Functions for creating, maintaining and handling tasks. More...

Data Structures
struct	tskMailBox
	Task mailbox for messaging services. More...

struct	advTskPrio_struc
	Contains the TskPrio visible to the system and the real TskPrio. More...

struct	tskTCB
	Task Control Block. More...

Macros
#define	MAX_TASKS NR_OF_TSKS
	Maximum number of tasks in the system. More...

#define	TSK_ID_IDLE ((TskID)0x0u)
	Reserved TskID for the IDLE Task. More...

#define	TSK_ID_NO_TSK TSK_ID_IDLE
	Reserved ID for no task. More...

#define	TSK_GETSTATE(pTsk) (TskState)(pTsk->tskState)
	Given a pointer to a TskTCB, retrieve the current state of the task.

#define	TSK_STATE_IS_ERROR(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_ERROR)
	Evaluate if the task is in an error state.

#define	TSK_STATE_IS_ACTIVE(pTsk) (TskState)(TSK_GETSTATE(pTsk) & TSK_STATE_ACTIVE)
	Evaluate if the task is in an active state.

#define	TSK_STATE_IS_ACTIVE_RUNNING(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_ACTIVE_RUNNING )
	Evalutate if the task is currently in the ACTIVE_RUNNING state.

#define	TSK_STATE_IS_ACTIVE_SUSPENDED(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_ACTIVE_SUSPENDED )
	Evalutate if the task is currently in the ACTIVE_SUSPENDED state.

#define	TSK_STATE_IS_ACTIVE_READY(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_ACTIVE_READY )
	Evalutate if the task is currently in the ACTIVE_READY state.

#define	TSK_STATE_IS_ACTIVE_CRITSEC(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_ACTIVE_CRITSEC )
	Evalutate if the task is currently in the ACTIVE_CRITSEC state. More...

#define	TSK_STATE_IS_WAITING(pTsk) (TskState)(TSK_GETSTATE(pTsk) & TSK_STATE_WAITING)
	Evalutate if the task is in a waiting state.

#define	TSK_STATE_IS_WAITING_TMR(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_WAITING_TMR)
	Evalutate if the task is in a waiting state, waiting for a software timer to expire.

#define	TSK_STATE_IS_WAITING_MSGRCV(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_WAITING_MSGRCV)
	Evalutate if the task is in a waiting state, waiting for a message to be received.

#define	TSK_STATE_IS_WAITING_MSGSND(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_WAITING_MSGSND)
	Evalutate if the task is in a waiting state, waiting for a message to be send.

#define	TSK_STATE_IS_WAITING_EVT(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_WAITING_EVT)
	Evalutate if the task is in a waiting state, waiting for an event or a group of events.

#define	TSK_STATE_IS_WAITING_SEM(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_WAITING_SEM)
	Evalutate if the task is in a waiting state, waiting for an occupied semaphore.

#define	TSK_STATE_IS_WAITING_MNTR(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_WAITING_MNTR)
	Evalutate if the task is in a waiting state, waiting for a currently blocked monitor.

#define	TSK_STATE_IS_UNINIT(pTsk) (TskState)(TSK_GETSTATE(pTsk) & TSK_STATE_UNINIT)
	Evalutate if the task is in an uninitialized state. More...

#define	TSK_STATE_IS_UNINIT_UNINIT(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_UNINIT_UNINIT)
	Evalutate if the task has not yet been initialized correctly.

#define	TSK_STATE_IS_UNINIT_FAILED(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_UNINIT_FAILED)
	Evalutate if the task is in an uninitialized state due to a system failure.

#define	TSK_STATE_IS_UNINIT_ENDED(pTsk) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_UNINIT_ENDED)
	Evalutate if the task is in an uninitialized state because it finished its execution.

#define	NR_OF_TSKS ((uint8_t)0x4u)
	Number of tasks in the system. More...

#define	TSK_PRIO_LEVELS_NR ((uint8_t)0xFu)
	Number of available priority levels in the system. More...

Typedefs
typedef uint8_t	TskID
	Task identification number (ID).

typedef uint8_t	TskPrioLvl
	Used to set the size of the task priorities.

typedef uint8_t	tskStateT
	Used to set the size of the task states.

typedef FktCall	TskStartAddr
	function pointer to a task's function with no arguments and no return.

typedef FktCall	TskEndAddr
	function pointer to a function which shall be called if a task finishes its execution.

typedef enum tskPrio	TskPrio
	Task priority level.

typedef enum tskState	TskState
	Possible states of tasks. More...

typedef enum tskSettings	TskSettings
	Settings of a task...

typedef struct tskMailBox	TskMB
	Task mailbox for messaging services. More...

typedef struct advTskPrio_struc	AdvTskPrio
	Contains the TskPrio visible to the system and the real TskPrio. More...

typedef struct tskTCB	TskTCB
	Task Control Block. More...

