Yeah, that fixed the issue. That was a typo.

Best Regards,
Manu


On Wed, May 9, 2012 at 8:51 PM, Bob Ammerman <picram@roadrunner.com> wrote:
>
> Just a guess...
>
> If you misspell the name of the interrupt handler on the #pragma interrup=
t
> statement the compiler wouldn't know to end the routine with a RETFIE
> instead of a RETURN.
>
> -- Bob Ammerman
> RAm Systems
>
> ----- Original Message -----
> From: "Joe Wronski" <jwronski@stillwatereng.net>
> To: "Microcontroller discussion list - Public." <piclist@mit.edu>
> Sent: Wednesday, May 09, 2012 10:54 AM
> Subject: Re: [PIC]Interrupts with 18F4550 and C18
>
>
> > Without actually digging into the doc for the 18F part in the example
> > (18C452 ?), I can give some answers:
> > o Unconditional goto is due to limited program space in the interrupt
> > vector area.
> > o Retfie is generated by the compiler, probably due to the #pragma
> > interrupt directive. =A0Look at View->Disassembly Listing after buildin=
g.
> > o Can't speak to the GIE issue without further digging, but if it is
> > disabled by the interrupt mechanism, your cods should re-enable it,
> > unless it is implicitly done by the retfie.
> >
> > There should be no differences in the chip operation whether using C or
> > assembler. =A0Always look to the assembler produced by the compiler.
> >
> > Here is the interrupt exit code produced by C18 including the "missing"
> > retfie:
> >
> > =A0 00F2 =A0 =A052E5 =A0 =A0 MOVF 0xfe5, F, ACCESS
> > =A0 00F4 =A0 =A0CFE5 =A0 =A0 MOVFF 0xfe5, 0xfda
> > =A0 00F6 =A0 =A0FFDA =A0 =A0 NOP
> > =A0 00F8 =A0 =A00011 =A0 =A0 RETFIE 0x1
> >
> > Joe W
> >
> >
> >
> > On 5/9/2012 3:30 AM, Manu Abraham wrote:
> >> Hi,
> >>
> >> The C18 example states that an interrupt handler is to be defined thus=
:
> >> (in MCC18\examples\Interrupt\main.c)
> >>
> >> //--------------------------------------------------------------------=
--------
> >> // High priority interrupt vector
> >>
> >> #pragma code InterruptVectorHigh =3D 0x08
> >> void
> >> InterruptVectorHigh (void)
> >> {
> >> =A0 =A0_asm
> >> =A0 =A0 =A0goto InterruptHandlerHigh //jump to interrupt routine
> >> =A0 =A0_endasm
> >> }
> >>
> >>
> >> //--------------------------------------------------------------------=
--------
> >> // High priority interrupt routine
> >>
> >> #pragma code
> >> #pragma interrupt InterruptHandlerHigh
> >>
> >> void
> >> InterruptHandlerHigh ()
> >> {
> >> =A0 =A0if (INTCONbits.TMR0IF)
> >> =A0 =A0 =A0{ =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 //check for TMR0 overflow
> >> =A0 =A0 =A0 =A0INTCONbits.TMR0IF =3D 0; =A0 =A0 =A0 =A0 =A0 =A0//clear=
 interrupt flag
> >> =A0 =A0 =A0 =A0Flags.Bit.Timeout =3D 1; =A0 =A0 =A0 =A0 =A0 =A0//indic=
ate timeout
> >> =A0 =A0 =A0 =A0LATBbits.LATB0 =3D !LATBbits.LATB0; //toggle LED on RB0
> >> =A0 =A0 =A0}
> >> }
> >>
> >>
> >> But I can't seem to figure out why that INTCONbits.GIEH is disabled
> >> after once it has run through the handler. In asm, the Global Interrup=
t
> >> handler is enabled after a retfie, but with C18 and the 18F4550, this
> >> doesn't seem to be the case, I do need a retfie as follows, for the
> >> interrupt to be re enabled. Any idea why it is thus ?
> >>
> >> Additionally, I have this question, the ISR is unconditionally jumping
> >> to
> >> another function. Especially in an ISR, I can't really reason why that
> >> would be a good practice ? =A0(Although I can assume that the function=
s
> >> would expand to labels in asm. But still doesn't explain the missing
> >> retfie)
> >>
> >>
> >>
> >> void low_isr(void)
> >> {
> >> =A0 =A0 =A0if ((PIE1bits.TMR2IE =3D=3D 1)&& =A0(PIR1bits.TMR2IF =3D=3D=
 1)) {
> >> =A0 =A0 =A0 =A0 =A0PIR1bits.TMR2IF =3D 0;
> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 DisplayDigit(segment, display[segment]=
);
> >> =A0 =A0 =A0}
> >> =A0 =A0 =A0_asm
> >> =A0 =A0 =A0 =A0 =A0retfie 0
> >> =A0 =A0 =A0_endasm
> >> }
> >>
> >> #pragma code low_vector =3D 0x18
> >> void low_vector (void)
> >> {
> >> =A0 =A0 =A0_asm goto low_isr _endasm
> >> }
> >>
> >> void init_timer2(void)
> >> {
> >> =A0 =A0 =A0OpenTimer2(TIMER_INT_ON& =A0T2_PS_1_4& =A0T2_POST_1_1);
> >> =A0 =A0 =A0 PR2 =3D 223;
> >> =A0 =A0 =A0RCONbits.IPEN =A0 =A0=3D 1; /* Interrupt priority enable */
> >> =A0 =A0 =A0 =A0 =A0IPR1bits.TMR2IP =A0 =A0=3D 0; /* TMR2 Low priority =
*/
> >> =A0 =A0 =A0 INTCONbits.GIEL =3D 1;
> >> =A0 =A0 =A0 =A0 INTCONbits.GIEH =3D 1;
> >> }
> >>
> >> void main()
> >> {
> >> =A0 =A0 =A0TRISD =3D 0;
> >> =A0 =A0 =A0TRISC =3D 0;
> >> =A0 =A0 =A0init_timer2();
> >>
> >> =A0 =A0 =A0while (1) {
> >>
> >> =A0 =A0 =A0 =A0 =A0}
> >> }
> >>
> >> Thanks,
> >> Manu
> >
> > --
> > http://www.piclist.com PIC/SX FAQ & list archive
> > View/change your membership options at
> > http://mailman.mit.edu/mailman/listinfo/piclist
>
> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist

--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.