727 lines
28 KiB
C
727 lines
28 KiB
C
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/*
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FreeRTOS V8.1.2 - Copyright (C) 2014 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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***************************************************************************
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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 has become a de facto standard. *
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* *
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* Help yourself get started quickly and support the FreeRTOS *
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* project by purchasing a FreeRTOS tutorial book, reference *
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* manual, or both from: http://www.FreeRTOS.org/Documentation *
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* *
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* Thank you! *
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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 !<<
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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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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 from the following
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link: http://www.freertos.org/a00114.html
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1 tab == 4 spaces!
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***************************************************************************
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* *
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* Having a problem? Start by reading the FAQ "My application does *
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* not run, what could be wrong?" *
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* *
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* http://www.FreeRTOS.org/FAQHelp.html *
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* *
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***************************************************************************
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http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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license and Real Time Engineers Ltd. contact details.
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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.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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licenses offer ticketed support, indemnification and 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 EVENT_GROUPS_H
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#define EVENT_GROUPS_H
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#ifndef INC_FREERTOS_H
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#error "include FreeRTOS.h" must appear in source files before "include event_groups.h"
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#endif
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#include "timers.h"
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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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* An event group is a collection of bits to which an application can assign a
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* meaning. For example, an application may create an event group to convey
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* the status of various CAN bus related events in which bit 0 might mean "A CAN
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* message has been received and is ready for processing", bit 1 might mean "The
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* application has queued a message that is ready for sending onto the CAN
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* network", and bit 2 might mean "It is time to send a SYNC message onto the
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* CAN network" etc. A task can then test the bit values to see which events
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* are active, and optionally enter the Blocked state to wait for a specified
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* bit or a group of specified bits to be active. To continue the CAN bus
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* example, a CAN controlling task can enter the Blocked state (and therefore
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* not consume any processing time) until either bit 0, bit 1 or bit 2 are
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* active, at which time the bit that was actually active would inform the task
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* which action it had to take (process a received message, send a message, or
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* send a SYNC).
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*
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* The event groups implementation contains intelligence to avoid race
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* conditions that would otherwise occur were an application to use a simple
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* variable for the same purpose. This is particularly important with respect
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* to when a bit within an event group is to be cleared, and when bits have to
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* be set and then tested atomically - as is the case where event groups are
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* used to create a synchronisation point between multiple tasks (a
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* 'rendezvous').
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*
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* \defgroup EventGroup
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*/
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/**
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* event_groups.h
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*
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* Type by which event groups are referenced. For example, a call to
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* xEventGroupCreate() returns an EventGroupHandle_t variable that can then
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* be used as a parameter to other event group functions.
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*
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* \defgroup EventGroupHandle_t EventGroupHandle_t
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* \ingroup EventGroup
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*/
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typedef void * EventGroupHandle_t;
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/*
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* The type that holds event bits always matches TickType_t - therefore the
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* number of bits it holds is set by configUSE_16_BIT_TICKS (16 bits if set to 1,
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* 32 bits if set to 0.
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*
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* \defgroup EventBits_t EventBits_t
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* \ingroup EventGroup
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*/
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typedef TickType_t EventBits_t;
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/**
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* event_groups.h
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*<pre>
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EventGroupHandle_t xEventGroupCreate( void );
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</pre>
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*
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* Create a new event group. This function cannot be called from an interrupt.
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*
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* Although event groups are not related to ticks, for internal implementation
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* reasons the number of bits available for use in an event group is dependent
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* on the configUSE_16_BIT_TICKS setting in FreeRTOSConfig.h. If
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* configUSE_16_BIT_TICKS is 1 then each event group contains 8 usable bits (bit
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* 0 to bit 7). If configUSE_16_BIT_TICKS is set to 0 then each event group has
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* 24 usable bits (bit 0 to bit 23). The EventBits_t type is used to store
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* event bits within an event group.
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*
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* @return If the event group was created then a handle to the event group is
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* returned. If there was insufficient FreeRTOS heap available to create the
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* event group then NULL is returned. See http://www.freertos.org/a00111.html
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*
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* Example usage:
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<pre>
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// Declare a variable to hold the created event group.
