mirror of
https://github.com/espressif/esp-idf.git
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cda22d9aaf
- Use `code` tags instead of a mix of `<pre></pre>` and `@verbatim .. @endverbatim` - Remove manually added function prototypes from comment blocks - Remove of grouping (`\defgroup`) — some extra work is needed to make groups compatible with the way we auto-generate API reference from Doxygen XML files. It's pretty easy to add the grouping directives back if/when we implement support for Doxygen groups in the later stages of documentation build process. - Hide private APIs under `@cond .. @endcond` - Convert some comments into Doxygen-compatible ones - Fix various documentation issues: missing documentation for some parameters, mismatch between parameter names in comment block and in function prototype. - Add doxygen comments for functions which didn't have them (thread local storage). - Add [out] param tags where necessary - Redefine `xTaskCreate` and `xTaskCreateStatic` as inline functions instead of macros.
1259 lines
57 KiB
C
1259 lines
57 KiB
C
/*
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FreeRTOS V8.2.0 - Copyright (C) 2015 Real Time Engineers Ltd.
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All rights reserved
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VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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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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***************************************************************************
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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 !<<
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>>! obliged to provide the source code for proprietary components !<<
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>>! outside of the FreeRTOS kernel. !<<
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***************************************************************************
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. Full license text is available on the following
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link: http://www.freertos.org/a00114.html
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***************************************************************************
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* *
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* FreeRTOS provides completely free yet professionally developed, *
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* robust, strictly quality controlled, supported, and cross *
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* platform software that is more than just the market leader, it *
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* is the industry's de facto standard. *
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* *
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* Help yourself get started quickly while simultaneously helping *
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* to support the FreeRTOS project by purchasing a FreeRTOS *
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* tutorial book, reference manual, or both: *
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* http://www.FreeRTOS.org/Documentation *
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* *
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***************************************************************************
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http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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the FAQ page "My application does not run, what could be wrong?". Have you
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defined configASSERT()?
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http://www.FreeRTOS.org/support - In return for receiving this top quality
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embedded software for free we request you assist our global community by
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participating in the support forum.
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http://www.FreeRTOS.org/training - Investing in training allows your team to
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be as productive as possible as early as possible. Now you can receive
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FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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Ltd, and the world's leading authority on the world's leading RTOS.
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http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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compatible FAT file system, and our tiny thread aware UDP/IP stack.
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http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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licenses offer ticketed support, indemnification and commercial middleware.
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http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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engineered and independently SIL3 certified version for use in safety and
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mission critical applications that require provable dependability.
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1 tab == 4 spaces!
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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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/*lint -e537 This headers are only multiply included if the application code
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happens to also be including task.h. */
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#include "task.h"
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/*lint +e537 */
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*-----------------------------------------------------------
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* MACROS AND DEFINITIONS
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*----------------------------------------------------------*/
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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. The commands that are sent from interrupts must use the
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highest numbers as tmrFIRST_FROM_ISR_COMMAND is used to determine if the task
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or interrupt version of the queue send function should be used. */
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#define tmrCOMMAND_EXECUTE_CALLBACK_FROM_ISR ( ( BaseType_t ) -2 )
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#define tmrCOMMAND_EXECUTE_CALLBACK ( ( BaseType_t ) -1 )
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#define tmrCOMMAND_START_DONT_TRACE ( ( BaseType_t ) 0 )
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#define tmrCOMMAND_START ( ( BaseType_t ) 1 )
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#define tmrCOMMAND_RESET ( ( BaseType_t ) 2 )
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#define tmrCOMMAND_STOP ( ( BaseType_t ) 3 )
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#define tmrCOMMAND_CHANGE_PERIOD ( ( BaseType_t ) 4 )
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#define tmrCOMMAND_DELETE ( ( BaseType_t ) 5 )
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#define tmrFIRST_FROM_ISR_COMMAND ( ( BaseType_t ) 6 )
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#define tmrCOMMAND_START_FROM_ISR ( ( BaseType_t ) 6 )
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#define tmrCOMMAND_RESET_FROM_ISR ( ( BaseType_t ) 7 )
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#define tmrCOMMAND_STOP_FROM_ISR ( ( BaseType_t ) 8 )
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#define tmrCOMMAND_CHANGE_PERIOD_FROM_ISR ( ( BaseType_t ) 9 )
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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 TimerHandle_t 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 * TimerHandle_t;
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/**
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* Defines the prototype to which timer callback functions must conform.
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*/
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typedef void (*TimerCallbackFunction_t)( TimerHandle_t xTimer );
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/**
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* Defines the prototype to which functions used with the
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* xTimerPendFunctionCallFromISR() function must conform.
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*/
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typedef void (*PendedFunction_t)( void *, uint32_t );
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/**
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* Creates a new software timer instance, and returns a handle by which the
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* created software timer can be referenced.
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*
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* Internally, within the FreeRTOS implementation, software timers use a block
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* of memory, in which the timer data structure is stored. If a software timer
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* is created using xTimerCreate() then the required memory is automatically
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* dynamically allocated inside the xTimerCreate() function. (see
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* http://www.freertos.org/a00111.html). If a software timer is created using
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* xTimerCreateStatic() then the application writer must provide the memory that
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* will get used by the software timer. xTimerCreateStatic() therefore allows a
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* software timer to be created without using any dynamic memory allocation.
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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
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* timer into the 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
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* by its handle, and never by its name.
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*
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* @param xTimerPeriodInTicks The timer period. The time is defined in tick
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* periods so the constant portTICK_PERIOD_MS can be used to convert a time that
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* has been specified in milliseconds. For example, if the timer must expire
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* after 100 ticks, then xTimerPeriodInTicks should be set to 100.
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* Alternatively, if the timer must expire after 500ms, then xPeriod can be set
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* to ( 500 / portTICK_PERIOD_MS ) provided configTICK_RATE_HZ is less than or
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* 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 xTimerPeriodInTicks parameter.
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* If 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 TimerCallbackFunction_t,
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* which is "void vCallbackFunction( TimerHandle_t xTimer );".
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*
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* @return If the timer is successfully created 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 NULL is returned.
