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***************************************************************************
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***************************************************************************
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***************************************************************************
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*/
#ifndef EVENT_GROUPS_H
#define EVENT_GROUPS_H
#ifndef INC_FREERTOS_H
#error "include FreeRTOS.h" must appear in source files before "include event_groups.h"
#endif
/* FreeRTOS includes. */
#include "timers.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* An event group is a collection of bits to which an application can assign a
* meaning. For example, an application may create an event group to convey
* the status of various CAN bus related events in which bit 0 might mean "A CAN
* message has been received and is ready for processing", bit 1 might mean "The
* application has queued a message that is ready for sending onto the CAN
* network", and bit 2 might mean "It is time to send a SYNC message onto the
* CAN network" etc. A task can then test the bit values to see which events
* are active, and optionally enter the Blocked state to wait for a specified
* bit or a group of specified bits to be active. To continue the CAN bus
* example, a CAN controlling task can enter the Blocked state (and therefore
* not consume any processing time) until either bit 0, bit 1 or bit 2 are
* active, at which time the bit that was actually active would inform the task
* which action it had to take (process a received message, send a message, or
* send a SYNC).
*
* The event groups implementation contains intelligence to avoid race
* conditions that would otherwise occur were an application to use a simple
* variable for the same purpose. This is particularly important with respect
* to when a bit within an event group is to be cleared, and when bits have to
* be set and then tested atomically - as is the case where event groups are
* used to create a synchronisation point between multiple tasks (a
* 'rendezvous').
*
* \defgroup EventGroup
*/
/**
* event_groups.h
*
* Type by which event groups are referenced. For example, a call to
* xEventGroupCreate() returns an EventGroupHandle_t variable that can then
* be used as a parameter to other event group functions.
*
* \defgroup EventGroupHandle_t EventGroupHandle_t
* \ingroup EventGroup
*/
typedef void * EventGroupHandle_t;
/*
* The type that holds event bits always matches TickType_t - therefore the
* number of bits it holds is set by configUSE_16_BIT_TICKS (16 bits if set to 1,
* 32 bits if set to 0.
*
* \defgroup EventBits_t EventBits_t
* \ingroup EventGroup
*/
typedef TickType_t EventBits_t;
/**
* event_groups.h
*
EventGroupHandle_t xEventGroupCreate( void );
*
* Create a new event group.
*
* Internally, within the FreeRTOS implementation, event groups use a [small]
* block of memory, in which the event group's structure is stored. If an event
* groups is created using xEventGropuCreate() then the required memory is
* automatically dynamically allocated inside the xEventGroupCreate() function.
* (see http://www.freertos.org/a00111.html). If an event group is created
* using xEventGropuCreateStatic() then the application writer must instead
* provide the memory that will get used by the event group.
* xEventGroupCreateStatic() therefore allows an event group to be created
* without using any dynamic memory allocation.
*
* Although event groups are not related to ticks, for internal implementation
* reasons the number of bits available for use in an event group is dependent
* on the configUSE_16_BIT_TICKS setting in FreeRTOSConfig.h. If
* configUSE_16_BIT_TICKS is 1 then each event group contains 8 usable bits (bit
* 0 to bit 7). If configUSE_16_BIT_TICKS is set to 0 then each event group has
* 24 usable bits (bit 0 to bit 23). The EventBits_t type is used to store
* event bits within an event group.
*
* @return If the event group was created then a handle to the event group is
* returned. If there was insufficient FreeRTOS heap available to create the
* event group then NULL is returned. See http://www.freertos.org/a00111.html
*
* Example usage:
// Declare a variable to hold the created event group.
EventGroupHandle_t xCreatedEventGroup;
// Attempt to create the event group.
xCreatedEventGroup = xEventGroupCreate();
// Was the event group created successfully?
if( xCreatedEventGroup == NULL )
{
// The event group was not created because there was insufficient
// FreeRTOS heap available.
}
else
{
// The event group was created.
