> What about a friend method? There must be a way of specifying the ISR
> as a
> friend to the CTimer0 class, allowing it access to the private data.
>
> - Dean
Yes, making the interrupt a friend works exactly as I want. It solves the
problem of an interrupt not having a this pointer. The overhead seems
reasonable. The below uses my awkward de-mangler macro to produce the
interrupt declaration:
extern "C" void __vector_16(void)
__attribute__((alias("_ZN16CTimer0Interrupt11__vector_16Ev")));
void CTimer0Interrupt::__vector_16(void)
{
I will try tomorrow using Dean's much simpler macro.
Ron
//--------------------------------
class CTimer0
{
friend class CTimer0Interrupt;
public:
CTimer0();
~CTimer0();
bool GetOverflowFlag(void);
private:
void SetOverflowFlag(void);
private:
volatile bool mOverflowFlag;
CTimer0Interrupt mTimer0Interrupt;
};
//--------------------------------
class CTimer0Interrupt
{
public:
CTimer0Interrupt();
~CTimer0Interrupt();
private:
void TIMER0_OVF_vect(void) __attribute__ ((signal, __INTR_ATTRS));
};
The actual interrupt in the instance of CTimer0Interrupt is:
//---------------------------------------------------------------CLASS_ISR(C
Timer0Interrupt, 16, TIMER0_OVF_vect, 11)
{
TCNT0 = TIMER0_TIMEOUT; // restart the timeout
Timer0.SetOverflowFlag(); // tell our friend
}
The associated methods in the CTimer0 class are below. All this example
class had to do was provide an indication of an overflow event when
interrogated. Ie:
if (Timer0.GetOverflowFlag())
{
//---------------------------------------------------------------
bool CTimer0::GetOverflowFlag(void) // this is public
{
cli();
bool tempFlag = mOverflowFlag;
mOverflowFlag = false;
sei();
return tempFlag;
}
//---------------------------------------------------------------
void CTimer0::SetOverflowFlag(void) // this is private
{
mOverflowFlag = true;
}
The mOverflowFlag is of course volatile.
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