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EventGroupHandle_t xCreatedEventGroup;
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// Attempt to create the event group.
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xCreatedEventGroup = xEventGroupCreate();
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// Was the event group created successfully?
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if( xCreatedEventGroup == NULL )
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{
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// The event group was not created because there was insufficient
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// FreeRTOS heap available.
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}
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else
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{
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// The event group was created.
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}
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</pre>
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* \defgroup xEventGroupCreate xEventGroupCreate
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* \ingroup EventGroup
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*/
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EventGroupHandle_t xEventGroupCreate( void ) PRIVILEGED_FUNCTION;
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/**
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* event_groups.h
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*<pre>
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EventBits_t xEventGroupWaitBits( EventGroupHandle_t xEventGroup,
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const EventBits_t uxBitsToWaitFor,
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const BaseType_t xClearOnExit,
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const BaseType_t xWaitForAllBits,
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const TickType_t xTicksToWait );
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</pre>
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*
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* [Potentially] block to wait for one or more bits to be set within a
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* previously created event group.
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*
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* This function cannot be called from an interrupt.
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*
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* @param xEventGroup The event group in which the bits are being tested. The
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* event group must have previously been created using a call to
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* xEventGroupCreate().
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*
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* @param uxBitsToWaitFor A bitwise value that indicates the bit or bits to test
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* inside the event group. For example, to wait for bit 0 and/or bit 2 set
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* uxBitsToWaitFor to 0x05. To wait for bits 0 and/or bit 1 and/or bit 2 set
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* uxBitsToWaitFor to 0x07. Etc.
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*
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* @param xClearOnExit If xClearOnExit is set to pdTRUE then any bits within
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* uxBitsToWaitFor that are set within the event group will be cleared before
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* xEventGroupWaitBits() returns if the wait condition was met (if the function
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* returns for a reason other than a timeout). If xClearOnExit is set to
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* pdFALSE then the bits set in the event group are not altered when the call to
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* xEventGroupWaitBits() returns.
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*
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* @param xWaitForAllBits If xWaitForAllBits is set to pdTRUE then
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* xEventGroupWaitBits() will return when either all the bits in uxBitsToWaitFor
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* are set or the specified block time expires. If xWaitForAllBits is set to
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* pdFALSE then xEventGroupWaitBits() will return when any one of the bits set
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* in uxBitsToWaitFor is set or the specified block time expires. The block
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* time is specified by the xTicksToWait parameter.
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*
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* @param xTicksToWait The maximum amount of time (specified in 'ticks') to wait
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* for one/all (depending on the xWaitForAllBits value) of the bits specified by
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* uxBitsToWaitFor to become set.
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*
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* @return The value of the event group at the time either the bits being waited
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* for became set, or the block time expired. Test the return value to know
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* which bits were set. If xEventGroupWaitBits() returned because its timeout
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* expired then not all the bits being waited for will be set. If
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* xEventGroupWaitBits() returned because the bits it was waiting for were set
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* then the returned value is the event group value before any bits were
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* automatically cleared in the case that xClearOnExit parameter was set to
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* pdTRUE.
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*
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* Example usage:
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<pre>
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#define BIT_0 ( 1 << 0 )
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#define BIT_4 ( 1 << 4 )
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void aFunction( EventGroupHandle_t xEventGroup )
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{
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EventBits_t uxBits;
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const TickType_t xTicksToWait = 100 / portTICK_PERIOD_MS;
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// Wait a maximum of 100ms for either bit 0 or bit 4 to be set within
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// the event group. Clear the bits before exiting.
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uxBits = xEventGroupWaitBits(
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xEventGroup, // The event group being tested.
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BIT_0 | BIT_4, // The bits within the event group to wait for.
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pdTRUE, // BIT_0 and BIT_4 should be cleared before returning.
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pdFALSE, // Don't wait for both bits, either bit will do.
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xTicksToWait ); // Wait a maximum of 100ms for either bit to be set.