}
* \defgroup xEventGroupCreate xEventGroupCreate
* \ingroup EventGroup
*/
#if( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
EventGroupHandle_t xEventGroupCreate( void ) PRIVILEGED_FUNCTION;
#endif
/**
* event_groups.h
*
EventGroupHandle_t xEventGroupCreateStatic( EventGroupHandle_t * pxEventGroupBuffer );
*
* Create a new event group.
*
* Internally, within the FreeRTOS implementation, event groups use a [small]
* block of memory, in which the event group's structure is stored. If an event
* groups is created using xEventGropuCreate() then the required memory is
* automatically dynamically allocated inside the xEventGroupCreate() function.
* (see http://www.freertos.org/a00111.html). If an event group is created
* using xEventGropuCreateStatic() then the application writer must instead
* provide the memory that will get used by the event group.
* xEventGroupCreateStatic() therefore allows an event group to be created
* without using any dynamic memory allocation.
*
* Although event groups are not related to ticks, for internal implementation
* reasons the number of bits available for use in an event group is dependent
* on the configUSE_16_BIT_TICKS setting in FreeRTOSConfig.h. If
* configUSE_16_BIT_TICKS is 1 then each event group contains 8 usable bits (bit
* 0 to bit 7). If configUSE_16_BIT_TICKS is set to 0 then each event group has
* 24 usable bits (bit 0 to bit 23). The EventBits_t type is used to store
* event bits within an event group.
*
* @param pxEventGroupBuffer pxEventGroupBuffer must point to a variable of type
* StaticEventGroup_t, which will be then be used to hold the event group's data
* structures, removing the need for the memory to be allocated dynamically.
*
* @return If the event group was created then a handle to the event group is
* returned. If pxEventGroupBuffer was NULL then NULL is returned.
*
* Example usage:
// StaticEventGroup_t is a publicly accessible structure that has the same
// size and alignment requirements as the real event group structure. It is
// provided as a mechanism for applications to know the size of the event
// group (which is dependent on the architecture and configuration file
// settings) without breaking the strict data hiding policy by exposing the
// real event group internals. This StaticEventGroup_t variable is passed
// into the xSemaphoreCreateEventGroupStatic() function and is used to store
// the event group's data structures
StaticEventGroup_t xEventGroupBuffer;
// Create the event group without dynamically allocating any memory.
xEventGroup = xEventGroupCreateStatic( &xEventGroupBuffer );
*/
#if( configSUPPORT_STATIC_ALLOCATION == 1 )
EventGroupHandle_t xEventGroupCreateStatic( StaticEventGroup_t *pxEventGroupBuffer ) PRIVILEGED_FUNCTION;
#endif
/**
* event_groups.h
*
EventBits_t xEventGroupWaitBits( EventGroupHandle_t xEventGroup,
const EventBits_t uxBitsToWaitFor,
const BaseType_t xClearOnExit,
const BaseType_t xWaitForAllBits,
const TickType_t xTicksToWait );
*
* [Potentially] block to wait for one or more bits to be set within a
* previously created event group.
*
* This function cannot be called from an interrupt.
*
* @param xEventGroup The event group in which the bits are being tested. The
* event group must have previously been created using a call to
* xEventGroupCreate().
*
* @param uxBitsToWaitFor A bitwise value that indicates the bit or bits to test
* inside the event group. For example, to wait for bit 0 and/or bit 2 set
* uxBitsToWaitFor to 0x05. To wait for bits 0 and/or bit 1 and/or bit 2 set
* uxBitsToWaitFor to 0x07. Etc.
*
* @param xClearOnExit If xClearOnExit is set to pdTRUE then any bits within
* uxBitsToWaitFor that are set within the event group will be cleared before
* xEventGroupWaitBits() returns if the wait condition was met (if the function
* returns for a reason other than a timeout). If xClearOnExit is set to
* pdFALSE then the bits set in the event group are not altered when the call to
* xEventGroupWaitBits() returns.