Enumerations

Functions
void	os_SCHEDULE (void)
	Schedules the next ready task according to its priority. More...

RetCode	tsk_tskInit (const TskID tskID, const TskStartAddr const strtAddr, const TskEndAddr const endAddr, const StackSize stkSze)
	Creates a task according to the provided input parameters. More...

RetCode	os_IDLETskInit (const TskStartAddr const strtAddr)
	Creates the IDLE Task. More...

RetCode	tsk_tskDestroy (TskTCB *const tsk)
	Destroy the given task. More...

RetCode	tsk_ClrEvt (PTskTCB const tsk, PSyncEle const syncEle)
	Clear the event that currently blocks the task. More...

RetCode	tsk_SetEvt (PTskTCB const tsk, PSyncEle const syncEle)
	Set the event described by syncEle for the specified task. More...

RetCode	tsk_SetInactive (PTskTCB const tsk, TskState tskInactvState)
	Set the specified task inactive, remove from active wait queue and set the specified new task state. More...

RetCode	tsk_ChngePrio (PTskTCB const tsk, const TskPrio newTskPrio)

Variables
BitsOSFlags	gOS_FLAGS
	Flags used for maintaining the OS. More...

TskTCB *	p_cur_tsk_tcb
	Pointer to currently running task's tskTCB. More...

PTskTCB const	pIDLETsk = &( tsk_AR[0] )
	Constant pointer to the IDLE Task's tskTCB. More...

PTskTCB	pIDLETsk
	Constant pointer to the IDLE Task's tskTCB. More...

Detailed Description

Functions for creating, maintaining and handling tasks.

Macro Definition Documentation

#define MAX_TASKS NR_OF_TSKS

Maximum number of tasks in the system.

The Maximum number of tasks in the system is influenced by the amount of heap available.

#define NR_OF_TSKS ((uint8_t)0x4u)

Number of tasks in the system.

Note: User Defined

#define TSK_ID_IDLE ((TskID)0x0u)

Reserved TskID for the IDLE Task.

TskID 0 is reserved for the IDLE Task to ensure it always has the same ID

Warning: NO TASK EXCEPT THE IDLE TASK SHALL HAVE THIS ID!

#define TSK_ID_NO_TSK TSK_ID_IDLE

Reserved ID for no task.

TSK_ID_NO_TSK is a specially reserved TskID to indicate that there is no task.

Warning: NO TASK SHALL HAVE THIS ID!

#define TSK_PRIO_LEVELS_NR ((uint8_t)0xFu)

Number of available priority levels in the system.

Note: User defined.; Maximum 256, minimum 2

#define TSK_STATE_IS_ACTIVE_CRITSEC ( pTsk ) (TskState)(TSK_GETSTATE(pTsk) == TSK_STATE_ACTIVE_CRITSEC )

Evalutate if the task is currently in the ACTIVE_CRITSEC state.

The task is currently running and also within a critical section.

#define TSK_STATE_IS_UNINIT ( pTsk ) (TskState)(TSK_GETSTATE(pTsk) & TSK_STATE_UNINIT)

Evalutate if the task is in an uninitialized state.

Warning: IF THE TASK IS UNINITIALIZED, DO NOT ATTEMPT TO FORCEFULLY RUN A TASK.

Typedef Documentation

typedef struct advTskPrio_struc AdvTskPrio

Contains the TskPrio visible to the system and the real TskPrio.

Each task has a visible TskPrio which represents the priority the task currently has as seen by the system. Additionally each task saves its actual TskPrio for further retrieval.

typedef struct tskMailBox TskMB

Task mailbox for messaging services.

Mailbox to keep track of received messages and their sources. Mailbox are arranged in a single linked list. Hence a task can have multiple mailboxes of the same or different sources.

typedef enum tskState TskState

Possible states of tasks.

State	Mask (bits)
TSK_STATE_ERROR	0000 0000
TSK_STATE_ACTIVE	0001 0000
TSK_STATE_ACTIVE_RUNNING	0001 0001
TSK_STATE_ACTIVE_SUSPENDED	0001 0010
TSK_STATE_ACTIVE_READY	0001 0100
TSK_STATE_ACTIVE_CRITSEC	0001 1000
TSK_STATE_WAITING	0110 0000
TSK_STATE_WAITING_MSGNG	0010 0000
TSK_STATE_WAITING_MSGRCV	0010 0001
TSK_STATE_WAITING_MSGSND	0010 0010
TSK_STATE_WAITING_SYNC	0100 0000
TSK_STATE_WAITING_TMR	0100 0001
TSK_STATE_WAITING_EVT	0100 0010
TSK_STATE_WAITING_SEM	0100 0100
TSK_STATE_WAITING_MNTR	0100 1000
TSK_STATE_UNINIT	1000 0000
TSK_STATE_UNINIT_UNINIT	1000 0001
TSK_STATE_UNINIT_FAILED	1000 0010
TSK_STATE_UNINIT_ENDED	1000 1000

typedef struct tskTCB TskTCB

Task Control Block.