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if( ( uxBits & ( BIT_0 | BIT_4 ) ) == ( BIT_0 | BIT_4 ) )
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{
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// xEventGroupWaitBits() returned because both bits were set.
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}
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else if( ( uxBits & BIT_0 ) != 0 )
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{
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// xEventGroupWaitBits() returned because just BIT_0 was set.
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}
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else if( ( uxBits & BIT_4 ) != 0 )
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{
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// xEventGroupWaitBits() returned because just BIT_4 was set.
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}
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else
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{
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// xEventGroupWaitBits() returned because xTicksToWait ticks passed
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// without either BIT_0 or BIT_4 becoming set.
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}
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}
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</pre>
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* \defgroup xEventGroupWaitBits xEventGroupWaitBits
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* \ingroup EventGroup
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*/
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EventBits_t xEventGroupWaitBits( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToWaitFor, const BaseType_t xClearOnExit, const BaseType_t xWaitForAllBits, TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
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/**
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* event_groups.h
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*<pre>
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EventBits_t xEventGroupClearBits( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToClear );
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</pre>
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*
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* Clear bits within an event group. This function cannot be called from an
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* interrupt.
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*
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* @param xEventGroup The event group in which the bits are to be cleared.
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*
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* @param uxBitsToClear A bitwise value that indicates the bit or bits to clear
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* in the event group. For example, to clear bit 3 only, set uxBitsToClear to
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* 0x08. To clear bit 3 and bit 0 set uxBitsToClear to 0x09.
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*
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* @return The value of the event group before the specified bits were cleared.
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*
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* Example usage:
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<pre>
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#define BIT_0 ( 1 << 0 )
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#define BIT_4 ( 1 << 4 )
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void aFunction( EventGroupHandle_t xEventGroup )
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{
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EventBits_t uxBits;
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// Clear bit 0 and bit 4 in xEventGroup.
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uxBits = xEventGroupClearBits(
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xEventGroup, // The event group being updated.
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BIT_0 | BIT_4 );// The bits being cleared.
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if( ( uxBits & ( BIT_0 | BIT_4 ) ) == ( BIT_0 | BIT_4 ) )
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{
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// Both bit 0 and bit 4 were set before xEventGroupClearBits() was
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// called. Both will now be clear (not set).
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}
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else if( ( uxBits & BIT_0 ) != 0 )
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{
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// Bit 0 was set before xEventGroupClearBits() was called. It will
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// now be clear.
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}
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else if( ( uxBits & BIT_4 ) != 0 )
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{
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// Bit 4 was set before xEventGroupClearBits() was called. It will
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// now be clear.
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}
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else
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{
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// Neither bit 0 nor bit 4 were set in the first place.
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}
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}
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</pre>
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* \defgroup xEventGroupClearBits xEventGroupClearBits
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* \ingroup EventGroup
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*/
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EventBits_t xEventGroupClearBits( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToClear ) PRIVILEGED_FUNCTION;
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/**
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* event_groups.h
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*<pre>
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BaseType_t xEventGroupClearBitsFromISR( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet );
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</pre>
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*
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* A version of xEventGroupClearBits() that can be called from an interrupt.
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*
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* Setting bits in an event group is not a deterministic operation because there
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* are an unknown number of tasks that may be waiting for the bit or bits being
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* set. FreeRTOS does not allow nondeterministic operations to be performed
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* while interrupts are disabled, so protects event groups that are accessed
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* from tasks by suspending the scheduler rather than disabling interrupts. As
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* a result event groups cannot be accessed directly from an interrupt service
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* routine. Therefore xEventGroupClearBitsFromISR() sends a message to the
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* timer task to have the clear operation performed in the context of the timer
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* task.
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*
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* @param xEventGroup The event group in which the bits are to be cleared.
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*
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* @param uxBitsToClear A bitwise value that indicates the bit or bits to clear.
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* For example, to clear bit 3 only, set uxBitsToClear to 0x08. To clear bit 3
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* and bit 0 set uxBitsToClear to 0x09.