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*
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* Example usage:
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* @code{c}
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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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* TimerHandle_t 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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* int32_t 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( TimerHandle_t pxTimer )
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* {
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* int32_t lArrayIndex;
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* const int32_t 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 = ( int32_t ) 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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* int32_t 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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* vTaskStartScheduler();
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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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* @endcode
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*/
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#if( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
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TimerHandle_t xTimerCreate( const char * const pcTimerName,
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const TickType_t xTimerPeriodInTicks,
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const UBaseType_t uxAutoReload,
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void * const pvTimerID,
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TimerCallbackFunction_t pxCallbackFunction ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
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#endif
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/**
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* Creates a new software timer instance, and returns a handle by which the
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* created software timer can be referenced.
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|
*
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|
* Internally, within the FreeRTOS implementation, software timers use a block
|
|
* of memory, in which the timer data structure is stored. If a software timer
|
|
* is created using xTimerCreate() then the required memory is automatically
|
|
* dynamically allocated inside the xTimerCreate() function. (see
|
|
* http://www.freertos.org/a00111.html). If a software timer is created using
|
|
* xTimerCreateStatic() then the application writer must provide the memory that
|
|
* will get used by the software timer. xTimerCreateStatic() therefore allows a
|
|
* software timer to be created without using any dynamic memory allocation.
|
|
*
|
|
* Timers are created in the dormant state. The xTimerStart(), xTimerReset(),
|
|
* xTimerStartFromISR(), xTimerResetFromISR(), xTimerChangePeriod() and
|
|
* xTimerChangePeriodFromISR() API functions can all be used to transition a
|
|
* timer into the active state.
|
|
*
|
|
* @param pcTimerName A text name that is assigned to the timer. This is done
|
|
* purely to assist debugging. The kernel itself only ever references a timer
|
|
* by its handle, and never by its name.
|
|
*
|
|
* @param xTimerPeriodInTicks The timer period. The time is defined in tick
|
|
* periods so the constant portTICK_PERIOD_MS can be used to convert a time that
|
|
* has been specified in milliseconds. For example, if the timer must expire
|
|
* after 100 ticks, then xTimerPeriodInTicks should be set to 100.
|
|
* Alternatively, if the timer must expire after 500ms, then xPeriod can be set
|
|
* to ( 500 / portTICK_PERIOD_MS ) provided configTICK_RATE_HZ is less than or
|
|
* equal to 1000.
|
|
*
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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 xTimerPeriodInTicks parameter.
|
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* If uxAutoReload is set to pdFALSE then the timer will be a one-shot timer and
|
|
* enter the dormant state after it expires.
|
|
*
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|
* @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.
|
|
*
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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 TimerCallbackFunction_t,
|
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* which is "void vCallbackFunction( TimerHandle_t xTimer );".
|
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*
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* @param pxTimerBuffer Must point to a variable of type StaticTimer_t, which
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* will be then be used to hold the software timer's data structures, removing
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* the need for the memory to be allocated dynamically.
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*
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* @return If the timer is created then a handle to the created timer is
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* returned. If pxTimerBuffer was NULL then NULL is returned.
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*
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* Example usage:
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* @code{c}
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*
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* // The buffer used to hold the software timer's data structure.
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* static StaticTimer_t xTimerBuffer;
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*
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* // A variable that will be incremented by the software timer's callback
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* // function.
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* UBaseType_t uxVariableToIncrement = 0;
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*
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* // A software timer callback function that increments a variable passed to
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* // it when the software timer was created. After the 5th increment the
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* // callback function stops the software timer.
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* static void prvTimerCallback( TimerHandle_t xExpiredTimer )
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* {
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* UBaseType_t *puxVariableToIncrement;
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* BaseType_t xReturned;
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*
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* // Obtain the address of the variable to increment from the timer ID.
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* puxVariableToIncrement = ( UBaseType_t * ) pvTimerGetTimerID( xExpiredTimer );
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*
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* // Increment the variable to show the timer callback has executed.
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* ( *puxVariableToIncrement )++;
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*
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* // If this callback has executed the required number of times, stop the
|
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* // timer.
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* if( *puxVariableToIncrement == 5 )
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* {
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* // This is called from a timer callback so must not block.
|
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* xTimerStop( xExpiredTimer, staticDONT_BLOCK );
|
|
* }
|
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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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* // Create the software time. xTimerCreateStatic() has an extra parameter
|
|
* // than the normal xTimerCreate() API function. The parameter is a pointer
|
|
* // to the StaticTimer_t structure that will hold the software timer
|
|
* // structure. If the parameter is passed as NULL then the structure will be
|
|
* // allocated dynamically, just as if xTimerCreate() had been called.
|
|
* xTimer = xTimerCreateStatic( "T1", // Text name for the task. Helps debugging only. Not used by FreeRTOS.
|
|
* xTimerPeriod, // The period of the timer in ticks.
|
|
* pdTRUE, // This is an auto-reload timer.
|
|
* ( void * ) &uxVariableToIncrement, // A variable incremented by the software timer's callback function
|
|
* prvTimerCallback, // The function to execute when the timer expires.
|
|
* &xTimerBuffer ); // The buffer that will hold the software timer structure.
|
|
*
|
|
* // The scheduler has not started yet so a block time is not used.
|
|
* xReturned = xTimerStart( xTimer, 0 );
|
|
*
|
|
* // ...
|
|
* // Create tasks here.
|
|
* // ...
|
|
*
|
|
* // Starting the scheduler will start the timers running as they have already
|
|
* // been set into the active state.
|
|
* vTaskStartScheduler();
|
|
*
|
|
* // Should not reach here.
|
|
* for( ;; );
|
|
* }
|
|
* @endcode
|
|
*/
|
|
#if( configSUPPORT_STATIC_ALLOCATION == 1 )
|
|
TimerHandle_t xTimerCreateStatic( const char * const pcTimerName,
|
|
const TickType_t xTimerPeriodInTicks,
|
|
const UBaseType_t uxAutoReload,
|
|
void * const pvTimerID,
|
|
TimerCallbackFunction_t pxCallbackFunction,
|
|
StaticTimer_t *pxTimerBuffer ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
|
|
#endif /* configSUPPORT_STATIC_ALLOCATION */
|
|
|
|
/**
|
|
* 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( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* Sets the ID assigned to the timer.
|
|
*
|
|
* IDs are assigned to timers using the pvTimerID parameter of the call to
|
|
* xTimerCreated() that was used to create the timer.
