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762 lines
28 KiB
762 lines
28 KiB
/*
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FreeRTOS V9.0.0 - Copyright (C) 2016 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 CO_ROUTINE_H
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#define CO_ROUTINE_H
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#ifndef INC_FREERTOS_H
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#error "include FreeRTOS.h must appear in source files before include croutine.h"
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#endif
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#include "list.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Used to hide the implementation of the co-routine control block. The
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control block structure however has to be included in the header due to
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the macro implementation of the co-routine functionality. */
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typedef void * CoRoutineHandle_t;
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/* Defines the prototype to which co-routine functions must conform. */
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typedef void (*crCOROUTINE_CODE)( CoRoutineHandle_t, UBaseType_t );
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typedef struct corCoRoutineControlBlock
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{
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crCOROUTINE_CODE pxCoRoutineFunction;
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ListItem_t xGenericListItem; /*< List item used to place the CRCB in ready and blocked queues. */
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ListItem_t xEventListItem; /*< List item used to place the CRCB in event lists. */
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UBaseType_t uxPriority; /*< The priority of the co-routine in relation to other co-routines. */
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UBaseType_t uxIndex; /*< Used to distinguish between co-routines when multiple co-routines use the same co-routine function. */
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uint16_t uxState; /*< Used internally by the co-routine implementation. */
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} CRCB_t; /* Co-routine control block. Note must be identical in size down to uxPriority with TCB_t. */
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/**
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* croutine. h
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*<pre>
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BaseType_t xCoRoutineCreate(
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crCOROUTINE_CODE pxCoRoutineCode,
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UBaseType_t uxPriority,
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UBaseType_t uxIndex
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);</pre>
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*
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* Create a new co-routine and add it to the list of co-routines that are
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* ready to run.
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*
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* @param pxCoRoutineCode Pointer to the co-routine function. Co-routine
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* functions require special syntax - see the co-routine section of the WEB
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* documentation for more information.
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*
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* @param uxPriority The priority with respect to other co-routines at which
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* the co-routine will run.
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*
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* @param uxIndex Used to distinguish between different co-routines that
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* execute the same function. See the example below and the co-routine section
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* of the WEB documentation for further information.
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*
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* @return pdPASS if the co-routine was successfully created and added to a ready
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* list, otherwise an error code defined with ProjDefs.h.
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*
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* Example usage:
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<pre>
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// Co-routine to be created.
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void vFlashCoRoutine( CoRoutineHandle_t xHandle, UBaseType_t uxIndex )
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{
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// Variables in co-routines must be declared static if they must maintain value across a blocking call.
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// This may not be necessary for const variables.
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static const char cLedToFlash[ 2 ] = { 5, 6 };
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static const TickType_t uxFlashRates[ 2 ] = { 200, 400 };
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// Must start every co-routine with a call to crSTART();
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crSTART( xHandle );
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for( ;; )
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{
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// This co-routine just delays for a fixed period, then toggles
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// an LED. Two co-routines are created using this function, so
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// the uxIndex parameter is used to tell the co-routine which
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// LED to flash and how int32_t to delay. This assumes xQueue has
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// already been created.
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vParTestToggleLED( cLedToFlash[ uxIndex ] );
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crDELAY( xHandle, uxFlashRates[ uxIndex ] );
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}
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// Must end every co-routine with a call to crEND();
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crEND();
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}
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// Function that creates two co-routines.
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void vOtherFunction( void )
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{
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uint8_t ucParameterToPass;
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TaskHandle_t xHandle;
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// Create two co-routines at priority 0. The first is given index 0
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// so (from the code above) toggles LED 5 every 200 ticks. The second
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// is given index 1 so toggles LED 6 every 400 ticks.
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for( uxIndex = 0; uxIndex < 2; uxIndex++ )
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{
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xCoRoutineCreate( vFlashCoRoutine, 0, uxIndex );
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}
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}
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</pre>
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* \defgroup xCoRoutineCreate xCoRoutineCreate
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* \ingroup Tasks
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*/
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BaseType_t xCoRoutineCreate( crCOROUTINE_CODE pxCoRoutineCode, UBaseType_t uxPriority, UBaseType_t uxIndex );
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/**
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* croutine. h
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*<pre>
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void vCoRoutineSchedule( void );</pre>
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*
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* Run a co-routine.
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*
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* vCoRoutineSchedule() executes the highest priority co-routine that is able
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* to run. The co-routine will execute until it either blocks, yields or is
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* preempted by a task. Co-routines execute cooperatively so one
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* co-routine cannot be preempted by another, but can be preempted by a task.