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*
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* @return If the request to execute the function was posted successfully then
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|
|
* pdPASS is returned, otherwise pdFALSE is returned. pdFALSE will be returned
|
||
|
|
* if the timer service queue was full.
|
||
|
|
*
|
||
|
|
* Example usage:
|
||
|
|
<pre>
|
||
|
|
#define BIT_0 ( 1 << 0 )
|
||
|
|
#define BIT_4 ( 1 << 4 )
|
||
|
|
|
||
|
|
// An event group which it is assumed has already been created by a call to
|
||
|
|
// xEventGroupCreate().
|
||
|
|
EventGroupHandle_t xEventGroup;
|
||
|
|
|
||
|
|
void anInterruptHandler( void )
|
||
|
|
{
|
||
|
|
// Clear bit 0 and bit 4 in xEventGroup.
|
||
|
|
xResult = xEventGroupClearBitsFromISR(
|
||
|
|
xEventGroup, // The event group being updated.
|
||
|
|
BIT_0 | BIT_4 ); // The bits being set.
|
||
|
|
|
||
|
|
if( xResult == pdPASS )
|
||
|
|
{
|
||
|
|
// The message was posted successfully.
|
||
|
|
}
|
||
|
|
}
|
||
|
|
</pre>
|
||
|
|
* \defgroup xEventGroupSetBitsFromISR xEventGroupSetBitsFromISR
|
||
|
|
* \ingroup EventGroup
|
||
|
|
*/
|
||
|
|
#if( configUSE_TRACE_FACILITY == 1 )
|
||
|
|
BaseType_t xEventGroupClearBitsFromISR( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet );
|
||
|
|
#else
|
||
|
|
#define xEventGroupClearBitsFromISR( xEventGroup, uxBitsToClear ) xTimerPendFunctionCallFromISR( vEventGroupClearBitsCallback, ( void * ) xEventGroup, ( uint32_t ) uxBitsToClear, NULL )
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/**
|
||
|
|
* event_groups.h
|
||
|
|
*<pre>
|
||
|
|
EventBits_t xEventGroupSetBits( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet );
|
||
|
|
</pre>
|
||
|
|
*
|
||
|
|
* Set bits within an event group.
|
||
|
|
* This function cannot be called from an interrupt. xEventGroupSetBitsFromISR()
|
||
|
|
* is a version that can be called from an interrupt.
|
||
|
|
*
|
||
|
|
* Setting bits in an event group will automatically unblock tasks that are
|
||
|
|
* blocked waiting for the bits.
|
||
|
|
*
|
||
|
|
* @param xEventGroup The event group in which the bits are to be set.
|
||
|
|
*
|
||
|
|
* @param uxBitsToSet A bitwise value that indicates the bit or bits to set.
|
||
|
|
* For example, to set bit 3 only, set uxBitsToSet to 0x08. To set bit 3
|
||
|
|
* and bit 0 set uxBitsToSet to 0x09.
|
||
|
|
*
|
||
|
|
* @return The value of the event group at the time the call to
|
||
|
|
* xEventGroupSetBits() returns. There are two reasons why the returned value
|
||
|
|
* might have the bits specified by the uxBitsToSet parameter cleared. First,
|
||
|
|
* if setting a bit results in a task that was waiting for the bit leaving the
|
||
|
|
* blocked state then it is possible the bit will be cleared automatically
|
||
|
|
* (see the xClearBitOnExit parameter of xEventGroupWaitBits()). Second, any
|
||
|
|
* unblocked (or otherwise Ready state) task that has a priority above that of
|
||
|
|
* the task that called xEventGroupSetBits() will execute and may change the
|
||
|
|
* event group value before the call to xEventGroupSetBits() returns.
|
||
|
|
*
|
||
|
|
* Example usage:
|
||
|
|
<pre>
|
||
|
|
#define BIT_0 ( 1 << 0 )
|
||
|
|
#define BIT_4 ( 1 << 4 )
|
||
|
|
|
||
|
|
void aFunction( EventGroupHandle_t xEventGroup )
|
||
|
|
{
|
||
|
|
EventBits_t uxBits;
|
||
|
|
|
||
|
|
// Set bit 0 and bit 4 in xEventGroup.
