2009-11-28 10:28:11 +01:00
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/*
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FreeRTOS V6.0.0 - Copyright (C) 2009 Real Time Engineers Ltd.
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***************************************************************************
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* *
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* If you are: *
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* *
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* + New to FreeRTOS, *
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* + Wanting to learn FreeRTOS or multitasking in general quickly *
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* + Looking for basic training, *
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* + Wanting to improve your FreeRTOS skills and productivity *
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* *
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* then take a look at the FreeRTOS eBook *
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* *
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* "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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* http://www.FreeRTOS.org/Documentation *
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* *
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* A pdf reference manual is also available. Both are usually delivered *
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* to your inbox within 20 minutes to two hours when purchased between 8am *
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* and 8pm GMT (although please allow up to 24 hours in case of *
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* exceptional circumstances). Thank you for your support! *
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* *
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***************************************************************************
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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***NOTE*** The exception to the GPL is included to allow you to distribute
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a combined work that includes FreeRTOS without being obliged to provide the
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source code for proprietary components outside of the FreeRTOS kernel.
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details. You should have received a copy of the GNU General Public
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License and the FreeRTOS license exception along with FreeRTOS; if not it
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can be viewed here: http://www.freertos.org/a00114.html and also obtained
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by writing to Richard Barry, contact details for whom are available on the
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FreeRTOS WEB site.
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1 tab == 4 spaces!
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http://www.FreeRTOS.org - Documentation, latest information, license and
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contact details.
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http://www.SafeRTOS.com - A version that is certified for use in safety
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critical systems.
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http://www.OpenRTOS.com - Commercial support, development, porting,
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licensing and training services.
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*/
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#ifndef INC_FREERTOS_H
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#error "#include FreeRTOS.h" must appear in source files before "#include queue.h"
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#endif
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2010-07-16 07:31:11 +02:00
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/**
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* @file queue.h
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* @author FreeRTOS
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* @addtogroup PIOS PIOS Core hardware abstraction layer
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* @{
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* @addtogroup FreeRTOS FreeRTOS Operating system
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* @{
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*/
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2009-11-28 10:28:11 +01:00
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#ifndef QUEUE_H
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#define QUEUE_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include "mpu_wrappers.h"
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typedef void * xQueueHandle;
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/* For internal use only. */
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#define queueSEND_TO_BACK ( 0 )
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#define queueSEND_TO_FRONT ( 1 )
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/**
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* queue. h
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* <pre>
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xQueueHandle xQueueCreate(
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unsigned portBASE_TYPE uxQueueLength,
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unsigned portBASE_TYPE uxItemSize
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);
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* </pre>
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*
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* Creates a new queue instance. This allocates the storage required by the
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* new queue and returns a handle for the queue.
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*
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* @param uxQueueLength The maximum number of items that the queue can contain.
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*
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* @param uxItemSize The number of bytes each item in the queue will require.
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* Items are queued by copy, not by reference, so this is the number of bytes
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* that will be copied for each posted item. Each item on the queue must be
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* the same size.
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*
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* @return If the queue is successfully create then a handle to the newly
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* created queue is returned. If the queue cannot be created then 0 is
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* returned.
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*
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* Example usage:
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<pre>
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struct AMessage
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{
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char ucMessageID;
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char ucData[ 20 ];
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};
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void vATask( void *pvParameters )
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{
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xQueueHandle xQueue1, xQueue2;
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// Create a queue capable of containing 10 unsigned long values.
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xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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if( xQueue1 == 0 )
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{
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// Queue was not created and must not be used.
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}
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// Create a queue capable of containing 10 pointers to AMessage structures.
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// These should be passed by pointer as they contain a lot of data.
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xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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if( xQueue2 == 0 )
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{
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// Queue was not created and must not be used.
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}
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// ... Rest of task code.
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}
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</pre>
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* \defgroup xQueueCreate xQueueCreate
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* \ingroup QueueManagement
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*/
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xQueueHandle xQueueCreate( unsigned portBASE_TYPE uxQueueLength, unsigned portBASE_TYPE uxItemSize );
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/**
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* queue. h
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* <pre>
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portBASE_TYPE xQueueSendToToFront(
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xQueueHandle xQueue,
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const void * pvItemToQueue,
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portTickType xTicksToWait
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);
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* </pre>
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*
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* This is a macro that calls xQueueGenericSend().
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*
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* Post an item to the front of a queue. The item is queued by copy, not by
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* reference. This function must not be called from an interrupt service
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* routine. See xQueueSendFromISR () for an alternative which may be used
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* in an ISR.
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*
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* @param xQueue The handle to the queue on which the item is to be posted.
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*
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* @param pvItemToQueue A pointer to the item that is to be placed on the
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* queue. The size of the items the queue will hold was defined when the
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* queue was created, so this many bytes will be copied from pvItemToQueue
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* into the queue storage area.
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*
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* @param xTicksToWait The maximum amount of time the task should block
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* waiting for space to become available on the queue, should it already
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* be full. The call will return immediately if this is set to 0 and the
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* queue is full. The time is defined in tick periods so the constant
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* portTICK_RATE_MS should be used to convert to real time if this is required.
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*
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* @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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*
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* Example usage:
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<pre>
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struct AMessage
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{
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char ucMessageID;
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char ucData[ 20 ];
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} xMessage;
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unsigned long ulVar = 10UL;
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void vATask( void *pvParameters )
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{
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xQueueHandle xQueue1, xQueue2;
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struct AMessage *pxMessage;
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// Create a queue capable of containing 10 unsigned long values.
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xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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// Create a queue capable of containing 10 pointers to AMessage structures.
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// These should be passed by pointer as they contain a lot of data.
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xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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// ...
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if( xQueue1 != 0 )
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{
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// Send an unsigned long. Wait for 10 ticks for space to become
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// available if necessary.
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if( xQueueSendToFront( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != pdPASS )
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{
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// Failed to post the message, even after 10 ticks.
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}
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}
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if( xQueue2 != 0 )
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{
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// Send a pointer to a struct AMessage object. Don't block if the
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// queue is already full.
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pxMessage = & xMessage;
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xQueueSendToFront( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 );
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}
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// ... Rest of task code.
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}
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</pre>
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* \defgroup xQueueSend xQueueSend
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* \ingroup QueueManagement
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*/
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#define xQueueSendToFront( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( xQueue, pvItemToQueue, xTicksToWait, queueSEND_TO_FRONT )
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/**
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* queue. h
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* <pre>
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portBASE_TYPE xQueueSendToBack(
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xQueueHandle xQueue,
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const void * pvItemToQueue,
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portTickType xTicksToWait
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);
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* </pre>
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*
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* This is a macro that calls xQueueGenericSend().
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*
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* Post an item to the back of a queue. The item is queued by copy, not by
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* reference. This function must not be called from an interrupt service
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|
|
* routine. See xQueueSendFromISR () for an alternative which may be used
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* in an ISR.
