cpp_freertos::EventGroup Class Reference

#include <event_groups.hpp>

Public Member Functions
	EventGroup ()
	EventGroup (StaticEventGroup_t *pxEventGroupBuffer)
virtual	~EventGroup ()
EventBits_t	ClearBits (const EventBits_t uxBitsToClear)
BaseType_t	ClearBitsFromISR (const EventBits_t uxBitsToClear)
EventBits_t	GetBits ()
EventBits_t	GetBitsFromISR ()
EventBits_t	SetBits (const EventBits_t uxBitsToSet)
BaseType_t	SetBitsFromISR (const EventBits_t uxBitsToSet, BaseType_t *pxHigherPriorityTaskWoken)
EventBits_t	Sync (const EventBits_t uxBitsToSet, const EventBits_t uxBitsToWaitFor, TickType_t xTicksToWait)
EventBits_t	WaitBits (const EventBits_t uxBitsToWaitFor, bool xClearOnExit, bool xWaitForAllBits, TickType_t xTicksToWait)

Protected Attributes
EventGroupHandle_t	handle

Detailed Description

Todo:

• document this class

Constructor & Destructor Documentation

EventGroup() [1/2]

EventGroup::EventGroup

(

)

Construct a Event Group

EventGroup() [2/2]

EventGroup::EventGroup

(

StaticEventGroup_t *

pxEventGroupBuffer

)

Construct a Event Group with static allocation

~EventGroup()

EventGroup::~EventGroup ( )

virtual

Our destructor

Member Function Documentation

ClearBits()

EventBits_t EventGroup::ClearBits

(

const EventBits_t

uxBitsToClear

)

Clear bits (flags) within an event group.

Parameters

uxBitsToClear

A bitwise value that indicates the bit or bits to clear in the event group.

Returns

The value of the event group before the specified bits were cleared.

ClearBitsFromISR()

BaseType_t EventGroup::ClearBitsFromISR

(

const EventBits_t

uxBitsToClear

)

Clear bits (flags) within an event group from ISR context.

Parameters

uxBitsToClear

A bitwise value that indicates the bit or bits to clear in the event group.

Returns

The value of the event group before the specified bits were cleared.

GetBits()

EventBits_t EventGroup::GetBits

(

)

Returns the current value of the event bits (event flags) in an event group.

Returns

The value of the event bits in the event group at the time EventGroup::GetBitsFromISR was called.

GetBitsFromISR()

EventBits_t EventGroup::GetBitsFromISR

(

)

Returns the current value of the event bits (event flags) in an event group from ISR context.

Returns

The value of the event bits in the event group at the time EventGroup::GetBitsFromISR was called.

SetBits()

EventBits_t EventGroup::SetBits

(

const EventBits_t

uxBitsToSet

)

Set bits (flags) within an event group.

Parameters

uxBitsToSet

A bitwise value that indicates the bit or bits to set in the event group.

Returns

The value of the event group at the time the call to EventGroup::SetBits returns

SetBitsFromISR()

BaseType_t EventGroup::SetBitsFromISR	(	const EventBits_t	uxBitsToSet,
		BaseType_t *	pxHigherPriorityTaskWoken
	)

Set bits (flags) within an event group from ISR context.

Parameters

uxBitsToSet	A bitwise value that indicates the bit or bits to set in the event group.
pxHigherPriorityTaskWoken	A bitwise value that indicates the bit or bits to set in the event group.

Returns

Calling this function will result in a message being sent to the RTOS daemon task. If the priority of the daemon task is higher than the priority of the currently running task (the task the interrupt interrupted) then *pxHigherPriorityTaskWoken will be set to true by EventGroupSetBitsFromISR, indicating that a context switch should be requested before the interrupt exits. For that reason *pxHigherPriorityTaskWoken must be initialised to false.

Sync()

EventBits_t EventGroup::Sync	(	const EventBits_t	uxBitsToSet,
		const EventBits_t	uxBitsToWaitFor,
		TickType_t	xTicksToWait
	)

Allow two or more tasks to use an event group to sync each other.

Parameters

uxBitsToSet	A bit mask that specifies the event bit, or event bits, to set 1 in the event group. The value of the event groups is updated by bitwise ORing the event group's existing value with the passed in uxBitsToSet.
uxBitsToWaitFor	The bit or bits to set in the event group before determining if (and possibly waiting for), all the bits specified by the uxBitsToWait parameter are set.
xTicksToWait	The maximum amount of time (specified in 'ticks') to wait for all the bits specified by the uxBitsToWaitFor parameter value to become set.

Returns

If EventGroup::Sync 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. If EventGroup::Sync returned because its timeout expired then not all the bits being waited for will be set.

WaitBits()

EventBits_t EventGroup::WaitBits	(	const EventBits_t	uxBitsToWaitFor,
		bool	xClearOnExit,
		bool	xWaitForAllBits,
		TickType_t	xTicksToWait
	)

Read bits within an RTOS event group, optionally entering the Blocked state (with a timeout) to wait for a bit or group of bits to become set.

Parameters

uxBitsToWaitFor	A bitwise value that indicates the bit or bits to test inside the event group.
xClearOnExit	If xClearOnExit is set to true then any bits set in the value passed as the uxBitsToWaitFor parameter will be cleared in the event group before EventGroup::WaitBits returns if EventGroup::WaitBits returns for any reason other than a timeout. The timeout value is set by the xTicksToWait parameter. If xClearOnExit is set to false then the bits set in the event group are not altered when the call to EventGroup::WaitBits returns.
xWaitForAllBits	is used to create either a logical AND test (where all bits must be set) or a logical OR test (where one or more bits must be set) as follows: @par If xWaitForAllBits is set to true then EventGroup::WaitBits will return when either all the bits set in the value passed as the uxBitsToWaitFor parameter are set in the event group or the specified block time expires. @par If xWaitForAllBits is set to false then EventGroup::WaitBits will return when any of the bits set in the value passed as the uxBitsToWaitFor parameter are set in the event group or the specified block time expires.
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.

Returns

The value of the event group at the time either the event bits being waited for became set, or the block time expired. The current value of the event bits in an event group will be different to the returned value if a higher priority task or interrupt changed the value of an event bit between the calling task leaving the Blocked state and exiting the EventGroup::WaitBits function. Test the return value to know which bits were set. If EventGroup::WaitBits returned because its timeout expired then not all the bits being waited for will be set. If EventGroup::WaitBits 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 because the xClearOnExit parameter was set to true.

Member Data Documentation

handle

EventGroupHandle_t cpp_freertos::EventGroup::handle

protected

FreeRTOS Event Group handle.

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The documentation for this class was generated from the following files:

• src/event_groups.hpp
• src/freertos-addon/c++/cevent_groups.cpp