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*
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* If an application comprises of both tasks and co-routines then
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* vCoRoutineSchedule should be called from the idle task (in an idle task
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* hook).
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*
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* Example usage:
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<pre>
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// This idle task hook will schedule a co-routine each time it is called.
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// The rest of the idle task will execute between co-routine calls.
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void vApplicationIdleHook( void )
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{
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vCoRoutineSchedule();
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}
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// Alternatively, if you do not require any other part of the idle task to
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// execute, the idle task hook can call vCoRoutineScheduler() within an
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// infinite loop.
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void vApplicationIdleHook( void )
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{
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for( ;; )
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{
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vCoRoutineSchedule();
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}
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}
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</pre>
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* \defgroup vCoRoutineSchedule vCoRoutineSchedule
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* \ingroup Tasks
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*/
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void vCoRoutineSchedule( void );
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/**
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* croutine. h
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* <pre>
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crSTART( CoRoutineHandle_t xHandle );</pre>
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*
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* This macro MUST always be called at the start of a co-routine function.
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*
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* Example usage:
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<pre>
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// Co-routine to be created.
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void vACoRoutine( CoRoutineHandle_t xHandle, UBaseType_t uxIndex )
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{
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// Variables in co-routines must be declared static if they must maintain value across a blocking call.
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static int32_t ulAVariable;
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// Must start every co-routine with a call to crSTART();
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crSTART( xHandle );
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for( ;; )
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{
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// Co-routine functionality goes here.
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}
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// Must end every co-routine with a call to crEND();
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crEND();
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}</pre>
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* \defgroup crSTART crSTART
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* \ingroup Tasks
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*/
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#define crSTART( pxCRCB ) switch( ( ( CRCB_t * )( pxCRCB ) )->uxState ) { case 0:
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/**
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* croutine. h
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* <pre>
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crEND();</pre>
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*
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* This macro MUST always be called at the end of a co-routine function.
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*
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* Example usage:
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<pre>
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// Co-routine to be created.
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void vACoRoutine( CoRoutineHandle_t xHandle, UBaseType_t uxIndex )
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{
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// Variables in co-routines must be declared static if they must maintain value across a blocking call.
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static int32_t ulAVariable;
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// Must start every co-routine with a call to crSTART();
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crSTART( xHandle );
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for( ;; )
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{
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// Co-routine functionality goes here.
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}
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// Must end every co-routine with a call to crEND();
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crEND();
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}</pre>
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* \defgroup crSTART crSTART
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* \ingroup Tasks
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*/
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#define crEND() }
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/*
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* These macros are intended for internal use by the co-routine implementation
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* only. The macros should not be used directly by application writers.
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*/
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#define crSET_STATE0( xHandle ) ( ( CRCB_t * )( xHandle ) )->uxState = (__LINE__ * 2); return; case (__LINE__ * 2):
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#define crSET_STATE1( xHandle ) ( ( CRCB_t * )( xHandle ) )->uxState = ((__LINE__ * 2)+1); return; case ((__LINE__ * 2)+1):
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/**
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* croutine. h
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*<pre>
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crDELAY( CoRoutineHandle_t xHandle, TickType_t xTicksToDelay );</pre>
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*
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* Delay a co-routine for a fixed period of time.
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*
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* crDELAY can only be called from the co-routine function itself - not
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* from within a function called by the co-routine function. This is because
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* co-routines do not maintain their own stack.
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*
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* @param xHandle The handle of the co-routine to delay. This is the xHandle
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* parameter of the co-routine function.
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*
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* @param xTickToDelay The number of ticks that the co-routine should delay
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* for. The actual amount of time this equates to is defined by
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* configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant portTICK_PERIOD_MS
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* can be used to convert ticks to milliseconds.
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*
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* Example usage:
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<pre>
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// Co-routine to be created.
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void vACoRoutine( CoRoutineHandle_t xHandle, UBaseType_t uxIndex )
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{
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// Variables in co-routines must be declared static if they must maintain value across a blocking call.
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// This may not be necessary for const variables.
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// We are to delay for 200ms.
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static const xTickType xDelayTime = 200 / portTICK_PERIOD_MS;
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// Must start every co-routine with a call to crSTART();
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crSTART( xHandle );
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for( ;; )
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{
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// Delay for 200ms.
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crDELAY( xHandle, xDelayTime );
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// Do something here.
