Sean Schouten wrote :

> 
> There is another way; other than hard-coded memory 
> addressing? You would  make me happy by pointing
> me to an example. 

You could simply use the docs. Look up the RES assembler
directiv in the MPASM manual (or in the help file).

> > Also if TEMP_W is supposed to be
> > where W gets saved on interrupt, this will not work
> > on PICs  that have more than one bank.
> 
> Ah, why is that? 

Because you want to save W *without* making any
changes to STATUS (since that one will be save next, as-is).
And since you can not know which bank you're in when the INT fired,
you have to use un-banked memory. In the case of the F684,
that is h'70' - h'7F'. See the "data memory map" in the data sheet.

 
> How do I not use 'absolute-mode' in this case?...

In short :
- Add a "linker script" to your MPLAB project.
- Make the needed changes to the source to convert it
  from asb mode to reloc mode.

Not that you code of course will *work* in either mode,
but relocatable is the *prefered* way of writing code today.

> > ; Set OSC to 31kHz
> > > MOVLW 0x03
> > > MOVWF OSCCON
> > 
> > Doesn't this do more than just select the oscillator frequency?
> 
> No. 

Yes, it also select the source if the "system clock".
You are also writing a "1" to the LTS bit, which is read-only...


> > BSF INTCON, GIE ;Set the General Interrupt Enable bit to 1.
> > > BCF INTCON, RAIF ;Clear the PORTA interrupt flag.
> > 
> > This is out of order. Turning on GIE is the last thing you 
> > should do in the interrupt setup.
> 
> 
> I thought that GIE had to be turned on in order to enable 
> interrupts in general.

It is.
Just do it last in your INIT routine.


> Wouldn't it take multiple overflows to count to
> a second if I  switch my OSC up to 8Mhz?

Of course, that's the normal way to handle it, not
to lower the system clock as you do.

Jan-Erik.



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