*
* @param xWaitForAllBits If xWaitForAllBits is set to pdTRUE then
* xEventGroupWaitBits() will return when either all the bits in uxBitsToWaitFor
* are set or the specified block time expires. If xWaitForAllBits is set to
* pdFALSE then xEventGroupWaitBits() will return when any one of the bits set
* in uxBitsToWaitFor is set or the specified block time expires. The block
* time is specified by the xTicksToWait parameter.
*
* @param xTicksToWait The maximum amount of time (specified in 'ticks') to wait
* for one/all (depending on the xWaitForAllBits value) of the bits specified by
* uxBitsToWaitFor to become set.
*
* @return The value of the event group at the time either the bits being waited
* for became set, or the block time expired. Test the return value to know
* which bits were set. If xEventGroupWaitBits() returned because its timeout
* expired then not all the bits being waited for will be set. If
* xEventGroupWaitBits() returned because the bits it was waiting for were set
* then the returned value is the event group value before any bits were
* automatically cleared in the case that xClearOnExit parameter was set to
* pdTRUE.
*
* Example usage:
#define BIT_0 ( 1 << 0 )
#define BIT_4 ( 1 << 4 )
void aFunction( EventGroupHandle_t xEventGroup )
{
EventBits_t uxBits;
const TickType_t xTicksToWait = 100 / portTICK_PERIOD_MS;
// Wait a maximum of 100ms for either bit 0 or bit 4 to be set within
// the event group. Clear the bits before exiting.
uxBits = xEventGroupWaitBits(
xEventGroup, // The event group being tested.
BIT_0 | BIT_4, // The bits within the event group to wait for.
pdTRUE, // BIT_0 and BIT_4 should be cleared before returning.
pdFALSE, // Don't wait for both bits, either bit will do.
xTicksToWait ); // Wait a maximum of 100ms for either bit to be set.
if( ( uxBits & ( BIT_0 | BIT_4 ) ) == ( BIT_0 | BIT_4 ) )
{
// xEventGroupWaitBits() returned because both bits were set.
}
else if( ( uxBits & BIT_0 ) != 0 )
{
// xEventGroupWaitBits() returned because just BIT_0 was set.
}
else if( ( uxBits & BIT_4 ) != 0 )
{
// xEventGroupWaitBits() returned because just BIT_4 was set.
}
else
{
// xEventGroupWaitBits() returned because xTicksToWait ticks passed
// without either BIT_0 or BIT_4 becoming set.
}
}
* \defgroup xEventGroupWaitBits xEventGroupWaitBits
* \ingroup EventGroup
*/
EventBits_t xEventGroupWaitBits( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToWaitFor, const BaseType_t xClearOnExit, const BaseType_t xWaitForAllBits, TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
/**
* event_groups.h
*
EventBits_t xEventGroupClearBits( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToClear );
*
* Clear bits within an event group. This function cannot be called from an
* interrupt.
*
* @param xEventGroup The event group in which the bits are to be cleared.
*
* @param uxBitsToClear A bitwise value that indicates the bit or bits to clear
* in the event group. For example, to clear bit 3 only, set uxBitsToClear to
* 0x08. To clear bit 3 and bit 0 set uxBitsToClear to 0x09.
*
* @return The value of the event group before the specified bits were cleared.
*
* Example usage:
#define BIT_0 ( 1 << 0 )
#define BIT_4 ( 1 << 4 )
void aFunction( EventGroupHandle_t xEventGroup )
{
EventBits_t uxBits;
// Clear bit 0 and bit 4 in xEventGroup.
uxBits = xEventGroupClearBits(
xEventGroup, // The event group being updated.
BIT_0 | BIT_4 );// The bits being cleared.
if( ( uxBits & ( BIT_0 | BIT_4 ) ) == ( BIT_0 | BIT_4 ) )
{
// Both bit 0 and bit 4 were set before xEventGroupClearBits() was
// called. Both will now be clear (not set).