|
|
*
|
|
* If the same callback function is assigned to multiple timers then the timer
|
|
* ID can be used as time specific (timer local) storage.
|
|
*
|
|
* @param xTimer The timer being updated.
|
|
*
|
|
* @param pvNewID The ID to assign to the timer.
|
|
*
|
|
* Example usage:
|
|
*
|
|
* See the xTimerCreate() API function example usage scenario.
|
|
*/
|
|
void vTimerSetTimerID( TimerHandle_t xTimer, void *pvNewID ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* Queries a timer to see if it is active or dormant.
|
|
*
|
|
* A timer will be dormant if:
|
|
*
|
|
* 1) It has been created but not started, or
|
|
*
|
|
* 2) It is an expired one-shot timer that has not been restarted.
|
|
*
|
|
* Timers are created in the dormant state. The xTimerStart(), xTimerReset(),
|
|
* xTimerStartFromISR(), xTimerResetFromISR(), xTimerChangePeriod() and
|
|
* xTimerChangePeriodFromISR() API functions can all be used to transition a timer into the
|
|
* active state.
|
|
*
|
|
* @param xTimer The timer being queried.
|
|
*
|
|
* @return pdFALSE will be returned if the timer is dormant. A value other than
|
|
* pdFALSE will be returned if the timer is active.
|
|
*
|
|
* Example usage:
|
|
* @code{c}
|
|
* // This function assumes xTimer has already been created.
|
|
* void vAFunction( TimerHandle_t xTimer )
|
|
* {
|
|
* if( xTimerIsTimerActive( xTimer ) != pdFALSE ) // or more simply and equivalently "if( xTimerIsTimerActive( xTimer ) )"
|
|
* {
|
|
* // xTimer is active, do something.
|
|
* }
|
|
* else
|
|
* {
|
|
* // xTimer is not active, do something else.
|
|
* }
|
|
* }
|
|
* @endcode
|
|
*/
|
|
BaseType_t xTimerIsTimerActive( TimerHandle_t 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.
|
|
*/
|
|
TaskHandle_t xTimerGetTimerDaemonTaskHandle( void );
|
|
|
|
/**
|
|
* Returns the period of a timer.
|
|
*
|
|
* @param xTimer The handle of the timer being queried.
|
|
*
|
|
* @return The period of the timer in ticks.
|
|
*/
|
|
TickType_t xTimerGetPeriod( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* Returns the time in ticks at which the timer will expire. If this is less
|
|
* than the current tick count then the expiry time has overflowed from the
|
|
* current time.
|
|
*
|
|
* @param xTimer The handle of the timer being queried.
|
|
*
|
|
* @return If the timer is running then the time in ticks at which the timer
|
|
* will next expire is returned. If the timer is not running then the return
|
|
* value is undefined.
|
|
*/
|
|
TickType_t xTimerGetExpiryTime( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* Timer functionality is provided by a timer service/daemon task. Many of the
|
|
* public FreeRTOS timer API functions send commands to the timer service task
|
|
* through a queue called the timer command queue. The timer command queue is
|
|
* private to the kernel itself and is not directly accessible to application
|
|
* code. The length of the timer command queue is set by the
|
|
* configTIMER_QUEUE_LENGTH configuration constant.
|
|
*
|
|
* xTimerStart() starts a timer that was previously created using the
|
|
* xTimerCreate() API function. If the timer had already been started and was
|
|
* already in the active state, then xTimerStart() has equivalent functionality
|
|
* to the xTimerReset() API function.
|
|
*
|
|
* Starting a timer ensures the timer is in the active state. If the timer
|
|
* is not stopped, deleted, or reset in the mean time, the callback function
|
|
* associated with the timer will get called 'n' ticks after xTimerStart() was
|
|
* called, where 'n' is the timers defined period.
|
|
*
|
|
* It is valid to call xTimerStart() before the scheduler has been started, but
|
|
* when this is done the timer will not actually start until the scheduler is
|
|
* started, and the timers expiry time will be relative to when the scheduler is
|
|
* started, not relative to when xTimerStart() was called.
|
|
*
|
|
* The configUSE_TIMERS configuration constant must be set to 1 for xTimerStart()
|
|
* to be available.
|
|
*
|
|
* @param xTimer The handle of the timer being started/restarted.
|
|
*
|
|
* @param xTicksToWait Specifies the time, in ticks, that the calling task should
|
|
* be held in the Blocked state to wait for the start command to be successfully
|
|
* sent to the timer command queue, should the queue already be full when
|
|
* xTimerStart() was called. xTicksToWait is ignored if xTimerStart() is called
|
|
* before the scheduler is started.
|
|
*
|
|
* @return pdFAIL will be returned if the start command could not be sent to
|
|
* the timer command queue even after xTicksToWait ticks had passed. pdPASS will
|
|
* be returned if the command was successfully sent to the timer command queue.
|
|
* When the command is actually processed will depend on the priority of the
|
|
* timer service/daemon task relative to other tasks in the system, although the
|
|
* timers expiry time is relative to when xTimerStart() is actually called. The
|
|
* timer service/daemon task priority is set by the configTIMER_TASK_PRIORITY
|
|
* configuration constant.
|
|
*
|
|
* Example usage:
|
|
*
|
|
* See the xTimerCreate() API function example usage scenario.
|
|
*
|
|
*/
|
|
#define xTimerStart( xTimer, xTicksToWait ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_START, ( xTaskGetTickCount() ), NULL, ( xTicksToWait ) )
|
|
|
|
/**
|
|
* Timer functionality is provided by a timer service/daemon task. Many of the
|
|
* public FreeRTOS timer API functions send commands to the timer service task
|
|
* through a queue called the timer command queue. The timer command queue is
|
|
* private to the kernel itself and is not directly accessible to application
|
|
* code. The length of the timer command queue is set by the
|
|
* configTIMER_QUEUE_LENGTH configuration constant.
|
|
*
|
|
* xTimerStop() stops a timer that was previously started using either of the
|
|
* The xTimerStart(), xTimerReset(), xTimerStartFromISR(), xTimerResetFromISR(),
|
|
* xTimerChangePeriod() or xTimerChangePeriodFromISR() API functions.
|
|
*
|
|
* Stopping a timer ensures the timer is not in the active state.
|
|
*
|
|
* The configUSE_TIMERS configuration constant must be set to 1 for xTimerStop()
|
|
* to be available.
