/*
FreeRTOS.org V5.1.2 - Copyright (C) 2003-2009 Richard Barry.
This file is part of the FreeRTOS.org distribution.
FreeRTOS.org is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FreeRTOS.org is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FreeRTOS.org; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes FreeRTOS.org, without being obliged to provide
the source code for any proprietary components. See the licensing section
of http://www.FreeRTOS.org for full details of how and when the exception
can be applied.
***************************************************************************
***************************************************************************
* *
* Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
* *
* This is a concise, step by step, 'hands on' guide that describes both *
* general multitasking concepts and FreeRTOS specifics. It presents and *
* explains numerous examples that are written using the FreeRTOS API. *
* Full source code for all the examples is provided in an accompanying *
* .zip file. *
* *
***************************************************************************
***************************************************************************
Please ensure to read the configuration and relevant port sections of the
online documentation.
http://www.FreeRTOS.org - Documentation, latest information, license and
contact details.
http://www.SafeRTOS.com - A version that is certified for use in safety
critical systems.
http://www.OpenRTOS.com - Commercial support, development, porting,
licensing and training services.
*/
#ifndef INC_FREERTOS_H
#error "#include FreeRTOS.h" must appear in source files before "#include queue.h"
#endif
#ifndef QUEUE_H
#define QUEUE_H
#ifdef __cplusplus
extern "C" {
#endif
typedef void * xQueueHandle;
/* For internal use only. */
#define queueSEND_TO_BACK ( 0 )
#define queueSEND_TO_FRONT ( 1 )
/**
* queue. h
*
xQueueHandle xQueueCreate(
unsigned portBASE_TYPE uxQueueLength,
unsigned portBASE_TYPE uxItemSize
);
*
*
* Creates a new queue instance. This allocates the storage required by the
* new queue and returns a handle for the queue.
*
* @param uxQueueLength The maximum number of items that the queue can contain.
*
* @param uxItemSize The number of bytes each item in the queue will require.
* Items are queued by copy, not by reference, so this is the number of bytes
* that will be copied for each posted item. Each item on the queue must be
* the same size.
*
* @return If the queue is successfully create then a handle to the newly
* created queue is returned. If the queue cannot be created then 0 is
* returned.
*
* Example usage:
struct AMessage
{
portCHAR ucMessageID;
portCHAR ucData[ 20 ];
};
void vATask( void *pvParameters )
{
xQueueHandle xQueue1, xQueue2;
// Create a queue capable of containing 10 unsigned long values.
xQueue1 = xQueueCreate( 10, sizeof( unsigned portLONG ) );
if( xQueue1 == 0 )
{
// Queue was not created and must not be used.
}
// 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( xQueue2 == 0 )
{
// Queue was not created and must not be used.
}
// ... Rest of task code.
}
* \defgroup xQueueCreate xQueueCreate
* \ingroup QueueManagement
*/
xQueueHandle xQueueCreate( unsigned portBASE_TYPE uxQueueLength, unsigned portBASE_TYPE uxItemSize );
/**
* queue. h
*
portBASE_TYPE xQueueSendToToFront(
xQueueHandle xQueue,
const void * pvItemToQueue,
portTickType xTicksToWait
);
*
*
* This is a macro that calls xQueueGenericSend().
*
* Post an item to the front of 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.
*
* @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
*
* Example usage:
struct AMessage
{
portCHAR ucMessageID;
portCHAR ucData[ 20 ];
} xMessage;
unsigned portLONG 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 portLONG ) );
// 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( xQueueSendToFront( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != 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;
xQueueSendToFront( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 );
}
// ... Rest of task code.
}
* \defgroup xQueueSend xQueueSend
* \ingroup QueueManagement
*/
#define xQueueSendToFront( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( xQueue, pvItemToQueue, xTicksToWait, queueSEND_TO_FRONT )
/**
* queue. h
*
portBASE_TYPE xQueueSendToBack(
xQueueHandle xQueue,
const void * pvItemToQueue,
portTickType xTicksToWait
);
*
*
* This is a macro that calls xQueueGenericSend().
*
* Post an item to the back of 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.
*
* @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
*
* Example usage:
struct AMessage
{
portCHAR ucMessageID;
portCHAR ucData[ 20 ];
} xMessage;
unsigned portLONG 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 portLONG ) );
// 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( xQueueSendToBack( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != 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;
xQueueSendToBack( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 );
}
// ... Rest of task code.
}
* \defgroup xQueueSend xQueueSend
* \ingroup QueueManagement
*/
#define xQueueSendToBack( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( xQueue, pvItemToQueue, xTicksToWait, queueSEND_TO_BACK )
/**
* queue. h
*
portBASE_TYPE xQueueSend(
xQueueHandle xQueue,
const void * pvItemToQueue,
portTickType xTicksToWait
);
*
*
* This is a macro that calls xQueueGenericSend(). It is included for
* backward compatibility with versions of FreeRTOS.org that did not
* include the xQueueSendToFront() and xQueueSendToBack() macros. It is
* equivalent to xQueueSendToBack().
*
* 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.
*
* @return pdTRUE if the item was successfully posted, otherwise errQUEUE_FULL.
*
* Example usage:
struct AMessage
{
portCHAR ucMessageID;
portCHAR ucData[ 20 ];
} xMessage;
unsigned portLONG 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 portLONG ) );
// 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( xQueueSend( xQueue1, ( void * ) &ulVar, ( portTickType ) 10 ) != 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;
xQueueSend( xQueue2, ( void * ) &pxMessage, ( portTickType ) 0 );
}
// ... Rest of task code.