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*
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* @param xQueue The handle to the queue on which the item is to be posted.
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*
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* @param pvItemToQueue A pointer to the item that is to be placed on the
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* queue. The size of the items the queue will hold was defined when the
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* queue was created, so this many bytes will be copied from pvItemToQueue
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* into the queue storage area.
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*
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* @param xTicksToWait The maximum amount of time the task should block
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* waiting for space to become available on the queue, should it already
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* be full. The call will return immediately if this is set to 0 and the queue
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* is full. The time is defined in tick periods so the constant
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* portTICK_RATE_MS should be used to convert to real time if this is required.
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*
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* @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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*
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* Example usage:
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<pre>
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struct AMessage
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{
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char ucMessageID;
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char ucData[ 20 ];
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} xMessage;
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unsigned long ulVar = 10UL;
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void vATask( void *pvParameters )
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{
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xQueueHandle xQueue1, xQueue2;
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struct AMessage *pxMessage;
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// Create a queue capable of containing 10 unsigned long values.
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xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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// Create a queue capable of containing 10 pointers to AMessage structures.
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// These should be passed by pointer as they contain a lot of data.
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xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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// ...
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if( xQueue1 != 0 )
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{
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// Send an unsigned long. Wait for 10 ticks for space to become
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// available if necessary.
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if( xQueueSendToBack( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != pdPASS )
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{
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// Failed to post the message, even after 10 ticks.
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}
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}
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if( xQueue2 != 0 )
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{
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// Send a pointer to a struct AMessage object. Don't block if the
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// queue is already full.
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pxMessage = & xMessage;
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xQueueSendToBack( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 );
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}
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// ... Rest of task code.
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}
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</pre>
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* \defgroup xQueueSend xQueueSend
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* \ingroup QueueManagement
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*/
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#define xQueueSendToBack( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( xQueue, pvItemToQueue, xTicksToWait, queueSEND_TO_BACK )
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/**
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* queue. h
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* <pre>
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|
portBASE_TYPE xQueueSend(
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xQueueHandle xQueue,
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const void * pvItemToQueue,
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portTickType xTicksToWait
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);
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* </pre>
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|
*
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* This is a macro that calls xQueueGenericSend(). It is included for
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* backward compatibility with versions of FreeRTOS.org that did not
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* include the xQueueSendToFront() and xQueueSendToBack() macros. It is
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* equivalent to xQueueSendToBack().
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*
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* Post an item on a queue. The item is queued by copy, not by reference.
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|
* This function must not be called from an interrupt service routine.
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|
|
* See xQueueSendFromISR () for an alternative which may be used in an ISR.
|
|
|
|
*
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|
* @param xQueue The handle to the queue on which the item is to be posted.
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|
|
*
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|
|
|
* @param pvItemToQueue A pointer to the item that is to be placed on the
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|
|
* 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
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|
|
* into the queue storage area.
|
|
|
|
*
|
|
|
|
* @param xTicksToWait The maximum amount of time the task should block
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|
|
|
* waiting for space to become available on the queue, should it already
|
|
|
|
* be full. The call will return immediately if this is set to 0 and the
|
|
|
|
* queue is full. The time is defined in tick periods so the constant
|
|
|
|
* portTICK_RATE_MS should be used to convert to real time if this is required.
|
|
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|
*
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|
* @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
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|
*
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* Example usage:
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|
<pre>
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|
|
|
struct AMessage
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|
|
|
{
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|
char ucMessageID;
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|
char ucData[ 20 ];
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|
} xMessage;
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|
unsigned long ulVar = 10UL;
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|
void vATask( void *pvParameters )
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|
{
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|
xQueueHandle xQueue1, xQueue2;
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|
|
struct AMessage *pxMessage;
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|
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|
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// Create a queue capable of containing 10 unsigned long values.
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xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
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|
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|
// Create a queue capable of containing 10 pointers to AMessage structures.
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|
// These should be passed by pointer as they contain a lot of data.
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|
xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
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// ...
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if( xQueue1 != 0 )
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{
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|
// Send an unsigned long. Wait for 10 ticks for space to become
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|
// available if necessary.
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|
if( xQueueSend( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != pdPASS )
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|
{
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|
// Failed to post the message, even after 10 ticks.
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|
}
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|
}
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|
if( xQueue2 != 0 )
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{
|
|
|
|
// Send a pointer to a struct AMessage object. Don't block if the
|
|
|
|
// queue is already full.
|
|
|
|
pxMessage = & xMessage;
|
|
|
|
xQueueSend( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 );
|
|
|
|
}
|
|
|
|
|
|
|
|
// ... Rest of task code.
|
|
|
|
}
|
|
|
|
</pre>
|
|
|
|
* \defgroup xQueueSend xQueueSend
|
|
|
|
* \ingroup QueueManagement
|
|
|
|
*/
|
|
|
|
#define xQueueSend( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( xQueue, pvItemToQueue, xTicksToWait, queueSEND_TO_BACK )
|
|
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
* queue. h
|
|
|
|
* <pre>
|
|
|
|
portBASE_TYPE xQueueGenericSend(
|
|
|
|
xQueueHandle xQueue,
|
|
|
|
const void * pvItemToQueue,
|
|
|
|
portTickType xTicksToWait
|
|
|
|
portBASE_TYPE xCopyPosition
|
|
|
|
);
|
|
|
|
* </pre>
|
|
|
|
*
|
|
|
|
* It is preferred that the macros xQueueSend(), xQueueSendToFront() and
|
|
|
|
* xQueueSendToBack() are used in place of calling this function directly.
|
|
|
|
*
|
|
|
|
* Post an item on a queue. The item is queued by copy, not by reference.
|
|
|
|
* This function must not be called from an interrupt service routine.
|
|
|
|
* See xQueueSendFromISR () for an alternative which may be used in an ISR.
|
|
|
|
*
|
|
|
|
* @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 xTicksToWait The maximum amount of time the task should block
|
|
|
|
* waiting for space to become available on the queue, should it already
|
|
|
|
* be full. The call will return immediately if this is set to 0 and the
|
|
|
|
* queue is full. The time is defined in tick periods so the constant
|
|
|
|
* portTICK_RATE_MS should be used to convert to real time if this is required.
|
|
|
|
*
|
|
|
|
* @param xCopyPosition Can take the value queueSEND_TO_BACK to place the
|
|
|
|
* item at the back of the queue, or queueSEND_TO_FRONT to place the item
|
|
|
|
* at the front of the queue (for high priority messages).
