> Please ignore the question, I discovered that if the a/d value was 255,
the
> program would go off the end of my lookup table - because the table only
> has 254 entrys due to the addwf PCL,f at the start, therefore it
exceeeds
> the page when at 255. As my output is interrupt driven, the output
looked
> normal but wouldn't respond.
> ------------------------------------------
>                 org 0x0200
> MSB_Period
>                    addwf  PCL,f
>                    retlw  0xXX
>                    (252 other retlw 0xXX) retlw  0xXX
>                    (0x300 page)

This comes up periodically.  Now that you've been penny wise and pound
foolish, do youself a favor and spend the little extra effort to do table
lookups the right way.  The only excuse is the rather rare case where you
can't afford the few extra instructions or cycles.  This table lookup code
has no restriction as to where the code or table resides in program
memory:

;
;   Return to the caller with the table value in W for the
;   0-255 table entry number in OFFSET.  The bank must
;   already be set for access to OFFSET.
;
    movlw   high table   ;get table start address high byte
    movwf   pclath       ;init jump address high byte
    movf    offset, w    ;get the 0-255 table entry offset
    addlw   low table    ;make jump address low byte
    skip_nc              ;no carry into high byte ?
    incf    pclath       ;propagate the carry
    movwf   pcl          ;jump to the selected table entry

...

table
    retlw ...
    ...


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