}
else if( ( uxBits & BIT_0 ) != 0 )
{
// Bit 0 was set before xEventGroupClearBits() was called. It will
// now be clear.
}
else if( ( uxBits & BIT_4 ) != 0 )
{
// Bit 4 was set before xEventGroupClearBits() was called. It will
// now be clear.
}
else
{
// Neither bit 0 nor bit 4 were set in the first place.
}
}
* \defgroup xEventGroupClearBits xEventGroupClearBits
* \ingroup EventGroup
*/
EventBits_t xEventGroupClearBits( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToClear ) PRIVILEGED_FUNCTION;
/**
* event_groups.h
*
BaseType_t xEventGroupClearBitsFromISR( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet );
*
* A version of xEventGroupClearBits() that can be called from an interrupt.
*
* Setting bits in an event group is not a deterministic operation because there
* are an unknown number of tasks that may be waiting for the bit or bits being
* set. FreeRTOS does not allow nondeterministic operations to be performed
* while interrupts are disabled, so protects event groups that are accessed
* from tasks by suspending the scheduler rather than disabling interrupts. As
* a result event groups cannot be accessed directly from an interrupt service
* routine. Therefore xEventGroupClearBitsFromISR() sends a message to the
* timer task to have the clear operation performed in the context of the timer
* task.
*
* @param xEventGroup The event group in which the bits are to be cleared.
*
* @param uxBitsToClear A bitwise value that indicates the bit or bits to clear.
* For example, to clear bit 3 only, set uxBitsToClear to 0x08. To clear bit 3
* and bit 0 set uxBitsToClear to 0x09.
*
* @return If the request to execute the function was posted successfully then
* pdPASS is returned, otherwise pdFALSE is returned. pdFALSE will be returned
* if the timer service queue was full.
*
* Example usage:
#define BIT_0 ( 1 << 0 )
#define BIT_4 ( 1 << 4 )
// An event group which it is assumed has already been created by a call to
// xEventGroupCreate().
EventGroupHandle_t xEventGroup;
void anInterruptHandler( void )
{
// Clear bit 0 and bit 4 in xEventGroup.
xResult = xEventGroupClearBitsFromISR(
xEventGroup, // The event group being updated.
BIT_0 | BIT_4 ); // The bits being set.
if( xResult == pdPASS )
{
// The message was posted successfully.
}
}
* \defgroup xEventGroupClearBitsFromISR xEventGroupClearBitsFromISR
* \ingroup EventGroup
*/
#if( configUSE_TRACE_FACILITY == 1 )
BaseType_t xEventGroupClearBitsFromISR( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet ) PRIVILEGED_FUNCTION;
#else
#define xEventGroupClearBitsFromISR( xEventGroup, uxBitsToClear ) xTimerPendFunctionCallFromISR( vEventGroupClearBitsCallback, ( void * ) xEventGroup, ( uint32_t ) uxBitsToClear, NULL )
#endif
/**
* event_groups.h
*
EventBits_t xEventGroupSetBits( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet );
*
* Set bits within an event group.
* This function cannot be called from an interrupt. xEventGroupSetBitsFromISR()
* is a version that can be called from an interrupt.
*
* Setting bits in an event group will automatically unblock tasks that are
* blocked waiting for the bits.
*
* @param xEventGroup The event group in which the bits are to be set.
*
* @param uxBitsToSet A bitwise value that indicates the bit or bits to set.
* For example, to set bit 3 only, set uxBitsToSet to 0x08. To set bit 3
* and bit 0 set uxBitsToSet to 0x09.
*
* @return The value of the event group at the time the call to
* xEventGroupSetBits() returns. There are two reasons why the returned value
* might have the bits specified by the uxBitsToSet parameter cleared. First,
* if setting a bit results in a task that was waiting for the bit leaving the
* blocked state then it is possible the bit will be cleared automatically
* (see the xClearBitOnExit parameter of xEventGroupWaitBits()). Second, any
* unblocked (or otherwise Ready state) task that has a priority above that of
* the task that called xEventGroupSetBits() will execute and may change the
* event group value before the call to xEventGroupSetBits() returns.