|
|
|
|
*
|
|
|
|
* @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
|
|
|
|
*
|
|
|
|
* Example usage:
|
|
|
|
<pre>
|
|
|
|
struct AMessage
|
|
|
|
{
|
|
|
|
char ucMessageID;
|
|
|
|
char ucData[ 20 ];
|
|
|
|
} xMessage;
|
|
|
|
|
|
|
|
unsigned long ulVar = 10UL;
|
|
|
|
|
|
|
|
void vATask( void *pvParameters )
|
|
|
|
{
|
|
|
|
xQueueHandle xQueue1, xQueue2;
|
|
|
|
struct AMessage *pxMessage;
|
|
|
|
|
|
|
|
// Create a queue capable of containing 10 unsigned long values.
|
|
|
|
xQueue1 = xQueueCreate( 10, sizeof( unsigned long ) );
|
|
|
|
|
|
|
|
// Create a queue capable of containing 10 pointers to AMessage structures.
|
|
|
|
// These should be passed by pointer as they contain a lot of data.
|
|
|
|
xQueue2 = xQueueCreate( 10, sizeof( struct AMessage * ) );
|
|
|
|
|
|
|
|
// ...
|
|
|
|
|
|
|
|
if( xQueue1 != 0 )
|
|
|
|
{
|
|
|
|
// Send an unsigned long. Wait for 10 ticks for space to become
|
|
|
|
// available if necessary.
|
|
|
|
if( xQueueGenericSend( xQueue1, ( void * ) &ulVar, ( portTickType ) 10, queueSEND_TO_BACK ) != pdPASS )
|
|
|
|
{
|
|
|
|
// Failed to post the message, even after 10 ticks.
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if( xQueue2 != 0 )
|
|
|
|
{
|
|
|
|
// Send a pointer to a struct AMessage object. Don't block if the
|
|
|
|
// queue is already full.
|
|
|
|
pxMessage = & xMessage;
|
|
|
|
xQueueGenericSend( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0, queueSEND_TO_BACK );
|
|
|
|
}
|
|
|
|
|
|
|
|
// ... Rest of task code.
|
|
|
|
}
|
|
|
|
</pre>
|
|
|
|
* \defgroup xQueueSend xQueueSend
|
|
|
|
* \ingroup QueueManagement
|
|
|
|
*/
|
|
|
|
signed portBASE_TYPE xQueueGenericSend( xQueueHandle xQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition );
|
|
|
|
|
|
|
|
/**
|
|
|
|
* queue. h
|
|
|
|
* <pre>
|
|
|
|
portBASE_TYPE xQueuePeek(
|
|
|
|
xQueueHandle xQueue,
|
|
|
|
void *pvBuffer,
|
|
|
|
portTickType xTicksToWait
|
|
|
|
);</pre>
|
|
|
|
*
|
|
|
|
* This is a macro that calls the xQueueGenericReceive() function.
|
|
|
|
*
|
|
|
|
* Receive an item from a queue without removing the item from the queue.
|
|
|
|
* The item is received by copy so a buffer of adequate size must be
|
|
|
|
* provided. The number of bytes copied into the buffer was defined when
|
|
|
|
* the queue was created.
|
|
|
|
*
|
|
|
|
* Successfully received items remain on the queue so will be returned again
|
|
|
|
* by the next call, or a call to xQueueReceive().
|
|
|
|
*
|
|
|
|
* This macro must not be used in an interrupt service routine.
|
|
|
|
*
|
|
|
|
* @param pxQueue The handle to the queue from which the item is to be
|
|
|
|
* received.
|
|
|
|
*
|
|
|
|
* @param pvBuffer Pointer to the buffer into which the received item will
|
|
|
|
* be copied.
|
|
|
|
*
|
|
|
|
* @param xTicksToWait The maximum amount of time the task should block
|
|
|
|
* waiting for an item to receive should the queue be empty at the time
|
|
|
|
* of the call. The time is defined in tick periods so the constant
|
|
|
|
* portTICK_RATE_MS should be used to convert to real time if this is required.
|
|
|
|
* xQueuePeek() will return immediately if xTicksToWait is 0 and the queue
|
|
|
|
* is empty.
|
|
|
|
*
|
|
|
|
* @return pdTRUE if an item was successfully received from the queue,
|
|
|
|
* otherwise pdFALSE.
|
|
|
|
*
|
|
|
|
* Example usage:
|
|
|
|
<pre>
|
|
|
|
struct AMessage
|
|
|
|
{
|
|
|
|
char ucMessageID;
|
|
|
|
char ucData[ 20 ];
|
|
|
|
} xMessage;
|
|
|
|
|
|
|
|
xQueueHandle xQueue;
|
|
|
|
|
|
|
|
// Task to create a queue and post a value.
|
|
|
|
void vATask( void *pvParameters )
|
|
|
|
{
|
|
|
|
struct AMessage *pxMessage;
|
|
|
|
|
|
|
|
// Create a queue capable of containing 10 pointers to AMessage structures.
|
|
|
|
// These should be passed by pointer as they contain a lot of data.
|
|
|
|
xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
|
|
|
|
if( xQueue == 0 )
|
|
|
|
{
|
|
|
|
// Failed to create the queue.
|
|
|
|
}
|
|
|
|
|
|
|
|
// ...
|
|
|
|
|
|
|
|
// Send a pointer to a struct AMessage object. Don't block if the
|
|
|
|
// queue is already full.
|
|
|
|
pxMessage = & xMessage;
|
|
|
|
xQueueSend( xQueue, ( void * ) &pxMessage, ( portTickType ) 0 );
|
|
|
|
|
|
|
|
// ... Rest of task code.
|
|
|
|
}
|
|
|
|
|
|
|
|
// Task to peek the data from the queue.
|
|
|
|
void vADifferentTask( void *pvParameters )
|
|
|
|
{
|
|
|
|
struct AMessage *pxRxedMessage;
|
|
|
|
|
|
|
|
if( xQueue != 0 )
|
|
|
|
{
|
|
|
|
// Peek a message on the created queue. Block for 10 ticks if a
|
|
|
|
// message is not immediately available.
|
|
|
|
if( xQueuePeek( xQueue, &( pxRxedMessage ), ( portTickType ) 10 ) )
|
|
|
|
{
|
|
|
|
// pcRxedMessage now points to the struct AMessage variable posted
|
|
|
|
// by vATask, but the item still remains on the queue.
