PikeAero::CTimeBase Class Reference

#include <ctimebase.h>

Inheritance diagram for PikeAero::CTimeBase:

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Public Member Functions
	CTimeBase (CMachine::InterruptVector vector, TB_TypeDef *TBx, CMachine::ubit32 usec=0, CMachine::ubit8 prescaler=255)
virtual void	irq (CMachine::InterruptVector v)
	receive a hardware interrupt
bool	load (CMachine::ubit32 usec)
	set the timebase period in microseconds.
void	loadPrescaler (CMachine::ubit8 prescaler)
	load the prescaler
bool	running ()
	determin the running state of the time base. return true of time base is running.
void	start (CMachine::ubit32 usec)
void	start ()
	the timebase is not running until the start() method is called.
void	stop ()
	stop the time base but remember the period.
CMachine::ubit32	ticks ()
	at every time base period, a tick register is incremented.
virtual	~CTimeBase ()
Protected Member Functions
TB_TypeDef *	tb ()
Private Attributes
CMachine::ubit32	mMax
CMachine::ubit32	mMin
TB_TypeDef *	mTB
CMachine::ubit32	mTick
CMachine::ubit32	mUSec

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Detailed Description

Implements a Time Base object.

Author:

Michael Sharkey <mike@pikeaero.com>

Definition at line 31 of file ctimebase.h.

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Constructor & Destructor Documentation

PikeAero::CTimeBase::CTimeBase	(	CMachine::InterruptVector	vector,
		TB_TypeDef *	TBx,
		CMachine::ubit32	usec = 0,
		CMachine::ubit8	prescaler = 255
	)

stop counting.

calculate min and max timer values

select fMCLK as clock source.

enable interrupts from timer

Install self on interrupt vector chain.

Definition at line 24 of file ctimebase.cpp.

References PikeAero::TB_TypeDef::CR, PikeAero::CMachine::fpMCLK(), PikeAero::CMachine::installVectorIRQ(), load(), loadPrescaler(), mMax, mMin, PikeAero::TB_TypeDef::MR, PikeAero::TB_TypeDef::PR, stop(), tb(), TB_ECM, and TB_EE.

 : CObject()
 , mTB(TBx)
 , mTick(0)
 , mUSec(usec)
{
    /** stop counting. **/
    stop();

    /** calculate min and max timer values */
    mMin = tb()->PR * 1 * static_cast<CMachine::bit32>(CMachine::fpMCLK()) / 1000;
    mMax = tb()->PR * 65536 * static_cast<CMachine::bit32>(CMachine::fpMCLK()) / 1000;

    /** select fMCLK as clock source. */
    tb()->CR &= ~TB_EE;

    loadPrescaler(prescaler);
    load(usec);

    /** enable interrupts from timer */
    tb()->MR |= TB_ECM;

    /** Install self on interrupt vector chain. */
    CMachine::installVectorIRQ(vector,this);
}

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PikeAero::CTimeBase::~CTimeBase

(

)

[virtual]

stop counting.

Disable Interrupts

Remove self from interrupt vector

Definition at line 51 of file ctimebase.cpp.

References PikeAero::TB_TypeDef::MR, PikeAero::CMachine::removeVectorIRQ(), stop(), tb(), and TB_ECM.

{
    /** stop counting. **/
    stop();
    /** Disable Interrupts */
    tb()->MR &= ~TB_ECM;
    /** Remove self from interrupt vector */
    CMachine::removeVectorIRQ(this);
}

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Member Function Documentation

void PikeAero::CTimeBase::irq

(

CMachine::InterruptVector

v

)

[virtual]

receive a hardware interrupt

clear the End of Count flag

Increment the tick count

Reimplemented from PikeAero::CObject.

Reimplemented in PikeAero::CTimeBaseOneShot.

Definition at line 65 of file ctimebase.cpp.

References mTick, PikeAero::TB_TypeDef::SR, tb(), and TB_EC.

{
    if ( tb()->SR & TB_EC )
    {
        /** clear the End of Count flag **/
        tb()->SR &= ~TB_EC;
        /** Increment the tick count */
        ++mTick;
    }
}

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bool PikeAero::CTimeBase::load

(

CMachine::ubit32

usec

)

[inline]

set the timebase period in microseconds.