*
* Example usage:
#define BIT_0 ( 1 << 0 )
#define BIT_4 ( 1 << 4 )
void aFunction( EventGroupHandle_t xEventGroup )
{
EventBits_t uxBits;
// Set bit 0 and bit 4 in xEventGroup.
uxBits = xEventGroupSetBits(
xEventGroup, // The event group being updated.
BIT_0 | BIT_4 );// The bits being set.
if( ( uxBits & ( BIT_0 | BIT_4 ) ) == ( BIT_0 | BIT_4 ) )
{
// Both bit 0 and bit 4 remained set when the function returned.
}
else if( ( uxBits & BIT_0 ) != 0 )
{
// Bit 0 remained set when the function returned, but bit 4 was
// cleared. It might be that bit 4 was cleared automatically as a
// task that was waiting for bit 4 was removed from the Blocked
// state.
}
else if( ( uxBits & BIT_4 ) != 0 )
{
// Bit 4 remained set when the function returned, but bit 0 was
// cleared. It might be that bit 0 was cleared automatically as a
// task that was waiting for bit 0 was removed from the Blocked
// state.
}
else
{
// Neither bit 0 nor bit 4 remained set. It might be that a task
// was waiting for both of the bits to be set, and the bits were
// cleared as the task left the Blocked state.
}
}
* \defgroup xEventGroupSetBits xEventGroupSetBits
* \ingroup EventGroup
*/
EventBits_t xEventGroupSetBits( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet ) PRIVILEGED_FUNCTION;
/**
* event_groups.h
*
BaseType_t xEventGroupSetBitsFromISR( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet, BaseType_t *pxHigherPriorityTaskWoken );
*
* A version of xEventGroupSetBits() that can be called from an interrupt.
*
* Setting bits in an event group is not a deterministic operation because there
* are an unknown number of tasks that may be waiting for the bit or bits being
* set. FreeRTOS does not allow nondeterministic operations to be performed in
* interrupts or from critical sections. Therefore xEventGroupSetBitsFromISR()
* sends a message to the timer task to have the set operation performed in the
* context of the timer task - where a scheduler lock is used in place of a
* critical section.
*
* @param xEventGroup The event group in which the bits are to be set.
*
* @param uxBitsToSet A bitwise value that indicates the bit or bits to set.
* For example, to set bit 3 only, set uxBitsToSet to 0x08. To set bit 3
* and bit 0 set uxBitsToSet to 0x09.
*
* @param pxHigherPriorityTaskWoken As mentioned above, calling this function
* will result in a message being sent to the timer daemon task. If the
* priority of the timer daemon task is higher than the priority of the
* currently running task (the task the interrupt interrupted) then
* *pxHigherPriorityTaskWoken will be set to pdTRUE by
* xEventGroupSetBitsFromISR(), indicating that a context switch should be
* requested before the interrupt exits. For that reason
* *pxHigherPriorityTaskWoken must be initialised to pdFALSE. See the
* example code below.
*
* @return If the request to execute the function was posted successfully then
* pdPASS is returned, otherwise pdFALSE is returned. pdFALSE will be returned
* if the timer service queue was full.
*
* Example usage:
#define BIT_0 ( 1 << 0 )
#define BIT_4 ( 1 << 4 )
// An event group which it is assumed has already been created by a call to
// xEventGroupCreate().
EventGroupHandle_t xEventGroup;
void anInterruptHandler( void )
{
BaseType_t xHigherPriorityTaskWoken, xResult;
// xHigherPriorityTaskWoken must be initialised to pdFALSE.
xHigherPriorityTaskWoken = pdFALSE;
// Set bit 0 and bit 4 in xEventGroup.
xResult = xEventGroupSetBitsFromISR(
xEventGroup, // The event group being updated.
BIT_0 | BIT_4 // The bits being set.