The Task Control block contains information about the task and its state. In addition the TCB contains a XORed pointer to the next and previous task queue entry.

Enumeration Type Documentation

enum tskPrio

Task priority level.

Enumerator
TSK_PRIO_ERROR	Pseudo priority level indicating an error.
TSK_PRIO_LOWEST	TSK_PRIO_LOWEST.
TSK_PRIO_LOWER	TSK_PRIO_LOWER.
TSK_PRIO_LOW	TSK_PRIO_LOW.
TSK_PRIO_MED	TSK_PRIO_MED.
TSK_PRIO_ABOVMED	TSK_PRIO_ABOVMED.
TSK_PRIO_HIG	TSK_PRIO_HIG.
TSK_PRIO_HIGHER	TSK_PRIO_HIGHER.
TSK_PRIO_HIGHEST	TSK_PRIO_HIGHEST.
TSK_PRIO_ULT	TSK_PRIO_ULT.
TSK_PRIO_IDLE	Utmost highest priority is unique to the IDLE Task to ensure that it is always the start of the list regardless of the other task's priority levels.

enum tskSettings

Settings of a task...

Enumerator
TskSet_NONE	NO SETTINGS.
TskSet_Periodic	keep task context
TskSet_OneShot	delete after execution
TskSet_DUMMY_0	TskSet_DUMMY_0.
TskSet_DUMMY_1	TskSet_DUMMY_1.
TskSet_DUMMY_2	TskSet_DUMMY_2.
TskSet_DUMMY_3	TskSet_DUMMY_3.
TskSet_DUMMY_4	TskSet_DUMMY_4.
TskSet_DUMMY_5	TskSet_DUMMY_5.

enum tskState

Possible states of tasks.

State	Mask (bits)
TSK_STATE_ERROR	0000 0000
TSK_STATE_ACTIVE	0001 0000
TSK_STATE_ACTIVE_RUNNING	0001 0001
TSK_STATE_ACTIVE_SUSPENDED	0001 0010
TSK_STATE_ACTIVE_READY	0001 0100
TSK_STATE_ACTIVE_CRITSEC	0001 1000
TSK_STATE_WAITING	0110 0000
TSK_STATE_WAITING_MSGNG	0010 0000
TSK_STATE_WAITING_MSGRCV	0010 0001
TSK_STATE_WAITING_MSGSND	0010 0010
TSK_STATE_WAITING_SYNC	0100 0000
TSK_STATE_WAITING_TMR	0100 0001
TSK_STATE_WAITING_EVT	0100 0010
TSK_STATE_WAITING_SEM	0100 0100
TSK_STATE_WAITING_MNTR	0100 1000
TSK_STATE_UNINIT	1000 0000
TSK_STATE_UNINIT_UNINIT	1000 0001
TSK_STATE_UNINIT_FAILED	1000 0010
TSK_STATE_UNINIT_ENDED	1000 1000

Enumerator
TSK_STATE_ERROR	Error state.
TSK_STATE_ACTIVE	Active task states.
TSK_STATE_ACTIVE_RUNNING	Task is currently running.
TSK_STATE_ACTIVE_SUSPENDED	Task was preempted, hence it is suspended.
TSK_STATE_ACTIVE_READY	Task is ready to be run.
TSK_STATE_ACTIVE_CRITSEC	Task is running in a critical section.
TSK_STATE_WAITING_MSGNG	Task messaging waiting states.
TSK_STATE_WAITING_MSGRCV	Task is waiting for a message to be published.
TSK_STATE_WAITING_MSGSND	Task is waiting for its message to be received.
TSK_STATE_WAITING_SYNC	Task synchronization waiting states.
TSK_STATE_WAITING_TMR	Task is waiting for a timer.
TSK_STATE_WAITING_EVT	Task is waiting for an event.
TSK_STATE_WAITING_SEM_BIN	Task is waiting for a binary semaphore.
TSK_STATE_WAITING_SEM_CNT	Task is waiting for a coutning semaphore.
TSK_STATE_WAITING_MTX	Task is waiting for a mutex.
TSK_STATE_WAITING_MNTR	Task is waiting for a monitor.
TSK_STATE_WAITING	Common task waiting states.
TSK_STATE_UNINIT	Task is uninitialized.
TSK_STATE_UNINIT_UNINIT	Task has not yet been initialized.
TSK_STATE_UNINIT_FAILED	Task is uninitialized due to a system failure.
TSK_STATE_UNINIT_ENDED	Task is uninitialized, because it finished its execution.