|
||
|
|
uxBits = xEventGroupSetBits(
|
||
|
|
xEventGroup, // The event group being updated.
|
||
|
|
BIT_0 | BIT_4 );// The bits being set.
|
||
|
|
|
||
|
|
if( ( uxBits & ( BIT_0 | BIT_4 ) ) == ( BIT_0 | BIT_4 ) )
|
||
|
|
{
|
||
|
|
// Both bit 0 and bit 4 remained set when the function returned.
|
||
|
|
}
|
||
|
|
else if( ( uxBits & BIT_0 ) != 0 )
|
||
|
|
{
|
||
|
|
// Bit 0 remained set when the function returned, but bit 4 was
|
||
|
|
// cleared. It might be that bit 4 was cleared automatically as a
|
||
|
|
// task that was waiting for bit 4 was removed from the Blocked
|
||
|
|
// state.
|
||
|
|
}
|
||
|
|
else if( ( uxBits & BIT_4 ) != 0 )
|
||
|
|
{
|
||
|
|
// Bit 4 remained set when the function returned, but bit 0 was
|
||
|
|
// cleared. It might be that bit 0 was cleared automatically as a
|
||
|
|
// task that was waiting for bit 0 was removed from the Blocked
|
||
|
|
// state.
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
// Neither bit 0 nor bit 4 remained set. It might be that a task
|
||
|
|
// was waiting for both of the bits to be set, and the bits were
|
||
|
|
// cleared as the task left the Blocked state.
|
||
|
|
}
|
||
|
|
}
|
||
|
|
</pre>
|
||
|
|
* \defgroup xEventGroupSetBits xEventGroupSetBits
|
||
|
|
* \ingroup EventGroup
|
||
|
|
*/
|
||
|
|
EventBits_t xEventGroupSetBits( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet ) PRIVILEGED_FUNCTION;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* event_groups.h
|
||
|
|
*<pre>
|
||
|
|
BaseType_t xEventGroupSetBitsFromISR( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet, BaseType_t *pxHigherPriorityTaskWoken );
|
||
|
|
</pre>
|
||
|
|
*
|
||
|
|
* A version of xEventGroupSetBits() that can be called from an interrupt.
|
||
|
|
*
|
||
|
|
* Setting bits in an event group is not a deterministic operation because there
|
||
|
|
* are an unknown number of tasks that may be waiting for the bit or bits being
|
||
|
|
* set. FreeRTOS does not allow nondeterministic operations to be performed in
|
||
|
|
* interrupts or from critical sections. Therefore xEventGroupSetBitFromISR()
|
||
|
|
* sends a message to the timer task to have the set operation performed in the
|
||
|
|
* context of the timer task - where a scheduler lock is used in place of a
|
||
|
|
* critical section.
|
||
|
|
*
|
||
|
|
* @param xEventGroup The event group in which the bits are to be set.
|
||
|
|
*
|
||
|
|
* @param uxBitsToSet A bitwise value that indicates the bit or bits to set.
|
||
|
|
* For example, to set bit 3 only, set uxBitsToSet to 0x08. To set bit 3
|
||
|
|
* and bit 0 set uxBitsToSet to 0x09.
|
||
|
|
*
|
||
|
|
* @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 is higher than the priority of the
|
||
|
|
* currently running task (the task the interrupt interrupted) then
|
||
|
|
* *pxHigherPriorityTaskWoken will be set to pdTRUE by
|
||
|
|
* xEventGroupSetBitsFromISR(), 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 If the request to execute the function was posted successfully then
|
||
|
|
* pdPASS is returned, otherwise pdFALSE is returned. pdFALSE will be returned
|
||
|
|
* if the timer service queue was full.
|
||
|
|
*
|
||
|
|
* Example usage:
|
||
|
|
<pre>
|
||
|
|
#define BIT_0 ( 1 << 0 )
|
||
|
|
#define BIT_4 ( 1 << 4 )
|
||
|
|
|
||
|
|
// An event group which it is assumed has already been created by a call to
|
||
|
|
// xEventGroupCreate().