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// ... Rest of task code.
|
|
|
|
}
|
|
|
|
</pre>
|
|
|
|
* \defgroup xQueueReceive xQueueReceive
|
|
|
|
* \ingroup QueueManagement
|
|
|
|
*/
|
|
|
|
#define xQueuePeek( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( xQueue, pvBuffer, xTicksToWait, pdTRUE )
|
|
|
|
|
|
|
|
/**
|
|
|
|
* queue. h
|
|
|
|
* <pre>
|
|
|
|
portBASE_TYPE xQueueReceive(
|
|
|
|
xQueueHandle xQueue,
|
|
|
|
void *pvBuffer,
|
|
|
|
portTickType xTicksToWait
|
|
|
|
);</pre>
|
|
|
|
*
|
|
|
|
* This is a macro that calls the xQueueGenericReceive() function.
|
|
|
|
*
|
|
|
|
* Receive an item from a queue. The item is received by copy so a buffer of
|
|
|
|
* adequate size must be provided. The number of bytes copied into the buffer
|
|
|
|
* was defined when the queue was created.
|
|
|
|
*
|
|
|
|
* Successfully received items are removed from the queue.
|
|
|
|
*
|
|
|
|
* This function must not be used in an interrupt service routine. See
|
|
|
|
* xQueueReceiveFromISR for an alternative that can.
|
|
|
|
*
|
|
|
|
* @param pxQueue The handle to the queue from which the item is to be
|
|
|
|
* received.
|
|
|
|
*
|
|
|
|
* @param pvBuffer Pointer to the buffer into which the received item will
|
|
|
|
* be copied.
|
|
|
|
*
|
|
|
|
* @param xTicksToWait The maximum amount of time the task should block
|
|
|
|
* waiting for an item to receive should the queue be empty at the time
|
|
|
|
* of the call. xQueueReceive() will return immediately if xTicksToWait
|
|
|
|
* is zero and the queue is empty. The time is defined in tick periods so the
|
|
|
|
* constant portTICK_RATE_MS should be used to convert to real time if this is
|
|
|
|
* required.
|
|
|
|
*
|
|
|
|
* @return pdTRUE if an item was successfully received from the queue,
|
|
|
|
* otherwise pdFALSE.
|
|
|
|
*
|
|
|
|
* Example usage:
|
|
|
|
<pre>
|
|
|
|
struct AMessage
|
|
|
|
{
|
|
|
|
char ucMessageID;
|
|
|
|
char ucData[ 20 ];
|
|
|
|
} xMessage;
|
|
|
|
|
|
|
|
xQueueHandle xQueue;
|
|
|
|
|
|
|
|
// Task to create a queue and post a value.
|
|
|
|
void vATask( void *pvParameters )
|
|
|
|
{
|
|
|
|
struct AMessage *pxMessage;
|
|
|
|
|
|
|
|
// Create a queue capable of containing 10 pointers to AMessage structures.
|
|
|
|
// These should be passed by pointer as they contain a lot of data.
|
|
|
|
xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
|
|
|
|
if( xQueue == 0 )
|
|
|
|
{
|
|
|
|
// Failed to create the queue.
|
|
|
|
}
|
|
|
|
|
|
|
|
// ...
|
|
|
|
|
|
|
|
// Send a pointer to a struct AMessage object. Don't block if the
|
|
|
|
// queue is already full.
|
|
|
|
pxMessage = & xMessage;
|
|
|
|
xQueueSend( xQueue, ( void * ) &pxMessage, ( portTickType ) 0 );
|
|
|
|
|
|
|
|
// ... Rest of task code.
|
|
|
|
}
|
|
|
|
|
|
|
|
// Task to receive from the queue.
|
|
|
|
void vADifferentTask( void *pvParameters )
|
|
|
|
{
|
|
|
|
struct AMessage *pxRxedMessage;
|
|
|
|
|
|
|
|
if( xQueue != 0 )
|
|
|
|
{
|
|
|
|
// Receive a message on the created queue. Block for 10 ticks if a
|
|
|
|
// message is not immediately available.
|
|
|
|
if( xQueueReceive( xQueue, &( pxRxedMessage ), ( portTickType ) 10 ) )
|
|
|
|
{
|
|
|
|
// pcRxedMessage now points to the struct AMessage variable posted
|
|
|
|
// by vATask.
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// ... Rest of task code.
|
|
|
|
}
|
|
|
|
</pre>
|
|
|
|
* \defgroup xQueueReceive xQueueReceive
|
|
|
|
* \ingroup QueueManagement
|
|
|
|
*/
|
|
|
|
#define xQueueReceive( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( xQueue, pvBuffer, xTicksToWait, pdFALSE )
|
|
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
* queue. h
|
|
|
|
* <pre>
|
|
|
|
portBASE_TYPE xQueueGenericReceive(
|
|
|
|
xQueueHandle xQueue,
|
|
|
|
void *pvBuffer,
|
|
|
|
portTickType xTicksToWait
|
|
|
|
portBASE_TYPE xJustPeek
|
|
|
|
);</pre>
|
|
|
|
*
|
|
|
|
* It is preferred that the macro xQueueReceive() be used rather than calling
|
|
|
|
* this function directly.
|
|
|
|
*
|
|
|
|
* Receive an item from a queue. The item is received by copy so a buffer of
|
|
|
|
* adequate size must be provided. The number of bytes copied into the buffer
|
|
|
|
* was defined when the queue was created.
|
|
|
|
*
|
|
|
|
* This function must not be used in an interrupt service routine. See
|
|
|
|
* xQueueReceiveFromISR for an alternative that can.
|
|
|
|
*
|
|
|
|
* @param pxQueue The handle to the queue from which the item is to be
|
|
|
|
* received.
|
|
|
|
*
|
|
|
|
* @param pvBuffer Pointer to the buffer into which the received item will
|
|
|
|
* be copied.
|
|
|
|
*
|
|
|
|
* @param xTicksToWait The maximum amount of time the task should block
|
|
|
|
* waiting for an item to receive should the queue be empty at the time
|
|
|
|
* of the call. The time is defined in tick periods so the constant
|
|
|
|
* portTICK_RATE_MS should be used to convert to real time if this is required.
|
|
|
|
* xQueueGenericReceive() will return immediately if the queue is empty and
|
|
|
|
* xTicksToWait is 0.
|
|
|
|
*
|
|
|
|
* @param xJustPeek When set to true, the item received from the queue is not
|
|
|
|
* actually removed from the queue - meaning a subsequent call to
|
|
|
|
* xQueueReceive() will return the same item. When set to false, the item
|
|
|
|
* being received from the queue is also removed from the queue.
|
|
|
|
*
|
|
|
|
* @return pdTRUE if an item was successfully received from the queue,
|
|
|
|
* otherwise pdFALSE.
|
|
|
|
*
|
|
|
|
* Example usage:
|
|
|
|
<pre>
|
|
|
|
struct AMessage
|
|
|
|
{
|
|
|
|
char ucMessageID;
|
|
|
|
char ucData[ 20 ];
|
|
|
|
} xMessage;
|
|
|
|
|
|
|
|
xQueueHandle xQueue;
|
|
|
|
|
|
|
|
// Task to create a queue and post a value.
|
|
|
|
void vATask( void *pvParameters )
|
|
|
|
{
|
|
|
|
struct AMessage *pxMessage;
|
|
|
|
|
|
|
|
// Create a queue capable of containing 10 pointers to AMessage structures.