Function Documentation

RetCode os_IDLETskInit ( const TskStartAddr const strtAddr )

Creates the IDLE Task.

Parameters

[in] strtAddr Address of the IDLE Task's function

Returns: RetCode Return the success of the operation

Create the IDLE Task and provide its tskTCB with information.

void os_SCHEDULE ( void )

Schedules the next ready task according to its priority.

The task queue is scanned until a task ready to run is found. The queue is sorted according to the tasks' priority beforehand.

Postcondition: p_nxt_tsk_tcb A pointer to the chosen task's tskTCB is stored to this global variable.; If the next task does not equal the current task a context switch is initiated by setting PendSV to pending

RetCode tsk_ChngePrio	(	PTskTCB const	tsk,
		const TskPrio	newTskPrio
	)

Parameters

[in]	tsk	Pointer to the TskTCB of the task to change the priority of
[in]	newTskPrio	TskPrio to set the task to

Returns: RetCode; RET_OK; RET_NOK

RetCode tsk_ClrEvt	(	PTskTCB const	tsk,
		PSyncEle const	syncEle
	)

Clear the event that currently blocks the task.

Parameters

[in]	tsk	Pointer to the TskTCB to clear the event for
[in]	syncEle	Pointer to the SyncEle set up for the event

Returns: RetCode; RET_OK; RET_NOK

Precondition: Task must be inactive and blocked by the event specified by syncEle.

Postcondition: Task is put into the active task list.

RetCode tsk_SetEvt	(	PTskTCB const	tsk,
		PSyncEle const	syncEle
	)

Set the event described by syncEle for the specified task.

Parameters

[in]	tsk	Pointer to the TskTCB to set the event for
[in]	syncEle	Pointer to the SyncEle set up for the event

Returns: RetCode; RET_OK; RET_NOK

Precondition: Task must be active and in the active task list.

Postcondition: Task is set inactive and taken out of the active task list.

RetCode tsk_SetInactive	(	PTskTCB const	tsk,
		TskState	tskInactvState
	)

Set the specified task inactive, remove from active wait queue and set the specified new task state.

Parameters

[in]	tsk	Pointer to the TskTCB to set inactive
[in]	tskInactvState	State to set the task to

Returns: RetCode; RET_OK; RET_NOK

RetCode tsk_tskDestroy ( TskTCB *const tsk )

Destroy the given task.

Parameters

[in] tsk Pointer to the TskTCB of the task to be destroyed

Returns: RetCode Return the success of the operation

Release all resources used by the task and delete it from the queue.

This does not trigger the scheduler!

RetCode tsk_tskInit	(	const TskID	tskID,
		const TskStartAddr const	strtAddr,
		const TskEndAddr const	endAddr,
		const StackSize	stkSze
	)

Creates a task according to the provided input parameters.

Parameters

[in]	tskID	TskID of the task to be created
[in]	strtAddr	Address of the task's function
[in]	endAddr	Optional address of a function to which the task shall return to after its execution (provide NULL for default behavior)
[in]	stkSze	desired size of the task's stack

Returns: RetCode Return the success of the operation

Creates a task by allocating space for its tskTCB and filling it with the provided and computed informations. Also allocates the stack for the task.

Note: Task is not activated yet!

Variable Documentation

BitsOSFlags gOS_FLAGS

Flags used for maintaining the OS.

Contains various flags for the operation of the OS.

might be obsolete

TskTCB* p_cur_tsk_tcb

Pointer to currently running task's tskTCB.

To keep track of the currently running task this pointer stores it. Is set to NULL when the currently running task is ended/killed, which is then acknowledged by the context switch (No saving of the current task's context).

Initialized to NULL

pIDLETsk

Constant pointer to the IDLE Task's tskTCB.

Since the IDLE Task is not allocated dynamically its location in the memory will not change during runtime. This Pointer is used to always reference the IDLE Task and thus the start of the list containing all tasks in the System.

Initialized to the address of the IDLE Task's tskTCB.

PTskTCB const pIDLETsk = &( tsk_AR[0] )

Constant pointer to the IDLE Task's tskTCB.

Since the IDLE Task is not allocated dynamically its location in the memory will not change during runtime. This Pointer is used to always reference the IDLE Task and thus the start of the list containing all tasks in the System.

Initialized to the address of the IDLE Task's tskTCB.

Data Structures

Macros

Typedefs

Enumerations

Functions

Variables

Detailed Description

Macro Definition Documentation

Typedef Documentation

Enumeration Type Documentation

Function Documentation

Variable Documentation