|
|
*
|
|
* @param xTimer The handle of the timer being stopped.
|
|
*
|
|
* @param xTicksToWait Specifies the time, in ticks, that the calling task should
|
|
* be held in the Blocked state to wait for the stop command to be successfully
|
|
* sent to the timer command queue, should the queue already be full when
|
|
* xTimerStop() was called. xTicksToWait is ignored if xTimerStop() is called
|
|
* before the scheduler is started.
|
|
*
|
|
* @return pdFAIL will be returned if the stop command could not be sent to
|
|
* the timer command queue even after xTicksToWait ticks had passed. pdPASS will
|
|
* be returned if the command was successfully sent to the timer command queue.
|
|
* When the command is actually processed will depend on the priority of the
|
|
* timer service/daemon task relative to other tasks in the system. The timer
|
|
* service/daemon task priority is set by the configTIMER_TASK_PRIORITY
|
|
* configuration constant.
|
|
*
|
|
* Example usage:
|
|
*
|
|
* See the xTimerCreate() API function example usage scenario.
|
|
*
|
|
*/
|
|
#define xTimerStop( xTimer, xTicksToWait ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_STOP, 0U, NULL, ( xTicksToWait ) )
|
|
|
|
/**
|
|
* Timer functionality is provided by a timer service/daemon task. Many of the
|
|
* public FreeRTOS timer API functions send commands to the timer service task
|
|
* through a queue called the timer command queue. The timer command queue is
|
|
* private to the kernel itself and is not directly accessible to application
|
|
* code. The length of the timer command queue is set by the
|
|
* configTIMER_QUEUE_LENGTH configuration constant.
|
|
*
|
|
* xTimerChangePeriod() changes the period of a timer that was previously
|
|
* created using the xTimerCreate() API function.
|
|
*
|
|
* xTimerChangePeriod() can be called to change the period of an active or
|
|
* dormant state timer.
|
|
*
|
|
* The configUSE_TIMERS configuration constant must be set to 1 for
|
|
* xTimerChangePeriod() to be available.
|
|
*
|
|
* @param xTimer The handle of the timer that is having its period changed.
|
|
*
|
|
* @param xNewPeriod The new period for xTimer. Timer periods are specified in
|
|
* tick periods, so the constant portTICK_PERIOD_MS can be used to convert a time
|
|
* that has been specified in milliseconds. For example, if the timer must
|
|
* expire after 100 ticks, then xNewPeriod should be set to 100. Alternatively,
|
|
* if the timer must expire after 500ms, then xNewPeriod can be set to
|
|
* ( 500 / portTICK_PERIOD_MS ) provided configTICK_RATE_HZ is less than
|
|
* or equal to 1000.
|
|
*
|
|
* @param xTicksToWait Specifies the time, in ticks, that the calling task should
|
|
* be held in the Blocked state to wait for the change period command to be
|
|
* successfully sent to the timer command queue, should the queue already be
|
|
* full when xTimerChangePeriod() was called. xTicksToWait is ignored if
|
|
* xTimerChangePeriod() is called before the scheduler is started.
|
|
*
|
|
* @return pdFAIL will be returned if the change period command could not be
|
|
* sent to the timer command queue even after xTicksToWait ticks had passed.
|
|
* pdPASS will be returned if the command was successfully sent to the timer
|
|
* command queue. When the command is actually processed will depend on the
|
|
* priority of the timer service/daemon task relative to other tasks in the
|
|
* system. The timer service/daemon task priority is set by the
|
|
* configTIMER_TASK_PRIORITY configuration constant.
|
|
*
|
|
* Example usage:
|
|
* @code{c}
|
|
* // This function assumes xTimer has already been created. If the timer
|
|
* // referenced by xTimer is already active when it is called, then the timer
|
|
* // is deleted. If the timer referenced by xTimer is not active when it is
|
|
* // called, then the period of the timer is set to 500ms and the timer is
|
|
* // started.
|
|
* void vAFunction( TimerHandle_t xTimer )
|
|
* {
|
|
* if( xTimerIsTimerActive( xTimer ) != pdFALSE ) // or more simply and equivalently "if( xTimerIsTimerActive( xTimer ) )"
|
|
* {
|
|
* // xTimer is already active - delete it.
|
|
* xTimerDelete( xTimer );
|
|
* }
|
|
* else
|
|
* {
|
|
* // xTimer is not active, change its period to 500ms. This will also
|
|
* // cause the timer to start. Block for a maximum of 100 ticks if the
|
|
* // change period command cannot immediately be sent to the timer
|
|
* // command queue.
|
|
* if( xTimerChangePeriod( xTimer, 500 / portTICK_PERIOD_MS, 100 ) == pdPASS )
|
|
* {
|
|
* // The command was successfully sent.
|
|
* }
|
|
* else
|
|
* {
|
|
* // The command could not be sent, even after waiting for 100 ticks
|
|
* // to pass. Take appropriate action here.
|
|
* }
|
|
* }
|
|
* }
|
|
* @endcode
|
|
*/
|
|
#define xTimerChangePeriod( xTimer, xNewPeriod, xTicksToWait ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_CHANGE_PERIOD, ( xNewPeriod ), NULL, ( xTicksToWait ) )
|
|
|
|
/**
|
|
* Timer functionality is provided by a timer service/daemon task. Many of the
|
|
* public FreeRTOS timer API functions send commands to the timer service task
|
|
* through a queue called the timer command queue. The timer command queue is
|
|
* private to the kernel itself and is not directly accessible to application
|
|
* code. The length of the timer command queue is set by the
|
|
* configTIMER_QUEUE_LENGTH configuration constant.
|
|
*
|
|
* xTimerDelete() deletes a timer that was previously created using the
|
|
* xTimerCreate() API function.
|
|
*
|
|
* The configUSE_TIMERS configuration constant must be set to 1 for
|
|
* xTimerDelete() to be available.
|
|
*
|
|
* @param xTimer The handle of the timer being deleted.
|
|
*
|
|
* @param xTicksToWait Specifies the time, in ticks, that the calling task should
|
|
* be held in the Blocked state to wait for the delete command to be
|
|
* successfully sent to the timer command queue, should the queue already be
|
|
* full when xTimerDelete() was called. xTicksToWait is ignored if xTimerDelete()
|
|
* is called before the scheduler is started.
