csi_timer.c File Reference

Timer implementation form timeouts and time measuring. More...

#include "csi_timer.h"

Include dependency graph for csi_timer.c:

Functions
uint32_t	CsiTimerGetExpirationTime (TCsiTimer *pTimer)
	This function returns the absolut expiration time in millisecoonds. More...
uint32_t	CsiTimerGetMilliSec (void)
	Returns actual value of global millisecond timer. More...
void	CsiTimerInit (TCsiTimer *pTimer, uint32_t Period)
	Function CsiTimerInit() initialiszes a timer object. More...
uint8_t	CsiTimerIsExpired (TCsiTimer *pTimer)
	Check if a certain timer is expired or if it is still active. More...
void	CsiTimerRestart (TCsiTimer *pTimer)
	Initializes the timer with a new timestamp value. More...
void	CsiTimerSetTimestamp (TCsiTimer *pTimer, const uint32_t Period)
	Set timestamp value (expiration timer) of certain timer. More...
void	CsiTimerSetTimestampAndStartTime (TCsiTimer *pTimer, const uint32_t StartTime, const uint32_t Period)
	This function calculates the expiration time from a start time value and the timer period (expiration time = start time + period) More...

Detailed Description

Timer implementation form timeouts and time measuring.

Author

Uwe Kindler (UK)

Date

2009/08/27 The file implements a polling timer. The polling timer is intialized with a specific millisecond value and a timeout period. After this initialisation the application can check (poll) the timer for timeout.

Function Documentation

uint32_t CsiTimerGetExpirationTime

(

TCsiTimer *

pTimer

)

This function returns the absolut expiration time in millisecoonds.

Parameters

[in]

pTimer

The timer to query for expiration time

Returns

Timer expiration time in milliseconds

{
    return pTimer->Timestamp;
}

uint32_t CsiTimerGetMilliSec

(

void

)

Returns actual value of global millisecond timer.

Returns

An absolut time value in milliseconds

Referenced by CsiTimerIsExpired(), and CsiTimerSetTimestamp().

{
    //
    // CSI_HW_GET_TICK_COUNT is a macro that shouldbe defined by hardware
    // platform in Csi_plfabstr.h. The macro returns the actual value of
    // the global tick counter
    //
    return CSI_HW_GET_TICK_COUNT();
}

void CsiTimerInit	(	TCsiTimer *	pTimer,
		uint32_t	Period
	)

Function CsiTimerInit() initialiszes a timer object.

The function stores the dwPeriod value into the timer object pTimer.

Parameters

[in]	pTimer	The timer object to initialize
[in]	Period	The period of the timer

{
    pTimer->Timestamp = 0;
    pTimer->Period    = Period;
}

uint8_t CsiTimerIsExpired

(

TCsiTimer *

pTimer

)

Check if a certain timer is expired or if it is still active.

The function checks if the current time value is larger then the timer timestamp value. If the current time value is larger, then the timer is expired.

Parameters

[in]

pTimer

The timer to query

Return values

1	Timer expired
0	Timer not expired - active

{
    uint32_t TimeNow   = CsiTimerGetMilliSec();
    uint32_t Timestamp = (pTimer->Timestamp + 1);

    if (TimeNow > Timestamp)
    {
        if ((TimeNow - Timestamp) < 0x80000000)
        {
            return 1;
        }
        else
        {
            return 0;
        }
    }
    else // if (dwTimeNow  <= dwTimestamp)
    {
        if ((Timestamp - TimeNow) > 0x80000000)
        {
            return 1;
        }
        else
        {
            return 0;
        }
    } // if (time_now <= timestamp)
}

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void CsiTimerRestart

(

TCsiTimer *

pTimer

)

Initializes the timer with a new timestamp value.

The function calculates a new timestamp value. It uses the pTimer period for this calculation. The new timestamp value is the current timer plus the timer period.

Parameters

[in]

pTimer

Timer to restart

{
    CsiTimerSetTimestamp(pTimer, pTimer->Period);
}

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void CsiTimerSetTimestamp	(	TCsiTimer *	pTimer,
		const uint32_t	Period
	)

Set timestamp value (expiration timer) of certain timer.

The expiration time is the current time + the value in dwPeriod.

Parameters

[in]	pTimer	Timer to change
[in]	Period	The timer period (timestamp = current time + dwPeriod)

Referenced by CsiTimerRestart().

{
    uint32_t StartTime = CsiTimerGetMilliSec();

    CsiTimerSetTimestampAndStartTime(pTimer, StartTime, Period);
}

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void CsiTimerSetTimestampAndStartTime	(	TCsiTimer *	pTimer,
		const uint32_t	StartTime,
		const uint32_t	Period
	)

This function calculates the expiration time from a start time value and the timer period (expiration time = start time + period)

Parameters

[in]	pTimer	Timer to change
[in]	StartTime	The start time in milliseconds
[in]	Period	The timeout period of this timer in milliseconds

Referenced by CsiTimerSetTimestamp().

{
    pTimer->Timestamp = StartTime + Period;
    pTimer->Period    = Period;
}