ncr89105timer.c

IXP425的BSP代码

        *NCR89C105_COUNTER_1_CR = 1;      /* disable timer */
        sysAuxClkRunning = FALSE;
        }
    }

/***************************************************************************
*
* sysAuxClkEnable - turn on auxiliary clock interrupts
*
* This routine enables auxiliary clock interrupts.
*
* RETURNS: N/A
*
* SEE ALSO: sysAuxClkDisable(), sysAuxClkRateSet()
*/

void sysAuxClkEnable (void)
    {
    if (!sysAuxClkRunning)
        {
	*NCR89C105_COUNTER_1_CR = 0;		/* enable timer */
	*NCR89C105_LIMIT_1      = (1000000 / auxClkTicksPerSecond) << 10;

        sysAuxClkRunning  = TRUE;
        }
    }

/***************************************************************************
*
* sysAuxClkRateGet - get the auxiliary clock rate
*
* This routine returns the interrupt rate of the auxiliary clock.
*
* RETURNS: The number of ticks per second of the auxiliary clock.
*
* SEE ALSO: sysAuxClkEnable(), sysAuxClkRateSet()
*/

int sysAuxClkRateGet (void)
    {
    return (auxClkTicksPerSecond);
    }

/***************************************************************************
*
* sysAuxClkRateSet - set the auxiliary clock rate
*
* This routine sets the interrupt rate of the auxiliary clock.  It does not
* enable auxiliary clock interrupts.
*
* RETURNS: OK, or ERROR if the tick rate is invalid or the timer cannot be set.
*
* SEE ALSO: sysAuxClkEnable(), sysAuxClkRateGet()
*/

STATUS sysAuxClkRateSet
    (
    int ticksPerSecond      /* number of clock interrupts per second */
    )
    {
    if (ticksPerSecond < AUX_CLK_RATE_MIN || ticksPerSecond > AUX_CLK_RATE_MAX)
	return (ERROR);

    auxClkTicksPerSecond = ticksPerSecond;

    if (sysAuxClkRunning)
	{
	sysAuxClkDisable ();
	sysAuxClkEnable ();
	}

    return (OK);
    }


#ifdef INCLUDE_TIMESTAMP

/**************************************************************************
*
* sysTimestampInt - timestamp timer interrupt handler
*
* This routine handles the timestamp timer interrupt.   A user routine is
* called, if one was connected by sysTimestampConnect().
*
* RETURNS: N/A
*
* SEE ALSO: sysTimestampConnect()
*/

LOCAL void sysTimestampInt (void)
    {
    /* acknowledge the timer rollover interrupt here */

    if (sysTimestampRoutine != NULL)     /* call user-connected routine */
        (*sysTimestampRoutine) (sysTimestampArg);

    sysAuxClkAck ();
    }

/**************************************************************************
*
* sysTimestampConnect - connect a user routine to a timestamp timer interrupt
*
* This routine specifies the user interrupt routine to be called at each
* timestamp timer interrupt.  
*
* RETURNS: OK, or ???? ERROR if sysTimestampInt() interrupt service routine is 
* not used.
*/

STATUS sysTimestampConnect
    (
    FUNCPTR routine, /* routine called at each timestamp timer interrupt */
    int arg          /* argument with which to call routine */
    )
    {
    sysTimestampConnected = TRUE;
    sysTimestampRoutine = routine;
    sysTimestampArg = arg;
    return (OK);
    }

/**************************************************************************
*
* sysTimestampEnable - enable a timestamp timer interrupt
*
* This routine enables timestamp timer interrupts and resets the counter.
*
* RETURNS: OK, or ERROR if the timestamp timer cannot be enabled.
*/

STATUS sysTimestampEnable (void)
    {
    if (!sysTimestampRunning)
	{
        (void) intConnect ((VOIDFUNCPTR *) INUM_TO_IVEC  (INT_VEC_AUX_CLOCK),
		       (VOIDFUNCPTR) sysTimestampInt, NULL);

        /* Put the processor timer in timer mode */

        *NCR89C105_COUNTER_1_CR = 0;