|
||
|
|
EventGroupHandle_t xEventGroup;
|
||
|
|
|
||
|
|
void anInterruptHandler( void )
|
||
|
|
{
|
||
|
|
BaseType_t xHigherPriorityTaskWoken, xResult;
|
||
|
|
|
||
|
|
// xHigherPriorityTaskWoken must be initialised to pdFALSE.
|
||
|
|
xHigherPriorityTaskWoken = pdFALSE;
|
||
|
|
|
||
|
|
// Set bit 0 and bit 4 in xEventGroup.
|
||
|
|
xResult = xEventGroupSetBitsFromISR(
|
||
|
|
xEventGroup, // The event group being updated.
|
||
|
|
BIT_0 | BIT_4 // The bits being set.
|
||
|
|
&xHigherPriorityTaskWoken );
|
||
|
|
|
||
|
|
// Was the message posted successfully?
|
||
|
|
if( xResult == pdPASS )
|
||
|
|
{
|
||
|
|
// 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 );
|
||
|
|
}
|
||
|
|
}
|
||
|
|
</pre>
|
||
|
|
* \defgroup xEventGroupSetBitsFromISR xEventGroupSetBitsFromISR
|
||
|
|
* \ingroup EventGroup
|
||
|
|
*/
|
||
|
|
#if( configUSE_TRACE_FACILITY == 1 )
|
||
|
|
BaseType_t xEventGroupSetBitsFromISR( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet, BaseType_t *pxHigherPriorityTaskWoken );
|
||
|
|
#else
|
||
|
|
#define xEventGroupSetBitsFromISR( xEventGroup, uxBitsToSet, pxHigherPriorityTaskWoken ) xTimerPendFunctionCallFromISR( vEventGroupSetBitsCallback, ( void * ) xEventGroup, ( uint32_t ) uxBitsToSet, pxHigherPriorityTaskWoken )
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/**
|
||
|
|
* event_groups.h
|
||
|
|
*<pre>
|
||
|
|
EventBits_t xEventGroupSync( EventGroupHandle_t xEventGroup,
|
||
|
|
const EventBits_t uxBitsToSet,
|
||
|
|
const EventBits_t uxBitsToWaitFor,
|
||
|
|
TickType_t xTicksToWait );
|
||
|
|
</pre>
|
||
|
|
*
|
||
|
|
* Atomically set bits within an event group, then wait for a combination of
|
||
|
|
* bits to be set within the same event group. This functionality is typically
|
||
|
|
* used to synchronise multiple tasks, where each task has to wait for the other
|
||
|
|
* tasks to reach a synchronisation point before proceeding.
|
||
|
|
*
|
||
|
|
* This function cannot be used from an interrupt.
|
||
|
|
*
|
||
|
|
* The function will return before its block time expires if the bits specified
|
||
|
|
* by the uxBitsToWait parameter are set, or become set within that time. In
|
||
|
|
* this case all the bits specified by uxBitsToWait will be automatically
|
||
|
|
* cleared before the function returns.
|
||
|
|
*
|
||
|
|
* @param xEventGroup The event group in which the bits are being tested. The
|
||
|
|
* event group must have previously been created using a call to
|
||
|
|
* xEventGroupCreate().
|
||
|
|
*
|
||
|
|
* @param uxBitsToSet The bits to set in the event group before determining
|
||
|
|
* if, and possibly waiting for, all the bits specified by the uxBitsToWait
|
||
|
|
* parameter are set.
|
||
|
|
*
|
||
|
|
* @param uxBitsToWaitFor A bitwise value that indicates the bit or bits to test
|
||
|
|
* inside the event group. For example, to wait for bit 0 and bit 2 set
|
||
|
|
* uxBitsToWaitFor to 0x05. To wait for bits 0 and bit 1 and bit 2 set
|
||
|
|
* uxBitsToWaitFor to 0x07. Etc.
