The handle of the timer being started/restarted.
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|
*
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|
* @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( xTIMER *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( xTIMER *pxTimer )
|
|
* {
|
|
* // The timer expired, therefore 5 seconds must have passed since a key
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* // was pressed. Switch off the LCD back-light.
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* vSetBacklightState( BACKLIGHT_OFF );
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|
* }
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*
|
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* // The key press interrupt service routine.
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|
* void vKeyPressEventInterruptHandler( void )
|
|
* {
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|
* portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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|
*
|
|
* // 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 );
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|
*
|
|
* // xTimerStartFromISR() or xTimerResetFromISR() could be called here
|
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* // 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, portBASE_TYPE *pxHigherPriorityTaskWoken, portTickType xBlockTime ) PRIVILEGED_FUNCTION;
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
#endif /* TIMERS_H */
|
|
|
|
|
|
|