|
|
*
|
|
* @return pdFAIL will be returned if the delete command could not be sent to
|
|
* the timer command queue even after xTicksToWait ticks had passed. pdPASS will
|
|
* be returned if the command was successfully sent to the timer command queue.
|
|
* When the command is actually processed will depend on the priority of the
|
|
* timer service/daemon task relative to other tasks in the system. The timer
|
|
* service/daemon task priority is set by the configTIMER_TASK_PRIORITY
|
|
* configuration constant.
|
|
*
|
|
* Example usage:
|
|
*
|
|
* See the xTimerChangePeriod() API function example usage scenario.
|
|
*/
|
|
#define xTimerDelete( xTimer, xTicksToWait ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_DELETE, 0U, NULL, ( xTicksToWait ) )
|
|
|
|
/**
|
|
* Timer functionality is provided by a timer service/daemon task. Many of the
|
|
* public FreeRTOS timer API functions send commands to the timer service task
|
|
* through a queue called the timer command queue. The timer command queue is
|
|
* private to the kernel itself and is not directly accessible to application
|
|
* code. The length of the timer command queue is set by the
|
|
* configTIMER_QUEUE_LENGTH configuration constant.
|
|
*
|
|
* xTimerReset() re-starts a timer that was previously created using the
|
|
* xTimerCreate() API function. If the timer had already been started and was
|
|
* already in the active state, then xTimerReset() will cause the timer to
|
|
* re-evaluate its expiry time so that it is relative to when xTimerReset() was
|
|
* called. If the timer was in the dormant state then xTimerReset() has
|
|
* equivalent functionality to the xTimerStart() API function.
|
|
*
|
|
* Resetting a timer ensures the timer is in the active state. If the timer
|
|
* is not stopped, deleted, or reset in the mean time, the callback function
|
|
* associated with the timer will get called 'n' ticks after xTimerReset() was
|
|
* called, where 'n' is the timers defined period.
|
|
*
|
|
* It is valid to call xTimerReset() before the scheduler has been started, but
|
|
* when this is done the timer will not actually start until the scheduler is
|
|
* started, and the timers expiry time will be relative to when the scheduler is
|
|
* started, not relative to when xTimerReset() was called.
|
|
*
|
|
* The configUSE_TIMERS configuration constant must be set to 1 for xTimerReset()
|
|
* to be available.
|
|
*
|
|
* @param xTimer The handle of the timer being reset/started/restarted.
|
|
*
|
|
* @param xTicksToWait Specifies the time, in ticks, that the calling task should
|
|
* be held in the Blocked state to wait for the reset command to be successfully
|
|
* sent to the timer command queue, should the queue already be full when
|
|
* xTimerReset() was called. xTicksToWait is ignored if xTimerReset() is called
|
|
* before the scheduler is started.
|
|
*
|
|
* @return pdFAIL will be returned if the reset command could not be sent to
|
|
* the timer command queue even after xTicksToWait ticks had passed. pdPASS will
|
|
* be returned if the command was successfully sent to the timer command queue.
|
|
* When the command is actually processed will depend on the priority of the
|
|
* timer service/daemon task relative to other tasks in the system, although the
|
|
* timers expiry time is relative to when xTimerStart() is actually called. The
|
|
* timer service/daemon task priority is set by the configTIMER_TASK_PRIORITY
|
|
* configuration constant.
|
|
*
|
|
* Example usage:
|
|
* @code{c}
|
|
* // When a key is pressed, an LCD back-light is switched on. If 5 seconds pass
|
|
* // without a key being pressed, then the LCD back-light is switched off. In
|
|
* // this case, the timer is a one-shot timer.
|
|
*
|
|
* TimerHandle_t xBacklightTimer = NULL;
|
|
*
|
|
* // The callback function assigned to the one-shot timer. In this case the
|
|
* // parameter is not used.
|
|
* void vBacklightTimerCallback( TimerHandle_t pxTimer )
|
|
* {
|
|
* // The timer expired, therefore 5 seconds must have passed since a key
|
|
* // was pressed. Switch off the LCD back-light.
|
|
* vSetBacklightState( BACKLIGHT_OFF );
|
|
* }
|
|
*
|
|
* // The key press event handler.
|
|
* void vKeyPressEventHandler( char cKey )
|
|
* {
|
|
* // Ensure the LCD back-light is on, then reset the timer that is
|
|
* // responsible for turning the back-light off after 5 seconds of
|
|
* // key inactivity. Wait 10 ticks for the command to be successfully sent
|
|
* // if it cannot be sent immediately.
|
|
* vSetBacklightState( BACKLIGHT_ON );
|
|
* if( xTimerReset( xBacklightTimer, 100 ) != pdPASS )
|
|
* {
|
|
* // The reset command was not executed successfully. Take appropriate
|
|
* // action here.
|
|
* }
|
|
*
|
|
* // Perform the rest of the key processing here.
|
|
* }
|
|
*
|
|
* void main( void )
|
|
* {
|
|
* int32_t x;
|
|
*
|
|
* // Create then start the one-shot timer that is responsible for turning
|
|
* // the back-light off if no keys are pressed within a 5 second period.
|
|
* xBacklightTimer = xTimerCreate( "BacklightTimer", // Just a text name, not used by the kernel.
|
|
* ( 5000 / portTICK_PERIOD_MS), // The timer period in ticks.
|
|
* pdFALSE, // The timer is a one-shot timer.
|
|
* 0, // The id is not used by the callback so can take any value.
|
|
* vBacklightTimerCallback // The callback function that switches the LCD back-light off.
|
|
* );
|
|
*
|
|
* if( xBacklightTimer == NULL )
|
|
* {
|
|
* // The timer was not created.
|
|
* }
|
|
* else
|
|
* {
|
|
* // Start the timer. No block time is specified, and even if one was
|
|
* // it would be ignored because the scheduler has not yet been
|
|
* // started.
|
|
* if( xTimerStart( xBacklightTimer, 0 ) != pdPASS )
|
|
* {
|
|
* // The timer could not be set into the Active state.
|
|
* }
|
|
* }
|
|
*
|
|
* // ...
|
|
* // Create tasks here.
|
|
* // ...
|
|
*
|
|
* // Starting the scheduler will start the timer running as it has already
|
|
* // been set into the active state.