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}
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// Must end every co-routine with a call to crEND();
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crEND();
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}</pre>
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* \defgroup crDELAY crDELAY
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* \ingroup Tasks
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*/
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#define crDELAY( xHandle, xTicksToDelay ) \
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if( ( xTicksToDelay ) > 0 ) \
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{ \
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vCoRoutineAddToDelayedList( ( xTicksToDelay ), NULL ); \
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} \
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crSET_STATE0( ( xHandle ) );
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/**
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* <pre>
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crQUEUE_SEND(
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CoRoutineHandle_t xHandle,
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QueueHandle_t pxQueue,
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void *pvItemToQueue,
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TickType_t xTicksToWait,
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BaseType_t *pxResult
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)</pre>
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*
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* The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine
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* equivalent to the xQueueSend() and xQueueReceive() functions used by tasks.
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*
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* crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas
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* xQueueSend() and xQueueReceive() can only be used from tasks.
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*
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* crQUEUE_SEND can only be called from the co-routine function itself - not
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* from within a function called by the co-routine function. This is because
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* co-routines do not maintain their own stack.
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*
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* See the co-routine section of the WEB documentation for information on
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* passing data between tasks and co-routines and between ISR's and
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* co-routines.
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*
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* @param xHandle The handle of the calling co-routine. This is the xHandle
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* parameter of the co-routine function.
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*
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* @param pxQueue The handle of the queue on which the data will be posted.
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* The handle is obtained as the return value when the queue is created using
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* the xQueueCreate() API function.
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*
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* @param pvItemToQueue A pointer to the data being posted onto the queue.
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* The number of bytes of each queued item is specified when the queue is
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* created. This number of bytes is copied from pvItemToQueue into the queue
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* itself.
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*
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* @param xTickToDelay The number of ticks that the co-routine should block
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* to wait for space to become available on the queue, should space not be
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* available immediately. The actual amount of time this equates to is defined
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* by configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant
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* portTICK_PERIOD_MS can be used to convert ticks to milliseconds (see example
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* below).
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*
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* @param pxResult The variable pointed to by pxResult will be set to pdPASS if
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* data was successfully posted onto the queue, otherwise it will be set to an
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* error defined within ProjDefs.h.
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*
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* Example usage:
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<pre>
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// Co-routine function that blocks for a fixed period then posts a number onto
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// a queue.
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static void prvCoRoutineFlashTask( CoRoutineHandle_t xHandle, UBaseType_t uxIndex )
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{
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// Variables in co-routines must be declared static if they must maintain value across a blocking call.
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static BaseType_t xNumberToPost = 0;
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static BaseType_t xResult;
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// Co-routines must begin with a call to crSTART().
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crSTART( xHandle );
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for( ;; )
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{
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// This assumes the queue has already been created.
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crQUEUE_SEND( xHandle, xCoRoutineQueue, &xNumberToPost, NO_DELAY, &xResult );
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if( xResult != pdPASS )
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{
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// The message was not posted!
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}
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// Increment the number to be posted onto the queue.
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xNumberToPost++;
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// Delay for 100 ticks.
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crDELAY( xHandle, 100 );
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}
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// Co-routines must end with a call to crEND().
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crEND();
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}</pre>
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* \defgroup crQUEUE_SEND crQUEUE_SEND
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* \ingroup Tasks
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*/
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#define crQUEUE_SEND( xHandle, pxQueue, pvItemToQueue, xTicksToWait, pxResult ) \
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{ \
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*( pxResult ) = xQueueCRSend( ( pxQueue) , ( pvItemToQueue) , ( xTicksToWait ) ); \
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if( *( pxResult ) == errQUEUE_BLOCKED ) \
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{ \
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crSET_STATE0( ( xHandle ) ); \
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*pxResult = xQueueCRSend( ( pxQueue ), ( pvItemToQueue ), 0 ); \
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} \
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if( *pxResult == errQUEUE_YIELD ) \
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{ \
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crSET_STATE1( ( xHandle ) ); \
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*pxResult = pdPASS; \
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} \
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}
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/**
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* croutine. h
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|
* <pre>
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crQUEUE_RECEIVE(
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|
CoRoutineHandle_t xHandle,
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QueueHandle_t pxQueue,
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void *pvBuffer,
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TickType_t xTicksToWait,
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BaseType_t *pxResult
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)</pre>
|
|
*
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|
* The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine
|
|
* equivalent to the xQueueSend() and xQueueReceive() functions used by tasks.
|
|
*
|
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* crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas
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* xQueueSend() and xQueueReceive() can only be used from tasks.
