> Kevin Rhoades <PICLIST@MITVMA.MIT.EDU> wrote:
>
> > In the include files (MPASM) for the '84 it lists:
> >
> >         TRISA EQU H'0085'
> >
> > My question is this, why does the file assign the value of 85 to be
> > used when addressing the TRISA register if the msb is not even used?
> > Would not a value of 05 give the same result?
>
> Kevin:
>
> Yes.  In fact, if you use the include file and write:
>
>     MOVWF   TRISA
>
> MPASM will generate code that's equivalent to "MOVWF 005H".  On top
> of that, it'll give you a warning that the operand was truncated.
>
> Given this, it seems silly to use the "085H" definition.  Using that
> definition, however,
>
>     1.  more accurately depicts what your code's doing, making it
>         more self-documenting,
>     2.  allows simulators and emulators to track the TRISA
>         register, and
>     3.  builds character.
>
> -Andy
>

and...

      4.  you can write:

          MOVLW   TRISA
          MOVWF   FSR

          to access the register indirectly.

___Bob