|
|
* xTaskStartScheduler();
|
|
*
|
|
* // Should not reach here.
|
|
* for( ;; );
|
|
* }
|
|
* @endcode
|
|
*/
|
|
#define xTimerReset( xTimer, xTicksToWait ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_RESET, ( xTaskGetTickCount() ), NULL, ( xTicksToWait ) )
|
|
|
|
/**
|
|
* 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:
|
|
* @code{c}
|
|
* // This scenario assumes xBacklightTimer has already been created. When a
|
|
* // key is pressed, an LCD back-light is switched on. If 5 seconds pass
|
|
* // without a key being pressed, then the LCD back-light is switched off. In
|
|
* // this case, the timer is a one-shot timer, and unlike the example given for
|
|
* // the xTimerReset() function, the key press event handler is an interrupt
|
|
* // service routine.
|
|
*
|
|
* // The callback function assigned to the one-shot timer. In this case the
|
|
* // parameter is not used.
|
|
* void vBacklightTimerCallback( TimerHandle_t pxTimer )
|
|
* {
|
|
* // The timer expired, therefore 5 seconds must have passed since a key
|
|
* // was pressed. Switch off the LCD back-light.
|
|
* vSetBacklightState( BACKLIGHT_OFF );
|
|
* }
|
|
*
|
|
* // The key press interrupt service routine.
|
|
* void vKeyPressEventInterruptHandler( void )
|
|
* {
|
|
* BaseType_t xHigherPriorityTaskWoken = pdFALSE;
|
|
*
|
|
* // Ensure the LCD back-light is on, then restart the timer that is
|
|
* // responsible for turning the back-light off after 5 seconds of
|
|
* // key inactivity. This is an interrupt service routine so can only
|
|
* // call FreeRTOS API functions that end in "FromISR".
|
|
* vSetBacklightState( BACKLIGHT_ON );
|
|
*
|
|
* // xTimerStartFromISR() or xTimerResetFromISR() could be called here
|
|
* // as both cause the timer to re-calculate its expiry time.
|
|
* // xHigherPriorityTaskWoken was initialised to pdFALSE when it was
|
|
* // declared (in this function).
|
|
* if( xTimerStartFromISR( xBacklightTimer, &xHigherPriorityTaskWoken ) != pdPASS )
|
|
* {
|
|
* // The start command was not executed successfully. Take appropriate
|
|
* // action here.
|
|
* }
|
|
*
|
|
* // Perform the rest of the key processing here.
|
|
*
|
|
* // If xHigherPriorityTaskWoken equals pdTRUE, then a context switch
|
|
* // should be performed. The syntax required to perform a context switch
|
|
* // from inside an ISR varies from port to port, and from compiler to
|
|
* // compiler. Inspect the demos for the port you are using to find the
|
|
* // actual syntax required.
|
|
* if( xHigherPriorityTaskWoken != pdFALSE )
|
|
* {
|
|
* // Call the interrupt safe yield function here (actual function
|
|
* // depends on the FreeRTOS port being used).
|
|
* }
|
|
* }
|
|
* @endcode
|
|
*/
|
|
#define xTimerStartFromISR( xTimer, pxHigherPriorityTaskWoken ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_START_FROM_ISR, ( xTaskGetTickCountFromISR() ), ( pxHigherPriorityTaskWoken ), 0U )
|
|
|
|
/**
|
|
* 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:
|
|
* @code{c}
|
|
* // This scenario assumes xTimer has already been created and started. When
|
|
* // an interrupt occurs, the timer should be simply stopped.
|
|
*
|
|
* // The interrupt service routine that stops the timer.
|
|
* void vAnExampleInterruptServiceRoutine( void )
|
|
* {
|
|
* BaseType_t xHigherPriorityTaskWoken = pdFALSE;
|
|
*
|
|
* // The interrupt has occurred - simply stop the timer.
|
|
* // xHigherPriorityTaskWoken was set to pdFALSE where it was defined
|
|
* // (within this function). As this is an interrupt service routine, only
|
|
* // FreeRTOS API functions that end in "FromISR" can be used.
|
|
* if( xTimerStopFromISR( xTimer, &xHigherPriorityTaskWoken ) != pdPASS )
|
|
* {
|
|
* // The stop command was not executed successfully. Take appropriate
|
|
* // action here.
|
|
* }
|
|
*
|
|
* // If xHigherPriorityTaskWoken equals pdTRUE, then a context switch
|
|
* // should be performed. The syntax required to perform a context switch
|
|
* // from inside an ISR varies from port to port, and from compiler to
|
|
* // compiler. Inspect the demos for the port you are using to find the
|
|
* // actual syntax required.
|
|
* if( xHigherPriorityTaskWoken != pdFALSE )
|
|
* {
|
|
* // Call the interrupt safe yield function here (actual function
|
|
* // depends on the FreeRTOS port being used).
|
|
* }
|
|
* }
|
|
* @endcode
|
|
*/
|
|
#define xTimerStopFromISR( xTimer, pxHigherPriorityTaskWoken ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_STOP_FROM_ISR, 0, ( pxHigherPriorityTaskWoken ), 0U )
|
|
|
|
/**
|
|
* A version of xTimerChangePeriod() that can be called from an interrupt
|
|
* service routine.
|
|
*
|
|
* @param xTimer The handle of the timer that is having its period changed.
|
|
*
|
|
* @param xNewPeriod The new period for xTimer. Timer periods are specified in
|
|
* tick periods, so the constant portTICK_PERIOD_MS can be used to convert a time
|
|
* that has been specified in milliseconds. For example, if the timer must
|
|
* expire after 100 ticks, then xNewPeriod should be set to 100. Alternatively,
|
|
* if the timer must expire after 500ms, then xNewPeriod can be set to
|
|
* ( 500 / portTICK_PERIOD_MS ) provided configTICK_RATE_HZ is less than
|
|
* or equal to 1000.