|
|
*
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|
* crQUEUE_RECEIVE can only be called from the co-routine function itself - not
|
|
* from within a function called by the co-routine function. This is because
|
|
* co-routines do not maintain their own stack.
|
|
*
|
|
* See the co-routine section of the WEB documentation for information on
|
|
* passing data between tasks and co-routines and between ISR's and
|
|
* co-routines.
|
|
*
|
|
* @param xHandle The handle of the calling co-routine. This is the xHandle
|
|
* parameter of the co-routine function.
|
|
*
|
|
* @param pxQueue The handle of the queue from which the data will be received.
|
|
* The handle is obtained as the return value when the queue is created using
|
|
* the xQueueCreate() API function.
|
|
*
|
|
* @param pvBuffer The buffer into which the received item is to be copied.
|
|
* The number of bytes of each queued item is specified when the queue is
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* created. This number of bytes is copied into pvBuffer.
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|
*
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|
* @param xTickToDelay The number of ticks that the co-routine should block
|
|
* to wait for data to become available from the queue, should data not be
|
|
* available immediately. The actual amount of time this equates to is defined
|
|
* by configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant
|
|
* portTICK_PERIOD_MS can be used to convert ticks to milliseconds (see the
|
|
* crQUEUE_SEND example).
|
|
*
|
|
* @param pxResult The variable pointed to by pxResult will be set to pdPASS if
|
|
* data was successfully retrieved from the queue, otherwise it will be set to
|
|
* an error code as defined within ProjDefs.h.
|
|
*
|
|
* Example usage:
|
|
<pre>
|
|
// A co-routine receives the number of an LED to flash from a queue. It
|
|
// blocks on the queue until the number is received.
|
|
static void prvCoRoutineFlashWorkTask( CoRoutineHandle_t xHandle, UBaseType_t uxIndex )
|
|
{
|
|
// Variables in co-routines must be declared static if they must maintain value across a blocking call.
|
|
static BaseType_t xResult;
|
|
static UBaseType_t uxLEDToFlash;
|
|
|
|
// All co-routines must start with a call to crSTART().
|
|
crSTART( xHandle );
|
|
|
|
for( ;; )
|
|
{
|
|
// Wait for data to become available on the queue.
|
|
crQUEUE_RECEIVE( xHandle, xCoRoutineQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
|
|
|
|
if( xResult == pdPASS )
|
|
{
|
|
// We received the LED to flash - flash it!
|
|
vParTestToggleLED( uxLEDToFlash );
|
|
}
|
|
}
|
|
|
|
crEND();
|
|
}</pre>
|
|
* \defgroup crQUEUE_RECEIVE crQUEUE_RECEIVE
|
|
* \ingroup Tasks
|
|
*/
|
|
#define crQUEUE_RECEIVE( xHandle, pxQueue, pvBuffer, xTicksToWait, pxResult ) \
|
|
{ \
|
|
*( pxResult ) = xQueueCRReceive( ( pxQueue) , ( pvBuffer ), ( xTicksToWait ) ); \
|
|
if( *( pxResult ) == errQUEUE_BLOCKED ) \
|
|
{ \
|
|
crSET_STATE0( ( xHandle ) ); \
|
|
*( pxResult ) = xQueueCRReceive( ( pxQueue) , ( pvBuffer ), 0 ); \
|
|
} \
|
|
if( *( pxResult ) == errQUEUE_YIELD ) \
|
|
{ \
|
|
crSET_STATE1( ( xHandle ) ); \
|
|
*( pxResult ) = pdPASS; \
|
|
} \
|
|
}
|
|
|
|
/**
|
|
* croutine. h
|
|
* <pre>
|
|
crQUEUE_SEND_FROM_ISR(
|
|
QueueHandle_t pxQueue,
|
|
void *pvItemToQueue,
|
|
BaseType_t xCoRoutinePreviouslyWoken
|
|
)</pre>
|
|
*
|
|
* The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the
|
|
* co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR()
|
|
* functions used by tasks.
|
|
*
|
|
* crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to
|
|
* pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and
|
|
* xQueueReceiveFromISR() can only be used to pass data between a task and and
|
|
* ISR.
|
|
*
|
|
* crQUEUE_SEND_FROM_ISR can only be called from an ISR to send data to a queue
|
|
* that is being used from within a co-routine.
|
|
*
|
|
* See the co-routine section of the WEB documentation for information on
|
|
* passing data between tasks and co-routines and between ISR's and
|
|
* co-routines.