|
|
|
|
// These should be passed by pointer as they contain a lot of data.
|
|
|
|
xQueue = xQueueCreate( 10, sizeof( struct AMessage * ) );
|
|
|
|
if( xQueue == 0 )
|
|
|
|
{
|
|
|
|
// Failed to create the queue.
|
|
|
|
}
|
|
|
|
|
|
|
|
// ...
|
|
|
|
|
|
|
|
// Send a pointer to a struct AMessage object. Don't block if the
|
|
|
|
// queue is already full.
|
|
|
|
pxMessage = & xMessage;
|
|
|
|
xQueueSend( xQueue, ( void * ) &pxMessage, ( portTickType ) 0 );
|
|
|
|
|
|
|
|
// ... Rest of task code.
|
|
|
|
}
|
|
|
|
|
|
|
|
// Task to receive from the queue.
|
|
|
|
void vADifferentTask( void *pvParameters )
|
|
|
|
{
|
|
|
|
struct AMessage *pxRxedMessage;
|
|
|
|
|
|
|
|
if( xQueue != 0 )
|
|
|
|
{
|
|
|
|
// Receive a message on the created queue. Block for 10 ticks if a
|
|
|
|
// message is not immediately available.
|
|
|
|
if( xQueueGenericReceive( xQueue, &( pxRxedMessage ), ( portTickType ) 10 ) )
|
|
|
|
{
|
|
|
|
// pcRxedMessage now points to the struct AMessage variable posted
|
|
|
|
// by vATask.
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// ... Rest of task code.
|
|
|
|
}
|
|
|
|
</pre>
|
|
|
|
* \defgroup xQueueReceive xQueueReceive
|
|
|
|
* \ingroup QueueManagement
|
|
|
|
*/
|
|
|
|
signed portBASE_TYPE xQueueGenericReceive( xQueueHandle xQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeek );
|
|
|
|
|
|
|
|
/**
|
|
|
|
* queue. h
|
|
|
|
* <pre>unsigned portBASE_TYPE uxQueueMessagesWaiting( const xQueueHandle xQueue );</pre>
|
|
|
|
*
|
|
|
|
* Return the number of messages stored in a queue.
|
|
|
|
*
|
|
|
|
* @param xQueue A handle to the queue being queried.
|
|
|
|
*
|
|
|
|
* @return The number of messages available in the queue.
|
|
|
|
*
|
|
|
|
* \page uxQueueMessagesWaiting uxQueueMessagesWaiting
|
|
|
|
* \ingroup QueueManagement
|
|
|
|
*/
|
|
|
|
unsigned portBASE_TYPE uxQueueMessagesWaiting( const xQueueHandle xQueue );
|
|
|
|
|
|
|
|
/**
|
|
|
|
* queue. h
|
|
|
|
* <pre>void vQueueDelete( xQueueHandle xQueue );</pre>
|
|
|
|
*
|
|
|
|
* Delete a queue - freeing all the memory allocated for storing of items
|
|
|
|
* placed on the queue.
|
|
|
|
*
|
|
|
|
* @param xQueue A handle to the queue to be deleted.
|
|
|
|
*
|
|
|
|
* \page vQueueDelete vQueueDelete
|
|
|
|
* \ingroup QueueManagement
|
|
|
|
*/
|
|
|
|
void vQueueDelete( xQueueHandle xQueue );
|
|
|
|
|
|
|
|
/**
|
|
|
|
* queue. h
|
|
|
|
* <pre>
|
|
|
|
portBASE_TYPE xQueueSendToFrontFromISR(
|
|
|
|
xQueueHandle pxQueue,
|
|
|
|
const void *pvItemToQueue,
|
|
|
|
portBASE_TYPE *pxHigherPriorityTaskWoken
|
|
|
|
);
|
|
|
|
</pre>
|
|
|
|
*
|
|
|
|
* This is a macro that calls xQueueGenericSendFromISR().
|
|
|
|
*
|
|
|
|
* Post an item to the front of a queue. It is safe to use this macro from
|
|
|
|
* within an interrupt service routine.
|
|
|
|
*
|
|
|
|
* Items are queued by copy not reference so it is preferable to only
|
|
|
|
* queue small items, especially when called from an ISR. In most cases
|
|
|
|
* it would be preferable to store a pointer to the item being queued.
|
|
|
|
*
|
|
|
|
* @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 pxHigherPriorityTaskWoken xQueueSendToFrontFromISR() will set
|
|
|
|
* *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
|
|
|
|
* to unblock, and the unblocked task has a priority higher than the currently
|
|
|
|
* running task. If xQueueSendToFromFromISR() sets this value to pdTRUE then
|
|
|
|
* a context switch should be requested before the interrupt is exited.
|
|
|
|
*
|
|
|
|
* @return pdTRUE if the data was successfully sent to the queue, otherwise
|
|
|
|
* errQUEUE_FULL.
|
|
|
|
*
|
|
|
|
* Example usage for buffered IO (where the ISR can obtain more than one value
|
|
|
|
* per call):
|
|
|
|
<pre>
|
|
|
|
void vBufferISR( void )
|
|
|
|
{
|
|
|
|
char cIn;
|
|
|
|
portBASE_TYPE xHigherPrioritTaskWoken;
|
|
|
|
|
|
|
|
// We have not woken a task at the start of the ISR.
|
|
|
|
xHigherPriorityTaskWoken = pdFALSE;
|
|
|
|
|
|
|
|
// Loop until the buffer is empty.
|
|
|
|
do
|
|
|
|
{
|
|
|
|
// Obtain a byte from the buffer.
|
|
|
|
cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
|
|
|
|
|
|
|
|
// Post the byte.
|
|
|
|
xQueueSendToFrontFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
|
|
|
|
|
|
|
|
} while( portINPUT_BYTE( BUFFER_COUNT ) );
|
|
|
|
|
|
|
|
// Now the buffer is empty we can switch context if necessary.
|
|
|
|
if( xHigherPriorityTaskWoken )
|
|
|
|
{
|
|
|
|
taskYIELD ();
|
|
|
|
}
|
|
|
|
}
|
|
|
|
</pre>
|
|
|
|
*
|
|
|
|
* \defgroup xQueueSendFromISR xQueueSendFromISR
|
|
|
|
* \ingroup QueueManagement
|
|
|
|
*/
|
|
|
|
#define xQueueSendToFrontFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken, queueSEND_TO_FRONT )
|
|
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
* queue. h
|
|
|
|
* <pre>
|
|
|
|
portBASE_TYPE xQueueSendToBackFromISR(
|
|
|
|
xQueueHandle pxQueue,
|
|
|
|
const void *pvItemToQueue,
|
|
|
|
portBASE_TYPE *pxHigherPriorityTaskWoken
|
|
|
|
);
|
|
|
|
</pre>
|
|
|
|
*
|
|
|
|
* This is a macro that calls xQueueGenericSendFromISR().