|
|
*
|
|
* @param pxHigherPriorityTaskWoken The timer service/daemon task spends most
|
|
* of its time in the Blocked state, waiting for messages to arrive on the timer
|
|
* command queue. Calling xTimerChangePeriodFromISR() writes a message to the
|
|
* timer command queue, so has the potential to transition the timer service/
|
|
* daemon task out of the Blocked state. If calling xTimerChangePeriodFromISR()
|
|
* causes the timer service/daemon task to leave the Blocked state, and the
|
|
* timer service/daemon task has a priority equal to or greater than the
|
|
* currently executing task (the task that was interrupted), then
|
|
* *pxHigherPriorityTaskWoken will get set to pdTRUE internally within the
|
|
* xTimerChangePeriodFromISR() function. If xTimerChangePeriodFromISR() sets
|
|
* this value to pdTRUE then a context switch should be performed before the
|
|
* interrupt exits.
|
|
*
|
|
* @return pdFAIL will be returned if the command to change the timers period
|
|
* could not be sent to the timer command queue. pdPASS will be returned if the
|
|
* command was successfully sent to the timer command queue. When the command
|
|
* is actually processed will depend on the priority of the timer service/daemon
|
|
* task relative to other tasks in the system. The timer service/daemon task
|
|
* priority is set by the configTIMER_TASK_PRIORITY configuration constant.
|
|
*
|
|
* Example usage:
|
|
* @code{c}
|
|
* // This scenario assumes xTimer has already been created and started. When
|
|
* // an interrupt occurs, the period of xTimer should be changed to 500ms.
|
|
*
|
|
* // The interrupt service routine that changes the period of xTimer.
|
|
* void vAnExampleInterruptServiceRoutine( void )
|
|
* {
|
|
* BaseType_t xHigherPriorityTaskWoken = pdFALSE;
|
|
*
|
|
* // The interrupt has occurred - change the period of xTimer to 500ms.
|
|
* // xHigherPriorityTaskWoken was set to pdFALSE where it was defined
|
|
* // (within this function). As this is an interrupt service routine, only
|
|
* // FreeRTOS API functions that end in "FromISR" can be used.
|
|
* if( xTimerChangePeriodFromISR( xTimer, &xHigherPriorityTaskWoken ) != pdPASS )
|
|
* {
|
|
* // The command to change the timers period was not executed
|
|
* // successfully. Take appropriate action here.
|
|
* }
|
|
*
|
|
* // If xHigherPriorityTaskWoken equals pdTRUE, then a context switch
|
|
* // should be performed. The syntax required to perform a context switch
|
|
* // from inside an ISR varies from port to port, and from compiler to
|
|
* // compiler. Inspect the demos for the port you are using to find the
|
|
* // actual syntax required.
|
|
* if( xHigherPriorityTaskWoken != pdFALSE )
|
|
* {
|
|
* // Call the interrupt safe yield function here (actual function
|
|
* // depends on the FreeRTOS port being used).
|
|
* }
|
|
* }
|
|
* @endcode
|
|
*/
|
|
#define xTimerChangePeriodFromISR( xTimer, xNewPeriod, pxHigherPriorityTaskWoken ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_CHANGE_PERIOD_FROM_ISR, ( xNewPeriod ), ( pxHigherPriorityTaskWoken ), 0U )
|
|
|
|
/**
|
|
* 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:
|
|
* @code{c}
|
|
* // This scenario assumes xBacklightTimer has already been created. When a
|
|
* // key is pressed, an LCD back-light is switched on. If 5 seconds pass
|
|
* // without a key being pressed, then the LCD back-light is switched off. In
|
|
* // this case, the timer is a one-shot timer, and unlike the example given for
|
|
* // the xTimerReset() function, the key press event handler is an interrupt
|
|
* // service routine.
|
|
*
|
|
* // The callback function assigned to the one-shot timer. In this case the
|
|
* // parameter is not used.
|
|
* void vBacklightTimerCallback( TimerHandle_t pxTimer )
|
|
* {
|
|
* // The timer expired, therefore 5 seconds must have passed since a key
|
|
* // was pressed. Switch off the LCD back-light.
|
|
* vSetBacklightState( BACKLIGHT_OFF );
|
|
* }
|
|
*
|
|
* // The key press interrupt service routine.
|
|
* void vKeyPressEventInterruptHandler( void )
|
|
* {
|
|
* BaseType_t xHigherPriorityTaskWoken = pdFALSE;
|
|
*
|
|
* // Ensure the LCD back-light is on, then reset the timer that is
|
|
* // responsible for turning the back-light off after 5 seconds of
|
|
* // key inactivity. This is an interrupt service routine so can only
|
|
* // call FreeRTOS API functions that end in "FromISR".
|
|
* vSetBacklightState( BACKLIGHT_ON );
|
|
*
|
|
* // xTimerStartFromISR() or xTimerResetFromISR() could be called here
|
|
* // as both cause the timer to re-calculate its expiry time.
|
|
* // xHigherPriorityTaskWoken was initialised to pdFALSE when it was
|
|
* // declared (in this function).
|
|
* if( xTimerResetFromISR( xBacklightTimer, &xHigherPriorityTaskWoken ) != pdPASS )
|
|
* {
|
|
* // The reset command was not executed successfully. Take appropriate
|
|
* // action here.
|
|
* }
|
|
*
|
|
* // Perform the rest of the key processing here.
|
|
*
|
|
* // If xHigherPriorityTaskWoken equals pdTRUE, then a context switch
|
|
* // should be performed. The syntax required to perform a context switch
|
|
* // from inside an ISR varies from port to port, and from compiler to
|
|
* // compiler. Inspect the demos for the port you are using to find the
|
|
* // actual syntax required.
|
|
* if( xHigherPriorityTaskWoken != pdFALSE )
|
|
* {
|
|
* // Call the interrupt safe yield function here (actual function
|
|
* // depends on the FreeRTOS port being used).
|
|
* }
|
|
* }
|
|
* @endcode
|
|
*/
|
|
#define xTimerResetFromISR( xTimer, pxHigherPriorityTaskWoken ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_RESET_FROM_ISR, ( xTaskGetTickCountFromISR() ), ( pxHigherPriorityTaskWoken ), 0U )
|
|
|
|
|
|
/**
|
|
* Used from application interrupt service routines to defer the execution of a
|
|
* function to the RTOS daemon task (the timer service task, hence this function
|
|
* is implemented in timers.c and is prefixed with 'Timer').
|
|
*
|
|
* Ideally an interrupt service routine (ISR) is kept as short as possible, but
|
|
* sometimes an ISR either has a lot of processing to do, or needs to perform
|
|
* processing that is not deterministic. In these cases
|
|
* xTimerPendFunctionCallFromISR() can be used to defer processing of a function
|
|
* to the RTOS daemon task.