}
* \defgroup xQueueSend xQueueSend
* \ingroup QueueManagement
*/
#define xQueueSend( xQueue, pvItemToQueue, xTicksToWait ) xQueueGenericSend( xQueue, pvItemToQueue, xTicksToWait, queueSEND_TO_BACK )
/**
* queue. h
*
portBASE_TYPE xQueueGenericSend(
xQueueHandle xQueue,
const void * pvItemToQueue,
portTickType xTicksToWait
portBASE_TYPE xCopyPosition
);
*
*
* 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:
struct AMessage
{
portCHAR ucMessageID;
portCHAR ucData[ 20 ];
} xMessage;
unsigned portLONG 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 portLONG ) );
// 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.
}
* \defgroup xQueueSend xQueueSend
* \ingroup QueueManagement
*/
signed portBASE_TYPE xQueueGenericSend( xQueueHandle xQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition );
/**
* queue. h
*
portBASE_TYPE xQueuePeek(
xQueueHandle xQueue,
void *pvBuffer,
portTickType xTicksToWait
);
*
* 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:
struct AMessage
{
portCHAR ucMessageID;
portCHAR 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.
}
* \defgroup xQueueReceive xQueueReceive
* \ingroup QueueManagement
*/
#define xQueuePeek( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( xQueue, pvBuffer, xTicksToWait, pdTRUE )
/**
* queue. h
*
portBASE_TYPE xQueueReceive(
xQueueHandle xQueue,
void *pvBuffer,
portTickType xTicksToWait
);
*
* 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:
struct AMessage
{
portCHAR ucMessageID;
portCHAR 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.
}
* \defgroup xQueueReceive xQueueReceive
* \ingroup QueueManagement
*/
#define xQueueReceive( xQueue, pvBuffer, xTicksToWait ) xQueueGenericReceive( xQueue, pvBuffer, xTicksToWait, pdFALSE )
/**
* queue. h
*
portBASE_TYPE xQueueGenericReceive(
xQueueHandle xQueue,
void *pvBuffer,
portTickType xTicksToWait
portBASE_TYPE xJustPeek
);
*
* 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:
struct AMessage
{
portCHAR ucMessageID;
portCHAR 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.
}
* \defgroup xQueueReceive xQueueReceive
* \ingroup QueueManagement
*/
signed portBASE_TYPE xQueueGenericReceive( xQueueHandle xQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeek );
/**
* queue. h
* unsigned portBASE_TYPE uxQueueMessagesWaiting( const xQueueHandle xQueue );
*
* 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
* void vQueueDelete( xQueueHandle xQueue );
*
* 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
*
portBASE_TYPE xQueueSendToFrontFromISR(
xQueueHandle pxQueue,
const void *pvItemToQueue,
portBASE_TYPE *pxHigherPriorityTaskWoken
);
*
* 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):
void vBufferISR( void )
{
portCHAR 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 ();
}
}
*
* \defgroup xQueueSendFromISR xQueueSendFromISR
* \ingroup QueueManagement
*/
#define xQueueSendToFrontFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken, queueSEND_TO_FRONT )
/**
* queue. h
*
portBASE_TYPE xQueueSendToBackFromISR(
xQueueHandle pxQueue,
const void *pvItemToQueue,
portBASE_TYPE *pxHigherPriorityTaskWoken
);
*
* 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):
void vBufferISR( void )
{
portCHAR 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 ();
}
}
*
* \defgroup xQueueSendFromISR xQueueSendFromISR
* \ingroup QueueManagement
*/
#define xQueueSendToBackFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken, queueSEND_TO_BACK )
/**
* queue. h
*
portBASE_TYPE xQueueSendFromISR(
xQueueHandle pxQueue,
const void *pvItemToQueue,
portBASE_TYPE *pxHigherPriorityTaskWoken
);
*
* 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):
void vBufferISR( void )
{
portCHAR 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 ();
}
}
*
* \defgroup xQueueSendFromISR xQueueSendFromISR
* \ingroup QueueManagement
*/
#define xQueueSendFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( pxQueue, pvItemToQueue, pxHigherPriorityTaskWoken, queueSEND_TO_BACK )
/**
* queue. h
*
portBASE_TYPE xQueueGenericSendFromISR(
xQueueHandle pxQueue,
const void *pvItemToQueue,
portBASE_TYPE *pxHigherPriorityTaskWoken,
portBASE_TYPE xCopyPosition
);
*
* 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):
void vBufferISR( void )
{
portCHAR 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();
}
}
*
* \defgroup xQueueSendFromISR xQueueSendFromISR
* \ingroup QueueManagement
*/
signed portBASE_TYPE xQueueGenericSendFromISR( xQueueHandle pxQueue, const void * const pvItemToQueue, signed portBASE_TYPE *pxHigherPriorityTaskWoken, portBASE_TYPE xCopyPosition );
/**
* queue. h
*
portBASE_TYPE xQueueReceiveFromISR(
xQueueHandle pxQueue,
void *pvBuffer,
portBASE_TYPE *pxTaskWoken
);
*
*
* 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:
xQueueHandle xQueue;
// Function to create a queue and post some values.
void vAFunction( void *pvParameters )
{
portCHAR cValueToPost;
const portTickType xBlockTime = ( portTickType )0xff;
// Create a queue capable of containing 10 characters.
xQueue = xQueueCreate( 10, sizeof( portCHAR ) );
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;
portCHAR 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 != ( portCHAR ) pdFALSE;
{
taskYIELD ();
}
}
* \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 portCHAR *pcName );
#endif
#ifdef __cplusplus
}
#endif
#endif /* QUEUE_H */