        /* Set the limit register (not really used though, just for safety */

        *NCR89C105_LIMIT_1 = 0x7ffffe00;

        sysTimestampRunning = TRUE;
	}

    return (OK);
    }


/**************************************************************************
*
* sysTimestampDisable - disable a timestamp timer interrupt
*
* This routine disables the timestamp timer.  It does not directly disable
* interrupts.  However, the tick counter does not increment once the 
* timestamp timer is disabled, thus, interrupts are no longer generated.
* This routine merely resets the timer counter.
*
* RETURNS: OK, or ERROR if the timestamp timer cannot be disabled.
*/

STATUS sysTimestampDisable (void)
    {
    if (sysTimestampRunning)
	{

	/* Stop the timer to count */

        *NCR89C105_COUNTER_1_CR = 1;

	sysTimestampRunning = FALSE;
	}

    return (OK);
    }


/**************************************************************************
*
* sysTimestampPeriod - get the period of a timestamp timer 
*
* This routine gets the period of the timestamp timer, in ticks.  The
* period, or terminal count, is the number of ticks to which the timestamp
* timer counts before rolling over and restarting the counting process.
*
* RETURNS: The period of the timestamp timer in counter ticks.
*/

UINT32 sysTimestampPeriod (void)
    {
    /* 
     * Return the timestamp timer period here.
     * The highest period (maximum terminal count) should be used so
     * that rollover interrupts are kept to a minimum.
     *
     */

    return (0x1fffff);
    }


/**************************************************************************
*
* sysTimestampFreq - get a timestamp timer clock frequency
*
* This routine gets the frequency of the timer clock, in ticks per 
* second.  The rate of the timestamp timer is set explicitly by the 
* hardware and typically cannot be altered.
*
* RETURNS: The timestamp timer clock frequency, in ticks per second.
*/

UINT32 sysTimestampFreq (void)
    {
    UINT32 timerFreq;

    /*
     * Return the timestamp tick output frequency here.
     * This value can be determined from the following equation:
     *     timerFreq = clock input frequency / prescaler
     *
     * When possible, read the clock input frequency and prescaler values
     * directly from chip registers.
     */

    /* (1000000/0.5) = 2000000 counter increments every 500ns */

    timerFreq = USER_TIMER_FREQ;

    return (timerFreq);
    }


/**************************************************************************
*
* sysTimestamp - get a timestamp timer tick count
*
* This routine returns the current value of the timestamp timer tick counter.
* The tick count can be converted to seconds by dividing it by the return of
* sysTimestampFreq().
*
* This routine should be called with interrupts locked.  If interrupts are
* not locked, sysTimestampLock() should be used instead.
*
* RETURNS: The current timestamp timer tick count.
*
* SEE ALSO: sysTimestampFreq(), sysTimestampLock()
*/

UINT32 sysTimestamp (void)
    {
    unsigned long countValueLsw;

    countValueLsw = (*NCR89C105_COUNTER_1);

    countValueLsw = countValueLsw >> USER_TIMER_LSW_SHIFT;

    /* return the timestamp timer tick count here */

    return (countValueLsw);
    }


/**************************************************************************
*
* sysTimestampLock - lock interrupts and get the timestamp timer tick count
*
* This routine locks interrupts when the tick counter must be stopped 
* in order to read it or when two independent counters must be read.  
* It then returns the current value of the timestamp timer tick
* counter.
* 
* The tick count can be converted to seconds by dividing it by the return of
* sysTimestampFreq().
*
* If interrupts are already locked, sysTimestamp() should be
* used instead.
*
* RETURNS: The current timestamp timer tick count.
*
* SEE ALSO: sysTimestampFreq(), sysTimestamp()
*/

UINT32 sysTimestampLock (void)
    {
    unsigned long countValueLsw;

    countValueLsw = (*NCR89C105_COUNTER_1);

    countValueLsw = countValueLsw >> USER_TIMER_LSW_SHIFT;

    /* return the timestamp timer tick count here */

    return (countValueLsw);
    }

#endif   /* INCLUDE_TIMESTAMP */