&xHigherPriorityTaskWoken );
// Was the message posted successfully?
if( xResult == pdPASS )
{
// If xHigherPriorityTaskWoken is now set to pdTRUE then a context
// switch should be requested. The macro used is port specific and
// will be either portYIELD_FROM_ISR() or portEND_SWITCHING_ISR() -
// refer to the documentation page for the port being used.
portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
}
}
* \defgroup xEventGroupSetBitsFromISR xEventGroupSetBitsFromISR
* \ingroup EventGroup
*/
#if( configUSE_TRACE_FACILITY == 1 )
BaseType_t xEventGroupSetBitsFromISR( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet, BaseType_t *pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION;
#else
#define xEventGroupSetBitsFromISR( xEventGroup, uxBitsToSet, pxHigherPriorityTaskWoken ) xTimerPendFunctionCallFromISR( vEventGroupSetBitsCallback, ( void * ) xEventGroup, ( uint32_t ) uxBitsToSet, pxHigherPriorityTaskWoken )
#endif
/**
* event_groups.h
*
EventBits_t xEventGroupSync( EventGroupHandle_t xEventGroup,
const EventBits_t uxBitsToSet,
const EventBits_t uxBitsToWaitFor,
TickType_t xTicksToWait );
*
* Atomically set bits within an event group, then wait for a combination of
* bits to be set within the same event group. This functionality is typically
* used to synchronise multiple tasks, where each task has to wait for the other
* tasks to reach a synchronisation point before proceeding.
*
* This function cannot be used from an interrupt.
*
* The function will return before its block time expires if the bits specified
* by the uxBitsToWait parameter are set, or become set within that time. In
* this case all the bits specified by uxBitsToWait will be automatically
* cleared before the function returns.
*
* @param xEventGroup The event group in which the bits are being tested. The
* event group must have previously been created using a call to
* xEventGroupCreate().
*
* @param uxBitsToSet The bits to set in the event group before determining
* if, and possibly waiting for, all the bits specified by the uxBitsToWait
* parameter are set.
*
* @param uxBitsToWaitFor A bitwise value that indicates the bit or bits to test
* inside the event group. For example, to wait for bit 0 and bit 2 set
* uxBitsToWaitFor to 0x05. To wait for bits 0 and bit 1 and bit 2 set
* uxBitsToWaitFor to 0x07. Etc.
*
* @param xTicksToWait The maximum amount of time (specified in 'ticks') to wait
* for all of the bits specified by uxBitsToWaitFor to become set.
*
* @return The value of the event group at the time either the bits being waited
* for became set, or the block time expired. Test the return value to know
* which bits were set. If xEventGroupSync() returned because its timeout
* expired then not all the bits being waited for will be set. If
* xEventGroupSync() returned because all the bits it was waiting for were
* set then the returned value is the event group value before any bits were
* automatically cleared.
*
* Example usage:
// Bits used by the three tasks.
#define TASK_0_BIT ( 1 << 0 )
#define TASK_1_BIT ( 1 << 1 )
#define TASK_2_BIT ( 1 << 2 )
#define ALL_SYNC_BITS ( TASK_0_BIT | TASK_1_BIT | TASK_2_BIT )
// Use an event group to synchronise three tasks. It is assumed this event
// group has already been created elsewhere.
EventGroupHandle_t xEventBits;
void vTask0( void *pvParameters )
{
EventBits_t uxReturn;
TickType_t xTicksToWait = 100 / portTICK_PERIOD_MS;
for( ;; )
{
// Perform task functionality here.
// Set bit 0 in the event flag to note this task has reached the
// sync point. The other two tasks will set the other two bits defined
// by ALL_SYNC_BITS. All three tasks have reached the synchronisation
// point when all the ALL_SYNC_BITS are set. Wait a maximum of 100ms
// for this to happen.
uxReturn = xEventGroupSync( xEventBits, TASK_0_BIT, ALL_SYNC_BITS, xTicksToWait );
if( ( uxReturn & ALL_SYNC_BITS ) == ALL_SYNC_BITS )
{
// All three tasks reached the synchronisation point before the call
// to xEventGroupSync() timed out.