|
||
|
|
*
|
||
|
|
* @param xTicksToWait The maximum amount of time (specified in 'ticks') to wait
|
||
|
|
* for all of the bits specified by uxBitsToWaitFor to become set.
|
||
|
|
*
|
||
|
|
* @return The value of the event group at the time either the bits being waited
|
||
|
|
* for became set, or the block time expired. Test the return value to know
|
||
|
|
* which bits were set. If xEventGroupSync() returned because its timeout
|
||
|
|
* expired then not all the bits being waited for will be set. If
|
||
|
|
* xEventGroupSync() returned because all the bits it was waiting for were
|
||
|
|
* set then the returned value is the event group value before any bits were
|
||
|
|
* automatically cleared.
|
||
|
|
*
|
||
|
|
* Example usage:
|
||
|
|
<pre>
|
||
|
|
// Bits used by the three tasks.
|
||
|
|
#define TASK_0_BIT ( 1 << 0 )
|
||
|
|
#define TASK_1_BIT ( 1 << 1 )
|
||
|
|
#define TASK_2_BIT ( 1 << 2 )
|
||
|
|
|
||
|
|
#define ALL_SYNC_BITS ( TASK_0_BIT | TASK_1_BIT | TASK_2_BIT )
|
||
|
|
|
||
|
|
// Use an event group to synchronise three tasks. It is assumed this event
|
||
|
|
// group has already been created elsewhere.
|
||
|
|
EventGroupHandle_t xEventBits;
|
||
|
|
|
||
|
|
void vTask0( void *pvParameters )
|
||
|
|
{
|
||
|
|
EventBits_t uxReturn;
|
||
|
|
TickType_t xTicksToWait = 100 / portTICK_PERIOD_MS;
|
||
|
|
|
||
|
|
for( ;; )
|
||
|
|
{
|
||
|
|
// Perform task functionality here.
|
||
|
|
|
||
|
|
// Set bit 0 in the event flag to note this task has reached the
|
||
|
|
// sync point. The other two tasks will set the other two bits defined
|
||
|
|
// by ALL_SYNC_BITS. All three tasks have reached the synchronisation
|
||
|
|
// point when all the ALL_SYNC_BITS are set. Wait a maximum of 100ms
|
||
|
|
// for this to happen.
|
||
|
|
uxReturn = xEventGroupSync( xEventBits, TASK_0_BIT, ALL_SYNC_BITS, xTicksToWait );
|
||
|
|
|
||
|
|
if( ( uxReturn & ALL_SYNC_BITS ) == ALL_SYNC_BITS )
|
||
|
|
{
|
||
|
|
// All three tasks reached the synchronisation point before the call
|
||
|
|
// to xEventGroupSync() timed out.
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void vTask1( void *pvParameters )
|
||
|
|
{
|
||
|
|
for( ;; )
|
||
|
|
{
|
||
|
|
// Perform task functionality here.
|
||
|
|
|
||
|
|
// Set bit 1 in the event flag to note this task has reached the
|
||
|
|
// synchronisation point. The other two tasks will set the other two
|
||
|
|
// bits defined by ALL_SYNC_BITS. All three tasks have reached the
|
||
|
|
// synchronisation point when all the ALL_SYNC_BITS are set. Wait
|
||
|
|
// indefinitely for this to happen.
|
||
|
|
xEventGroupSync( xEventBits, TASK_1_BIT, ALL_SYNC_BITS, portMAX_DELAY );
|
||
|
|
|
||
|
|
// xEventGroupSync() was called with an indefinite block time, so
|
||
|
|
// this task will only reach here if the syncrhonisation was made by all
|
||
|
|
// three tasks, so there is no need to test the return value.