|
|
*
|
|
* A mechanism is provided that allows the interrupt to return directly to the
|
|
* task that will subsequently execute the pended callback function. This
|
|
* allows the callback function to execute contiguously in time with the
|
|
* interrupt - just as if the callback had executed in the interrupt itself.
|
|
*
|
|
* @param xFunctionToPend The function to execute from the timer service/
|
|
* daemon task. The function must conform to the PendedFunction_t
|
|
* prototype.
|
|
*
|
|
* @param pvParameter1 The value of the callback function's first parameter.
|
|
* The parameter has a void * type to allow it to be used to pass any type.
|
|
* For example, unsigned longs can be cast to a void *, or the void * can be
|
|
* used to point to a structure.
|
|
*
|
|
* @param ulParameter2 The value of the callback function's second parameter.
|
|
*
|
|
* @param pxHigherPriorityTaskWoken As mentioned above, calling this function
|
|
* will result in a message being sent to the timer daemon task. If the
|
|
* priority of the timer daemon task (which is set using
|
|
* configTIMER_TASK_PRIORITY in FreeRTOSConfig.h) is higher than the priority of
|
|
* the currently running task (the task the interrupt interrupted) then
|
|
* *pxHigherPriorityTaskWoken will be set to pdTRUE within
|
|
* xTimerPendFunctionCallFromISR(), indicating that a context switch should be
|
|
* requested before the interrupt exits. For that reason
|
|
* *pxHigherPriorityTaskWoken must be initialised to pdFALSE. See the
|
|
* example code below.
|
|
*
|
|
* @return pdPASS is returned if the message was successfully sent to the
|
|
* timer daemon task, otherwise pdFALSE is returned.
|
|
*
|
|
* Example usage:
|
|
* @code{c}
|
|
*
|
|
* // The callback function that will execute in the context of the daemon task.
|
|
* // Note callback functions must all use this same prototype.
|
|
* void vProcessInterface( void *pvParameter1, uint32_t ulParameter2 )
|
|
* {
|
|
* BaseType_t xInterfaceToService;
|
|
*
|
|
* // The interface that requires servicing is passed in the second
|
|
* // parameter. The first parameter is not used in this case.
|
|
* xInterfaceToService = ( BaseType_t ) ulParameter2;
|
|
*
|
|
* // ...Perform the processing here...
|
|
* }
|
|
*
|
|
* // An ISR that receives data packets from multiple interfaces
|
|
* void vAnISR( void )
|
|
* {
|
|
* BaseType_t xInterfaceToService, xHigherPriorityTaskWoken;
|
|
*
|
|
* // Query the hardware to determine which interface needs processing.
|
|
* xInterfaceToService = prvCheckInterfaces();
|
|
*
|
|
* // The actual processing is to be deferred to a task. Request the
|
|
* // vProcessInterface() callback function is executed, passing in the
|
|
* // number of the interface that needs processing. The interface to
|
|
* // service is passed in the second parameter. The first parameter is
|
|
* // not used in this case.
|
|
* xHigherPriorityTaskWoken = pdFALSE;
|
|
* xTimerPendFunctionCallFromISR( vProcessInterface, NULL, ( uint32_t ) xInterfaceToService, &xHigherPriorityTaskWoken );
|
|
*
|
|
* // If xHigherPriorityTaskWoken is now set to pdTRUE then a context
|
|
* // switch should be requested. The macro used is port specific and will
|
|
* // be either portYIELD_FROM_ISR() or portEND_SWITCHING_ISR() - refer to
|
|
* // the documentation page for the port being used.
|
|
* portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
|
|
*
|
|
* }
|
|
* @endcode
|
|
*/
|
|
BaseType_t xTimerPendFunctionCallFromISR( PendedFunction_t xFunctionToPend, void *pvParameter1, uint32_t ulParameter2, BaseType_t *pxHigherPriorityTaskWoken );
|
|
|
|
/**
|
|
* Used to defer the execution of a function to the RTOS daemon task (the timer
|
|
* service task, hence this function is implemented in timers.c and is prefixed
|
|
* with 'Timer').
|
|
*
|
|
* @param xFunctionToPend The function to execute from the timer service/
|
|
* daemon task. The function must conform to the PendedFunction_t
|
|
* prototype.
|
|
*
|
|
* @param pvParameter1 The value of the callback function's first parameter.
|
|
* The parameter has a void * type to allow it to be used to pass any type.
|
|
* For example, unsigned longs can be cast to a void *, or the void * can be
|
|
* used to point to a structure.
|
|
*
|
|
* @param ulParameter2 The value of the callback function's second parameter.
|
|
*
|
|
* @param xTicksToWait Calling this function will result in a message being
|
|
* sent to the timer daemon task on a queue. xTicksToWait is the amount of
|
|
* time the calling task should remain in the Blocked state (so not using any
|
|
* processing time) for space to become available on the timer queue if the
|
|
* queue is found to be full.
|
|
*
|
|
* @return pdPASS is returned if the message was successfully sent to the
|
|
* timer daemon task, otherwise pdFALSE is returned.
|
|
*
|
|
*/
|
|
BaseType_t xTimerPendFunctionCall( PendedFunction_t xFunctionToPend, void *pvParameter1, uint32_t ulParameter2, TickType_t xTicksToWait );
|
|
|
|
/**
|
|
* Returns the name that was assigned to a timer when the timer was created.
|
|
*
|
|
* @param xTimer The handle of the timer being queried.
|
|
*
|
|
* @return The name assigned to the timer specified by the xTimer parameter.
|
|
*/
|
|
const char * pcTimerGetTimerName( TimerHandle_t xTimer ); /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
|
|
|
|
/** @cond */
|
|
/*
|
|
* Functions beyond this part are not part of the public API and are intended
|
|
* for use by the kernel only.
|
|
*/
|
|
BaseType_t xTimerCreateTimerTask( void ) PRIVILEGED_FUNCTION;
|
|
BaseType_t xTimerGenericCommand( TimerHandle_t xTimer, const BaseType_t xCommandID, const TickType_t xOptionalValue, BaseType_t * const pxHigherPriorityTaskWoken, const TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
|
|
|
|
/** @endcond */
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
#endif /* TIMERS_H */
|
|
|
|
|
|
|