|
|
*
|
|
* @param xQueue The handle to the queue on which the item is to be posted.
|
|
*
|
|
* @param pvItemToQueue A pointer to the item that is to be placed on the
|
|
* queue. The size of the items the queue will hold was defined when the
|
|
* queue was created, so this many bytes will be copied from pvItemToQueue
|
|
* into the queue storage area.
|
|
*
|
|
* @param xCoRoutinePreviouslyWoken This is included so an ISR can post onto
|
|
* the same queue multiple times from a single interrupt. The first call
|
|
* should always pass in pdFALSE. Subsequent calls should pass in
|
|
* the value returned from the previous call.
|
|
*
|
|
* @return pdTRUE if a co-routine was woken by posting onto the queue. This is
|
|
* used by the ISR to determine if a context switch may be required following
|
|
* the ISR.
|
|
*
|
|
* Example usage:
|
|
<pre>
|
|
// A co-routine that blocks on a queue waiting for characters to be received.
|
|
static void vReceivingCoRoutine( CoRoutineHandle_t xHandle, UBaseType_t uxIndex )
|
|
{
|
|
char cRxedChar;
|
|
BaseType_t xResult;
|
|
|
|
// All co-routines must start with a call to crSTART().
|
|
crSTART( xHandle );
|
|
|
|
for( ;; )
|
|
{
|
|
// Wait for data to become available on the queue. This assumes the
|
|
// queue xCommsRxQueue has already been created!
|
|
crQUEUE_RECEIVE( xHandle, xCommsRxQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );
|
|
|
|
// Was a character received?
|
|
if( xResult == pdPASS )
|
|
{
|
|
// Process the character here.
|
|
}
|
|
}
|
|
|
|
// All co-routines must end with a call to crEND().
|
|
crEND();
|
|
}
|
|
|
|
// An ISR that uses a queue to send characters received on a serial port to
|
|
// a co-routine.
|
|
void vUART_ISR( void )
|
|
{
|
|
char cRxedChar;
|
|
BaseType_t xCRWokenByPost = pdFALSE;
|
|
|
|
// We loop around reading characters until there are none left in the UART.
|
|
while( UART_RX_REG_NOT_EMPTY() )
|
|
{
|
|
// Obtain the character from the UART.
|
|
cRxedChar = UART_RX_REG;
|
|
|
|
// Post the character onto a queue. xCRWokenByPost will be pdFALSE
|
|
// the first time around the loop. If the post causes a co-routine
|
|
// to be woken (unblocked) then xCRWokenByPost will be set to pdTRUE.
|
|
// In this manner we can ensure that if more than one co-routine is
|
|
// blocked on the queue only one is woken by this ISR no matter how
|
|
// many characters are posted to the queue.
|
|
xCRWokenByPost = crQUEUE_SEND_FROM_ISR( xCommsRxQueue, &cRxedChar, xCRWokenByPost );
|
|
}
|
|
}</pre>
|
|
* \defgroup crQUEUE_SEND_FROM_ISR crQUEUE_SEND_FROM_ISR
|
|
* \ingroup Tasks
|
|
*/
|
|
#define crQUEUE_SEND_FROM_ISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken ) xQueueCRSendFromISR( ( pxQueue ), ( pvItemToQueue ), ( xCoRoutinePreviouslyWoken ) )
|
|
|
|
|
|
/**
|
|
* croutine. h
|
|
* <pre>
|
|
crQUEUE_SEND_FROM_ISR(
|
|
QueueHandle_t pxQueue,
|
|
void *pvBuffer,
|
|
BaseType_t * pxCoRoutineWoken
|
|
)</pre>
|
|
*
|
|
* The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the
|
|
* co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR()
|
|
* functions used by tasks.
|
|
*
|
|
* crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to
|
|
* pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and
|
|
* xQueueReceiveFromISR() can only be used to pass data between a task and and
|
|
* ISR.
|
|
*
|
|
* crQUEUE_RECEIVE_FROM_ISR can only be called from an ISR to receive data
|
|
* from a queue that is being used from within a co-routine (a co-routine
|
|
* posted to the queue).
|
|
*
|
|
* See the co-routine section of the WEB documentation for information on
|
|
* passing data between tasks and co-routines and between ISR's and
|
|
* co-routines.
|
|
*
|
|
* @param xQueue The handle to the queue on which the item is to be posted.
|
|
*
|
|
* @param pvBuffer A pointer to a buffer into which the received item will be
|
|
* placed. The size of the items the queue will hold was defined when the
|
|
* queue was created, so this many bytes will be copied from the queue into
|
|
* pvBuffer.