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void vTask2( void *pvParameters )
|
||
|
|
{
|
||
|
|
for( ;; )
|
||
|
|
{
|
||
|
|
// Perform task functionality here.
|
||
|
|
|
||
|
|
// Set bit 2 in the event flag to note this task has reached the
|
||
|
|
// synchronisation point. The other two tasks will set the other two
|
||
|
|
// bits defined by ALL_SYNC_BITS. All three tasks have reached the
|
||
|
|
// synchronisation point when all the ALL_SYNC_BITS are set. Wait
|
||
|
|
// indefinitely for this to happen.
|
||
|
|
xEventGroupSync( xEventBits, TASK_2_BIT, ALL_SYNC_BITS, portMAX_DELAY );
|
||
|
|
|
||
|
|
// xEventGroupSync() was called with an indefinite block time, so
|
||
|
|
// this task will only reach here if the syncrhonisation was made by all
|
||
|
|
// three tasks, so there is no need to test the return value.
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
</pre>
|
||
|
|
* \defgroup xEventGroupSync xEventGroupSync
|
||
|
|
* \ingroup EventGroup
|
||
|
|
*/
|
||
|
|
EventBits_t xEventGroupSync( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet, const EventBits_t uxBitsToWaitFor, TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
|
||
|
|
|
||
|
|
|
||
|
|
/**
|
||
|
|
* event_groups.h
|
||
|
|
*<pre>
|
||
|
|
EventBits_t xEventGroupGetBits( EventGroupHandle_t xEventGroup );
|
||
|
|
</pre>
|
||
|
|
*
|
||
|
|
* Returns the current value of the bits in an event group. This function
|
||
|
|
* cannot be used from an interrupt.
|
||
|
|
*
|
||
|
|
* @param xEventGroup The event group being queried.
|
||
|
|
*
|
||
|
|
* @return The event group bits at the time xEventGroupGetBits() was called.
|
||
|
|
*
|
||
|
|
* \defgroup xEventGroupGetBits xEventGroupGetBits
|
||
|
|
* \ingroup EventGroup
|
||
|
|
*/
|
||
|
|
#define xEventGroupGetBits( xEventGroup ) xEventGroupClearBits( xEventGroup, 0 )
|
||
|
|
|
||
|
|
/**
|
||
|
|
* event_groups.h
|
||
|
|
*<pre>
|
||
|
|
EventBits_t xEventGroupGetBitsFromISR( EventGroupHandle_t xEventGroup );
|
||
|
|
</pre>
|
||
|
|
*
|
||
|
|
* A version of xEventGroupGetBits() that can be called from an ISR.
|
||
|
|
*
|
||
|
|
* @param xEventGroup The event group being queried.
|
||
|
|
*
|
||
|
|
* @return The event group bits at the time xEventGroupGetBitsFromISR() was called.
|
||
|
|
*
|
||
|
|
* \defgroup xEventGroupGetBitsFromISR xEventGroupGetBitsFromISR
|
||
|
|
* \ingroup EventGroup
|
||
|
|
*/
|
||
|
|
EventBits_t xEventGroupGetBitsFromISR( EventGroupHandle_t xEventGroup );
|
||
|
|
|
||
|
|
/**
|
||
|
|
* event_groups.h
|
||
|
|
*<pre>
|
||
|
|
void xEventGroupDelete( EventGroupHandle_t xEventGroup );
|
||
|
|
</pre>
|
||
|
|
*
|
||
|
|
* Delete an event group that was previously created by a call to
|
||
|
|
* xEventGroupCreate(). Tasks that are blocked on the event group will be
|
||
|
|
* unblocked and obtain 0 as the event group's value.
|
||
|
|
*
|
||
|
|
* @param xEventGroup The event group being deleted.
|
||
|
|
*/
|
||
|
|
void vEventGroupDelete( EventGroupHandle_t xEventGroup );
|
||
|
|
|
||
|
|
/* For internal use only. */
|
||
|
|
void vEventGroupSetBitsCallback( void *pvEventGroup, const uint32_t ulBitsToSet );
|
||
|
|
void vEventGroupClearBitsCallback( void *pvEventGroup, const uint32_t ulBitsToClear );
|
||
|
|
|
||
|
|
#if (configUSE_TRACE_FACILITY == 1)
|
||
|
|
UBaseType_t uxEventGroupGetNumber( void* xEventGroup );
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#ifdef __cplusplus
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#endif /* EVENT_GROUPS_H */
|
||
|
|
|
||
|
|
|