|
|
|
|
*
|
|
|
|
* Post an item to the back of a queue. It is safe to use this macro from
|
|
|
|
* within an interrupt service routine.
|
|
|
|
*
|
|
|
|
* Items are queued by copy not reference so it is preferable to only
|
|
|
|
* queue small items, especially when called from an ISR. In most cases
|
|
|
|
* it would be preferable to store a pointer to the item being queued.
|
|
|
|
*
|
|
|
|
* @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 pxHigherPriorityTaskWoken xQueueSendToBackFromISR() will set
|
|
|
|
* *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
|
|
|
|
* to unblock, and the unblocked task has a priority higher than the currently
|
|
|
|
* running task. If xQueueSendToBackFromISR() sets this value to pdTRUE then
|
|
|
|
* a context switch should be requested before the interrupt is exited.
|
|
|
|
*
|
|
|
|
* @return pdTRUE if the data was successfully sent to the queue, otherwise
|
|
|
|
* errQUEUE_FULL.
|
|
|
|
*
|
|
|
|
* Example usage for buffered IO (where the ISR can obtain more than one value
|
|
|
|
* per call):
|
|
|
|
<pre>
|
|
|
|
void vBufferISR( void )
|
|
|
|
{
|
|
|
|
char cIn;
|
|
|
|
portBASE_TYPE xHigherPriorityTaskWoken;
|
|
|
|
|
|
|
|
// We have not woken a task at the start of the ISR.
|
|
|
|
xHigherPriorityTaskWoken = pdFALSE;
|
|
|
|
|
|
|
|
// Loop until the buffer is empty.
|
|
|
|
do
|
|
|
|
{
|
|
|
|
// Obtain a byte from the buffer.
|
|
|
|
cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
|
|
|
|
|
|
|
|
// Post the byte.
|
|
|
|
xQueueSendToBackFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
|
|
|
|
|
|
|
|
} while( portINPUT_BYTE( BUFFER_COUNT ) );
|
|
|
|
|
|
|
|
// Now the buffer is empty we can switch context if necessary.
|
|
|
|
if( xHigherPriorityTaskWoken )
|
|
|
|
{
|
|
|
|
taskYIELD ();
|
|
|
|
}
|
|
|
|
}
|
|
|
|
</pre>
|
|
|
|
*
|
|
|
|
* \defgroup xQueueSendFromISR xQueueSendFromISR
|
|
|
|
* \ingroup QueueManagement
|
|
|
|
*/
|
|
|
|
#define xQueueSendToBackFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken, queueSEND_TO_BACK )
|
|
|
|
|
|
|
|
/**
|
|
|
|
* queue. h
|
|
|
|
* <pre>
|
|
|
|
portBASE_TYPE xQueueSendFromISR(
|
|
|
|
xQueueHandle pxQueue,
|
|
|
|
const void *pvItemToQueue,
|
|
|
|
portBASE_TYPE *pxHigherPriorityTaskWoken
|
|
|
|
);
|
|
|
|
</pre>
|
|
|
|
*
|
|
|
|
* This is a macro that calls xQueueGenericSendFromISR(). It is included
|
|
|
|
* for backward compatibility with versions of FreeRTOS.org that did not
|
|
|
|
* include the xQueueSendToBackFromISR() and xQueueSendToFrontFromISR()
|
|
|
|
* macros.
|
|
|
|
*
|
|
|
|
* Post an item to the back of a queue. It is safe to use this function from
|
|
|
|
* within an interrupt service routine.
|
|
|
|
*
|
|
|
|
* Items are queued by copy not reference so it is preferable to only
|
|
|
|
* queue small items, especially when called from an ISR. In most cases
|
|
|
|
* it would be preferable to store a pointer to the item being queued.
|
|
|
|
*
|
|
|
|
* @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 pxHigherPriorityTaskWoken xQueueSendFromISR() will set
|
|
|
|
* *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
|
|
|
|
* to unblock, and the unblocked task has a priority higher than the currently
|
|
|
|
* running task. If xQueueSendFromISR() sets this value to pdTRUE then
|
|
|
|
* a context switch should be requested before the interrupt is exited.
|
|
|
|
*
|
|
|
|
* @return pdTRUE if the data was successfully sent to the queue, otherwise
|
|
|
|
* errQUEUE_FULL.
|
|
|
|
*
|
|
|
|
* Example usage for buffered IO (where the ISR can obtain more than one value
|
|
|
|
* per call):
|
|
|
|
<pre>
|
|
|
|
void vBufferISR( void )
|
|
|
|
{
|
|
|
|
char cIn;
|
|
|
|
portBASE_TYPE xHigherPriorityTaskWoken;
|
|
|
|
|
|
|
|
// We have not woken a task at the start of the ISR.
|
|
|
|
xHigherPriorityTaskWoken = pdFALSE;
|
|
|
|
|
|
|
|
// Loop until the buffer is empty.
|
|
|
|
do
|
|
|
|
{
|
|
|
|
// Obtain a byte from the buffer.
|
|
|
|
cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
|
|
|
|
|
|
|
|
// Post the byte.
|
|
|
|
xQueueSendFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
|
|
|
|
|
|
|
|
} while( portINPUT_BYTE( BUFFER_COUNT ) );
|
|
|
|
|
|
|
|
// Now the buffer is empty we can switch context if necessary.
|
|
|
|
if( xHigherPriorityTaskWoken )
|
|
|
|
{
|
|
|
|
// Actual macro used here is port specific.
|
|
|
|
taskYIELD_FROM_ISR ();
|
|
|
|
}
|
|
|
|
}
|
|
|
|
</pre>
|
|
|
|
*
|
|
|
|
* \defgroup xQueueSendFromISR xQueueSendFromISR
|
|
|
|
* \ingroup QueueManagement
|
|
|
|
*/
|
|
|
|
#define xQueueSendFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken, queueSEND_TO_BACK )
|
|
|
|
|
|
|
|
/**
|
|
|
|
* queue. h
|
|
|
|
* <pre>
|
|
|
|
portBASE_TYPE xQueueGenericSendFromISR(
|
|
|
|
xQueueHandle pxQueue,
|
|
|
|
const void *pvItemToQueue,
|
|
|
|
portBASE_TYPE *pxHigherPriorityTaskWoken,
|
|
|
|
portBASE_TYPE xCopyPosition
|
|
|
|
);
|
|
|
|
</pre>
|
|
|
|
*
|
|
|
|
* It is preferred that the macros xQueueSendFromISR(),
|
|
|
|
* xQueueSendToFrontFromISR() and xQueueSendToBackFromISR() be used in place
|
|
|
|
* of calling this function directly.