|
|
*
|
|
* @param pxCoRoutineWoken A co-routine may be blocked waiting for space to become
|
|
* available on the queue. If crQUEUE_RECEIVE_FROM_ISR causes such a
|
|
* co-routine to unblock *pxCoRoutineWoken will get set to pdTRUE, otherwise
|
|
* *pxCoRoutineWoken will remain unchanged.
|
|
*
|
|
* @return pdTRUE an item was successfully received from the queue, otherwise
|
|
* pdFALSE.
|
|
*
|
|
* Example usage:
|
|
<pre>
|
|
// A co-routine that posts a character to a queue then blocks for a fixed
|
|
// period. The character is incremented each time.
|
|
static void vSendingCoRoutine( CoRoutineHandle_t xHandle, UBaseType_t uxIndex )
|
|
{
|
|
// cChar holds its value while this co-routine is blocked and must therefore
|
|
// be declared static.
|
|
static char cCharToTx = 'a';
|
|
BaseType_t xResult;
|
|
|
|
// All co-routines must start with a call to crSTART().
|
|
crSTART( xHandle );
|
|
|
|
for( ;; )
|
|
{
|
|
// Send the next character to the queue.
|
|
crQUEUE_SEND( xHandle, xCoRoutineQueue, &cCharToTx, NO_DELAY, &xResult );
|
|
|
|
if( xResult == pdPASS )
|
|
{
|
|
// The character was successfully posted to the queue.
|
|
}
|
|
else
|
|
{
|
|
// Could not post the character to the queue.
|
|
}
|
|
|
|
// Enable the UART Tx interrupt to cause an interrupt in this
|
|
// hypothetical UART. The interrupt will obtain the character
|
|
// from the queue and send it.
|
|
ENABLE_RX_INTERRUPT();
|
|
|
|
// Increment to the next character then block for a fixed period.
|
|
// cCharToTx will maintain its value across the delay as it is
|
|
// declared static.
|
|
cCharToTx++;
|
|
if( cCharToTx > 'x' )
|
|
{
|
|
cCharToTx = 'a';
|
|
}
|
|
crDELAY( 100 );
|
|
}
|
|
|
|
// All co-routines must end with a call to crEND().
|
|
crEND();
|
|
}
|
|
|
|
// An ISR that uses a queue to receive characters to send on a UART.
|
|
void vUART_ISR( void )
|
|
{
|
|
char cCharToTx;
|
|
BaseType_t xCRWokenByPost = pdFALSE;
|
|
|
|
while( UART_TX_REG_EMPTY() )
|
|
{
|
|
// Are there any characters in the queue waiting to be sent?
|
|
// xCRWokenByPost will automatically be set to pdTRUE if a co-routine
|
|
// is woken by the post - ensuring that only a single co-routine is
|
|
// woken no matter how many times we go around this loop.
|
|
if( crQUEUE_RECEIVE_FROM_ISR( pxQueue, &cCharToTx, &xCRWokenByPost ) )
|
|
{
|
|
SEND_CHARACTER( cCharToTx );
|
|
}
|
|
}
|
|
}</pre>
|
|
* \defgroup crQUEUE_RECEIVE_FROM_ISR crQUEUE_RECEIVE_FROM_ISR
|
|
* \ingroup Tasks
|
|
*/
|
|
#define crQUEUE_RECEIVE_FROM_ISR( pxQueue, pvBuffer, pxCoRoutineWoken ) xQueueCRReceiveFromISR( ( pxQueue ), ( pvBuffer ), ( pxCoRoutineWoken ) )
|
|
|
|
/*
|
|
* This function is intended for internal use by the co-routine macros only.
|
|
* The macro nature of the co-routine implementation requires that the
|
|
* prototype appears here. The function should not be used by application
|
|
* writers.
|
|
*
|
|
* Removes the current co-routine from its ready list and places it in the
|
|
* appropriate delayed list.
|
|
*/
|
|
void vCoRoutineAddToDelayedList( TickType_t xTicksToDelay, List_t *pxEventList );
|
|
|
|
/*
|
|
* This function is intended for internal use by the queue implementation only.
|
|
* The function should not be used by application writers.
|
|
*
|
|
* Removes the highest priority co-routine from the event list and places it in
|
|
* the pending ready list.
|
|
*/
|
|
BaseType_t xCoRoutineRemoveFromEventList( const List_t *pxEventList );
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif /* CO_ROUTINE_H */
|
|
|