}
}
}
void vTask1( void *pvParameters )
{
for( ;; )
{
// Perform task functionality here.
// Set bit 1 in the event flag to note this task has reached the
// synchronisation point. The other two tasks will set the other two
// bits defined by ALL_SYNC_BITS. All three tasks have reached the
// synchronisation point when all the ALL_SYNC_BITS are set. Wait
// indefinitely for this to happen.
xEventGroupSync( xEventBits, TASK_1_BIT, ALL_SYNC_BITS, portMAX_DELAY );
// xEventGroupSync() was called with an indefinite block time, so
// this task will only reach here if the syncrhonisation was made by all
// three tasks, so there is no need to test the return value.
}
}
void vTask2( void *pvParameters )
{
for( ;; )
{
// Perform task functionality here.
// Set bit 2 in the event flag to note this task has reached the
// synchronisation point. The other two tasks will set the other two
// bits defined by ALL_SYNC_BITS. All three tasks have reached the
// synchronisation point when all the ALL_SYNC_BITS are set. Wait
// indefinitely for this to happen.
xEventGroupSync( xEventBits, TASK_2_BIT, ALL_SYNC_BITS, portMAX_DELAY );
// xEventGroupSync() was called with an indefinite block time, so
// this task will only reach here if the syncrhonisation was made by all
// three tasks, so there is no need to test the return value.
}
}
* \defgroup xEventGroupSync xEventGroupSync
* \ingroup EventGroup
*/
EventBits_t xEventGroupSync( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet, const EventBits_t uxBitsToWaitFor, TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
/**
* event_groups.h
*
EventBits_t xEventGroupGetBits( EventGroupHandle_t xEventGroup );
*
* Returns the current value of the bits in an event group. This function
* cannot be used from an interrupt.
*
* @param xEventGroup The event group being queried.
*
* @return The event group bits at the time xEventGroupGetBits() was called.
*
* \defgroup xEventGroupGetBits xEventGroupGetBits
* \ingroup EventGroup
*/
#define xEventGroupGetBits( xEventGroup ) xEventGroupClearBits( xEventGroup, 0 )
/**
* event_groups.h
*
EventBits_t xEventGroupGetBitsFromISR( EventGroupHandle_t xEventGroup );
*
* A version of xEventGroupGetBits() that can be called from an ISR.
*
* @param xEventGroup The event group being queried.
*
* @return The event group bits at the time xEventGroupGetBitsFromISR() was called.
*
* \defgroup xEventGroupGetBitsFromISR xEventGroupGetBitsFromISR
* \ingroup EventGroup
*/
EventBits_t xEventGroupGetBitsFromISR( EventGroupHandle_t xEventGroup ) PRIVILEGED_FUNCTION;
/**
* event_groups.h
*
void xEventGroupDelete( EventGroupHandle_t xEventGroup );
*
* Delete an event group that was previously created by a call to
* xEventGroupCreate(). Tasks that are blocked on the event group will be
* unblocked and obtain 0 as the event group's value.
*
* @param xEventGroup The event group being deleted.
*/
void vEventGroupDelete( EventGroupHandle_t xEventGroup ) PRIVILEGED_FUNCTION;
/* For internal use only. */
void vEventGroupSetBitsCallback( void *pvEventGroup, const uint32_t ulBitsToSet ) PRIVILEGED_FUNCTION;
void vEventGroupClearBitsCallback( void *pvEventGroup, const uint32_t ulBitsToClear ) PRIVILEGED_FUNCTION;
#if (configUSE_TRACE_FACILITY == 1)
UBaseType_t uxEventGroupGetNumber( void* xEventGroup ) PRIVILEGED_FUNCTION;
#endif
#ifdef __cplusplus
}
#endif
#endif /* EVENT_GROUPS_H */