📄 queue.h
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} 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 */
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