|
|
|
|
*
|
|
|
|
* Post an item on a queue. It is safe to use this function from within an
|
|
|
|
* interrupt service routine.
|
|
|
|
*
|
|
|
|
* Items are queued by copy not reference so it is preferable to only
|
|
|
|
* queue small items, especially when called from an ISR. In most cases
|
|
|
|
* it would be preferable to store a pointer to the item being queued.
|
|
|
|
*
|
|
|
|
* @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 pxHigherPriorityTaskWoken xQueueGenericSendFromISR() will set
|
|
|
|
* *pxHigherPriorityTaskWoken to pdTRUE if sending to the queue caused a task
|
|
|
|
* to unblock, and the unblocked task has a priority higher than the currently
|
|
|
|
* running task. If xQueueGenericSendFromISR() sets this value to pdTRUE then
|
|
|
|
* a context switch should be requested before the interrupt is exited.
|
|
|
|
*
|
|
|
|
* @param xCopyPosition Can take the value queueSEND_TO_BACK to place the
|
|
|
|
* item at the back of the queue, or queueSEND_TO_FRONT to place the item
|
|
|
|
* at the front of the queue (for high priority messages).
|
|
|
|
*
|
|
|
|
* @return pdTRUE if the data was successfully sent to the queue, otherwise
|
|
|
|
* errQUEUE_FULL.
|
|
|
|
*
|
|
|
|
* Example usage for buffered IO (where the ISR can obtain more than one value
|
|
|
|
* per call):
|
|
|
|
<pre>
|
|
|
|
void vBufferISR( void )
|
|
|
|
{
|
|
|
|
char cIn;
|
|
|
|
portBASE_TYPE xHigherPriorityTaskWokenByPost;
|
|
|
|
|
|
|
|
// We have not woken a task at the start of the ISR.
|
|
|
|
xHigherPriorityTaskWokenByPost = pdFALSE;
|
|
|
|
|
|
|
|
// Loop until the buffer is empty.
|
|
|
|
do
|
|
|
|
{
|
|
|
|
// Obtain a byte from the buffer.
|
|
|
|
cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
|
|
|
|
|
|
|
|
// Post each byte.
|
|
|
|
xQueueGenericSendFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWokenByPost, queueSEND_TO_BACK );
|
|
|
|
|
|
|
|
} while( portINPUT_BYTE( BUFFER_COUNT ) );
|
|
|
|
|
|
|
|
// Now the buffer is empty we can switch context if necessary. Note that the
|
|
|
|
// name of the yield function required is port specific.
|
|
|
|
if( xHigherPriorityTaskWokenByPost )
|
|
|
|
{
|
|
|
|
taskYIELD_YIELD_FROM_ISR();
|
|
|
|
}
|
|
|
|
}
|
|
|
|
</pre>
|
|
|
|
*
|
|
|
|
* \defgroup xQueueSendFromISR xQueueSendFromISR
|
|
|
|
* \ingroup QueueManagement
|
|
|
|
*/
|
|
|
|
signed portBASE_TYPE xQueueGenericSendFromISR( xQueueHandle pxQueue, const void * const pvItemToQueue, signed portBASE_TYPE *pxHigherPriorityTaskWoken, portBASE_TYPE xCopyPosition );
|
|
|
|
|
|
|
|
/**
|
|
|
|
* queue. h
|
|
|
|
* <pre>
|
|
|
|
portBASE_TYPE xQueueReceiveFromISR(
|
|
|
|
xQueueHandle pxQueue,
|
|
|
|
void *pvBuffer,
|
|
|
|
portBASE_TYPE *pxTaskWoken
|
|
|
|
);
|
|
|
|
* </pre>
|
|
|
|
*
|
|
|
|
* Receive an item from a queue. It is safe to use this function from within an
|
|
|
|
* interrupt service routine.
|
|
|
|
*
|
|
|
|
* @param pxQueue The handle to the queue from which the item is to be
|
|
|
|
* received.
|
|
|
|
*
|
|
|
|
* @param pvBuffer Pointer to the buffer into which the received item will
|
|
|
|
* be copied.
|
|
|
|
*
|
|
|
|
* @param pxTaskWoken A task may be blocked waiting for space to become
|
|
|
|
* available on the queue. If xQueueReceiveFromISR causes such a task to
|
|
|
|
* unblock *pxTaskWoken will get set to pdTRUE, otherwise *pxTaskWoken will
|
|
|
|
* remain unchanged.
|
|
|
|
*
|
|
|
|
* @return pdTRUE if an item was successfully received from the queue,
|
|
|
|
* otherwise pdFALSE.
|
|
|
|
*
|
|
|
|
* Example usage:
|
|
|
|
<pre>
|
|
|
|
|
|
|
|
xQueueHandle xQueue;
|
|
|
|
|
|
|
|
// Function to create a queue and post some values.
|
|
|
|
void vAFunction( void *pvParameters )
|
|
|
|
{
|
|
|
|
char cValueToPost;
|
|
|
|
const portTickType xBlockTime = ( portTickType )0xff;
|
|
|
|
|
|
|
|
// Create a queue capable of containing 10 characters.
|
|
|
|
xQueue = xQueueCreate( 10, sizeof( char ) );
|
|
|
|
if( xQueue == 0 )
|
|
|
|
{
|
|
|
|
// Failed to create the queue.
|
|
|
|
}
|
|
|
|
|
|
|
|
// ...
|
|
|
|
|
|
|
|
// Post some characters that will be used within an ISR. If the queue
|
|
|
|
// is full then this task will block for xBlockTime ticks.
|
|
|
|
cValueToPost = 'a';
|
|
|
|
xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime );
|
|
|
|
cValueToPost = 'b';
|
|
|
|
xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime );
|
|
|
|
|
|
|
|
// ... keep posting characters ... this task may block when the queue
|
|
|
|
// becomes full.
|
|
|
|
|
|
|
|
cValueToPost = 'c';
|
|
|
|
xQueueSend( xQueue, ( void * ) &cValueToPost, xBlockTime );
|
|
|
|
}
|
|
|
|
|
|
|
|
// ISR that outputs all the characters received on the queue.
|
|
|
|
void vISR_Routine( void )
|
|
|
|
{
|
|
|
|
portBASE_TYPE xTaskWokenByReceive = pdFALSE;
|
|
|
|
char cRxedChar;
|
|
|
|
|
|
|
|
while( xQueueReceiveFromISR( xQueue, ( void * ) &cRxedChar, &xTaskWokenByReceive) )
|
|
|
|
{
|
|
|
|
// A character was received. Output the character now.
|
|
|
|
vOutputCharacter( cRxedChar );
|
|
|
|
|
|
|
|
// If removing the character from the queue woke the task that was
|
|
|
|
// posting onto the queue cTaskWokenByReceive will have been set to
|
|
|
|
// pdTRUE. No matter how many times this loop iterates only one
|
|
|
|
// task will be woken.