Parameters:

usec

specifies the timer period in microseconds or 0 to use the default full duration.

Returns:

true if sucessful, false if out of range (default period is then set). The time (us) needed to reach end of period is given by [ (TB->PR+1)*(TB->TV+1)*fMCLK/1000 == (period usecs) ]. For example, if fMCLK = 32MHz (31.25 nanosec) then the default (max) period is 256*65536*31.25/1000 = 524,288 usec. Minimum period (without altering prescaler) is 256*1*31.25/1000 = 8 usec.

set the default period

Definition at line 69 of file ctimebase.h.

References mMax, mMin, tb(), and PikeAero::TB_TypeDef::VR.

Referenced by CTimeBase(), PikeAero::CInputTimingToothCounter::irq(), and start().

        {
            if ( usec >= mMin && usec <= mMax )
            {
                tb()->VR = static_cast<CMachine::ubit16>(65536/(mMax/usec));
                return true;
            }
            /** set the default period */
            tb()->VR = 0xFFFF;
            return false;
        }

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void PikeAero::CTimeBase::loadPrescaler

(

CMachine::ubit8

prescaler

)

[inline]

load the prescaler

Definition at line 59 of file ctimebase.h.

References PikeAero::TB_TypeDef::PR, and tb().

Referenced by CTimeBase().

{ tb()->PR = prescaler; }

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bool PikeAero::CTimeBase::running

(

)

[inline]

determin the running state of the time base. return true of time base is running.

Definition at line 54 of file ctimebase.h.

References tb(), TB_ECM, and TB_SC.

{ return ( ( tb()->MR & TB_ECM )!=0 && ( tb()->CR & TB_SC )!=0 ); }

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void PikeAero::CTimeBase::start

(

CMachine::ubit32

usec

)

[inline]

Definition at line 42 of file ctimebase.h.

References load(), and start().

Referenced by start().

{ load(usec); start(); }

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void PikeAero::CTimeBase::start

(

)

[inline]

the timebase is not running until the start() method is called.

Returns:

true if sucessful, false if out of range.

Definition at line 41 of file ctimebase.h.

References PikeAero::TB_TypeDef::CR, tb(), and TB_SC.

Referenced by PikeAero::CInputTimingToothCounter::irq().

{ tb()->CR = TB_SC; }

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void PikeAero::CTimeBase::stop

(

)

[inline]

stop the time base but remember the period.

Definition at line 47 of file ctimebase.h.

References PikeAero::TB_TypeDef::CR, PikeAero::TB_TypeDef::SR, tb(), TB_EC, and TB_SC.

Referenced by CTimeBase(), PikeAero::CTimeBaseOneShot::irq(), PikeAero::CInputTimingToothCounter::irq(), and ~CTimeBase().

{ tb()->CR &= ~TB_SC; tb()->SR &= ~TB_EC; }

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TB_TypeDef* PikeAero::CTimeBase::tb

(

)

[inline, protected]

Definition at line 94 of file ctimebase.h.

References mTB.

Referenced by CTimeBase(), PikeAero::CTimeBaseOneShot::irq(), irq(), load(), loadPrescaler(), running(), start(), stop(), and ~CTimeBase().

{return mTB;}

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CMachine::ubit32 PikeAero::CTimeBase::ticks

(

)

[inline]

at every time base period, a tick register is incremented.

Returns:

the value of the tick register, i.e. number of time base periods elapsed.

Definition at line 85 of file ctimebase.h.

References mTick.

{return mTick;}

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Field Documentation

CMachine::ubit32 PikeAero::CTimeBase::mMax [private]

Definition at line 101 of file ctimebase.h.

Referenced by CTimeBase(), and load().

CMachine::ubit32 PikeAero::CTimeBase::mMin [private]

Definition at line 100 of file ctimebase.h.

Referenced by CTimeBase(), and load().

TB_TypeDef* PikeAero::CTimeBase::mTB [private]

Definition at line 97 of file ctimebase.h.

Referenced by tb().

CMachine::ubit32 PikeAero::CTimeBase::mTick [private]

Definition at line 98 of file ctimebase.h.

Referenced by irq(), and ticks().

CMachine::ubit32 PikeAero::CTimeBase::mUSec [private]

Definition at line 99 of file ctimebase.h.

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

• ctimebase.h
• ctimebase.cpp