Stacked Software Timer

Functions for creating, initializing, maintaining and handling a task timers. More...

Data Structures
struct	sysTimerStruc
	Struct for system timer maintenance. More...
struct	tskTimerStruc
	Struct for task timer maintenance. More...
struct	timerStruc
	Struct for timer maintenance. More...

Macros
#define	TMR_INVALID_TIME   (LifeTime)0xFFFFFFFFu
	Value for an invalid LifeTime.
#define	TMR_PIT_DELAY   (uint32_t)0x3u
	Delay compensation between PIT and TPM timers. More...
#define	MEM_OBJECTS_TMR   ((uint8_t)0x4u)
	Number of SyncEle that will be allocated by the Timer mechanism in its memory pool. More...

Typedefs
typedef uint16_t	WaitTime
	Time to wait for a Timer.
typedef uint32_t	SysTime
	Used to describe a systemtime.
typedef uint8_t	SysTicks
	Amount of SysTicks.
typedef uint16_t	TmrTime
	Used to describe the time of a software timer.
typedef uint32_t	LifeTime
	Used to describe time in the system as a timestamp.
typedef enum timerTypeEn	TimerType
	Enumeration of all the different types of software timers.
typedef struct sysTimerStruc	SysTimer
	Struct for system timer maintenance.
typedef struct tskTimerStruc	TskTimer
	Struct for task timer maintenance.
typedef struct timerStruc	Timer
	Struct for timer maintenance.

Enumerations

Functions
void	os_SCHEDULE (void)
	Schedules the next ready task according to its priority. More...
static RetCode	tmr_InsertSysTmrQ (TmrFktCall *sysFktTmr, LifeTime expires)
	Insert the given TmrFktCall object into the system timer queue according to its expiration time. More...
static RetCode	tmr_InsertTskTmrQ (PTskTCB tsk, LifeTime expires)
	Insert the given TskTCB object into the task timer queue according to its expiration time. More...
RetCode	tmr_INIT (void)
	Calibrate the PIT Timer periodically. More...
RetCode	tmr_setSysTimer (SysFktID fktID, TmrTime msToWait, uint8_t periodicity)
	Sets up a Timer to call a SysFkt corresponding to the given SysFktID as soon as the timer expires. More...
RetCode	tmr_setTskTimer (PTskTCB tsk, TmrTime msToWait)
	Sets up a Timer for a task and queues it into the Timer queue according to its WaitTime relative to the current PIT value. More...
void	tmr_SysTimerElapsed (void)
	Function to be called as soon as a system Timer expires. More...
void	tmr_TskTimerElapsed (void)
	Function to be called as soon as a task Timer expires. More...
RetCode	tmr_GiveUpOnTMR (PTskTCB const tsk)
	Forces the deletion of a task's Timer from the Timer queue and adjusts the queue accordingly. More...

Variables
SysFkt	sys_SysFkt []
	System function array to hold various kinds of system functions. System functions can be referenced by their index in this array.
static MemPoolID	memPoolID_TMR
	Memory Pool ID for the timer's memory pool. More...
static Timer	tskTMR
	The start node for the task Timer queue. More...
static Timer	sysTMR
	The start node for the system Timer queue. More...

Detailed Description

Functions for creating, initializing, maintaining and handling a task timers.

Macro Definition Documentation

#define MEM_OBJECTS_TMR   ((uint8_t)0x4u)

Number of SyncEle that will be allocated by the Timer mechanism in its memory pool.

Note

User Defined

#define TMR_PIT_DELAY   (uint32_t)0x3u

Delay compensation between PIT and TPM timers.

Returns

Delay value

Since the PIT and TPM timers are driven by different clock sources (BusClock for PIT; OSCERCLK for TPM) they might suffer from a desynchronization. In order to overcome this issue, a small delay is allowed.

Enumeration Type Documentation

enum timerTypeEn

Enumeration of all the different types of software timers.

Enumerator
SysTimerType	System software timer.
TskTimerType	Task software timer.
SysTickTimerType	System Tick software timer.

Function Documentation

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 tmr_GiveUpOnTMR

(

PTskTCB const

tsk

)

Forces the deletion of a task's Timer from the Timer queue and adjusts the queue accordingly.

Parameters

[in]

tsk

Pointer to the task's TskTcb

Returns

RetCode Return the success of the operation

If a task is destroyed, which still has a Timer, this Timer needs to be deleted from the queue and the timer might need to be adjusted accordingly.

Triggers the scheduler!

RetCode tmr_INIT

(

void

)

Calibrate the PIT Timer periodically.

Since the PIT timer is clocked by the Bus clock whereas the TPM module has various clock sources the two timers drift away from each other. To compensate this behavior the PIT timer is calibrated in intervals according to a TPM timer.

static RetCode tmr_InsertSysTmrQ ( TmrFktCall *  sysFktTmr, LifeTime  expires  )

static

Insert the given TmrFktCall object into the system timer queue according to its expiration time.

Parameters

[in]	sysFktTmr	Pointer to the TmrFktCall object to insert
[in]	expires	Expiration time

Returns

RetCode

RET_OK

RET_NOK

Note

Entries are sorted according to their ascending timer expiration.

static RetCode tmr_InsertTskTmrQ ( PTskTCB  tsk, LifeTime  expires  )

static

Insert the given TskTCB object into the task timer queue according to its expiration time.

Parameters

[in]	tsk	Pointer to the TskTCB object to insert
[in]	expires	Expiration time

Returns

RetCode

RET_OK

RET_NOK

Note

Entries are sorted according to their ascending timer expiration.

RetCode tmr_setSysTimer	(	SysFktID	fktID,
		TmrTime	msToWait,
		uint8_t	periodicity
	)

Sets up a Timer to call a SysFkt corresponding to the given SysFktID as soon as the timer expires.

Parameters

[in]	fktID	SysFktID of the function to call upon expiration
[in]	msToWait	Period of time to wait in ms
[in]	periodicity	Periodicity of the timer (if set to 1 the timer will reset itself)

Returns

RetCode

RET_OK

RET_NOK

RetCode tmr_setTskTimer	(	PTskTCB	tsk,
		TmrTime	msToWait
	)

Sets up a Timer for a task and queues it into the Timer queue according to its WaitTime relative to the current PIT value.

Parameters

[in]	tsk	Pointer to the task's TskTcb
[in]	msToWait	Period of time to wait in ms.

Returns

RetCode Return the success of the operation

Sets up a Timer for the given task and queues the Timer into the Timer queue. The Timer, which expires the earliest is always the start of the list. Might adjust the startTMRNode.

void tmr_SysTimerElapsed

(

void

)

Function to be called as soon as a system Timer expires.

Calls the system function and re-sets it according to its periodicty settings.

void tmr_TskTimerElapsed

(

void

)

Function to be called as soon as a task Timer expires.

Adjusts the TskEvtFlags and sets the task ready (if it is not waiting on any other event). Also maintains the Timer queue and automatically scans for more Timers to be expired. Resets the timer which triggers the next Timer.

Triggers the scheduler!

Variable Documentation

MemPoolID memPoolID_TMR

static

Memory Pool ID for the timer's memory pool.

Allocation requests for SyncEle for the Timer will be served from the memory pool corresponding to this MemPoolID.

Timer sysTMR

static

The start node for the system Timer queue.

Initialized to NULL.

Timer tskTMR

static

The start node for the task Timer queue.

Initialized to NULL.