|
|
|
|
}
|
|
|
|
|
|
|
|
if( cTaskWokenByPost != ( char ) pdFALSE;
|
|
|
|
{
|
|
|
|
taskYIELD ();
|
|
|
|
}
|
|
|
|
}
|
|
|
|
</pre>
|
|
|
|
* \defgroup xQueueReceiveFromISR xQueueReceiveFromISR
|
|
|
|
* \ingroup QueueManagement
|
|
|
|
*/
|
|
|
|
signed portBASE_TYPE xQueueReceiveFromISR( xQueueHandle pxQueue, void * const pvBuffer, signed portBASE_TYPE *pxTaskWoken );
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Utilities to query queue that are safe to use from an ISR. These utilities
|
|
|
|
* should be used only from witin an ISR, or within a critical section.
|
|
|
|
*/
|
|
|
|
signed portBASE_TYPE xQueueIsQueueEmptyFromISR( const xQueueHandle pxQueue );
|
|
|
|
signed portBASE_TYPE xQueueIsQueueFullFromISR( const xQueueHandle pxQueue );
|
|
|
|
unsigned portBASE_TYPE uxQueueMessagesWaitingFromISR( const xQueueHandle pxQueue );
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
* xQueueAltGenericSend() is an alternative version of xQueueGenericSend().
|
|
|
|
* Likewise xQueueAltGenericReceive() is an alternative version of
|
|
|
|
* xQueueGenericReceive().
|
|
|
|
*
|
|
|
|
* The source code that implements the alternative (Alt) API is much
|
|
|
|
* simpler because it executes everything from within a critical section.
|
|
|
|
* This is the approach taken by many other RTOSes, but FreeRTOS.org has the
|
|
|
|
* preferred fully featured API too. The fully featured API has more
|
|
|
|
* complex code that takes longer to execute, but makes much less use of
|
|
|
|
* critical sections. Therefore the alternative API sacrifices interrupt
|
|
|
|
* responsiveness to gain execution speed, whereas the fully featured API
|
|
|
|
* sacrifices execution speed to ensure better interrupt responsiveness.
|
|
|
|
*/
|
|
|
|
signed portBASE_TYPE xQueueAltGenericSend( xQueueHandle pxQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition );
|
|
|
|
signed portBASE_TYPE xQueueAltGenericReceive( xQueueHandle pxQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeeking );
|
|
|
|
#define xQueueAltSendToFront( xQueue, pvItemToQueue, xTicksToWait ) xQueueAltGenericSend( xQueue, pvItemToQueue, xTicksToWait, queueSEND_TO_FRONT )
|
|
|
|
#define xQueueAltSendToBack( xQueue, pvItemToQueue, xTicksToWait ) xQueueAltGenericSend( xQueue, pvItemToQueue, xTicksToWait, queueSEND_TO_BACK )
|
|
|
|
#define xQueueAltReceive( xQueue, pvBuffer, xTicksToWait ) xQueueAltGenericReceive( xQueue, pvBuffer, xTicksToWait, pdFALSE )
|
|
|
|
#define xQueueAltPeek( xQueue, pvBuffer, xTicksToWait ) xQueueAltGenericReceive( xQueue, pvBuffer, xTicksToWait, pdTRUE )
|
|
|
|
|
|
|
|
/*
|
|
|
|
* The functions defined above are for passing data to and from tasks. The
|
|
|
|
* functions below are the equivalents for passing data to and from
|
|
|
|
* co-routines.
|
|
|
|
*
|
|
|
|
* These functions are called from the co-routine macro implementation and
|
|
|
|
* should not be called directly from application code. Instead use the macro
|
|
|
|
* wrappers defined within croutine.h.
|
|
|
|
*/
|
|
|
|
signed portBASE_TYPE xQueueCRSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xCoRoutinePreviouslyWoken );
|
|
|
|
signed portBASE_TYPE xQueueCRReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxTaskWoken );
|
|
|
|
signed portBASE_TYPE xQueueCRSend( xQueueHandle pxQueue, const void *pvItemToQueue, portTickType xTicksToWait );
|
|
|
|
signed portBASE_TYPE xQueueCRReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait );
|
|
|
|
|
|
|
|
/*
|
|
|
|
* For internal use only. Use xSemaphoreCreateMutex() or
|
|
|
|
* xSemaphoreCreateCounting() instead of calling these functions directly.
|
|
|
|
*/
|
|
|
|
xQueueHandle xQueueCreateMutex( void );
|
|
|
|
xQueueHandle xQueueCreateCountingSemaphore( unsigned portBASE_TYPE uxCountValue, unsigned portBASE_TYPE uxInitialCount );
|
|
|
|
|
|
|
|
/*
|
|
|
|
* For internal use only. Use xSemaphoreTakeMutexRecursive() or
|
|
|
|
* xSemaphoreGiveMutexRecursive() instead of calling these functions directly.
|
|
|
|
*/
|
|
|
|
portBASE_TYPE xQueueTakeMutexRecursive( xQueueHandle xMutex, portTickType xBlockTime );
|
|
|
|
portBASE_TYPE xQueueGiveMutexRecursive( xQueueHandle xMutex );
|
|
|
|
|
|
|
|
/*
|
|
|
|
* The registry is provided as a means for kernel aware debuggers to
|
|
|
|
* locate queues, semaphores and mutexes. Call vQueueAddToRegistry() add
|
|
|
|
* a queue, semaphore or mutex handle to the registry if you want the handle
|
|
|
|
* to be available to a kernel aware debugger. If you are not using a kernel
|
|
|
|
* aware debugger then this function can be ignored.
|
|
|
|
*
|
|
|
|
* configQUEUE_REGISTRY_SIZE defines the maximum number of handles the
|
|
|
|
* registry can hold. configQUEUE_REGISTRY_SIZE must be greater than 0
|
|
|
|
* within FreeRTOSConfig.h for the registry to be available. Its value
|
|
|
|
* does not effect the number of queues, semaphores and mutexes that can be
|
|
|
|
* created - just the number that the registry can hold.
|
|
|
|
*
|
|
|
|
* @param xQueue The handle of the queue being added to the registry. This
|
|
|
|
* is the handle returned by a call to xQueueCreate(). Semaphore and mutex
|
|
|
|
* handles can also be passed in here.
|
|
|
|
*
|
|
|
|
* @param pcName The name to be associated with the handle. This is the
|
|
|
|
* name that the kernel aware debugger will display.
|
|
|
|
*/
|
|
|
|
#if configQUEUE_REGISTRY_SIZE > 0
|
|
|
|
void vQueueAddToRegistry( xQueueHandle xQueue, signed char *pcName );
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
#ifdef __cplusplus
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
|
|
#endif /* QUEUE_H */
|
|
|
|
|