> > What's the trick to doing a lookup table in ROM with a 16C73?
>
> Table:
>         retlw   'A'
>         retlw   'b'
>         retlw   'c'
>         ...
> Lookup:
>
> > The only thing I can find is inderect into the Data memory using the FSR
> > and the INDF registers.

Hello Peter L. Peres. You forgot to mention about main mechanism for
tablelookup:

Lookup:
                        ;PCLATH must point to the same program page
                        ;where Table data are located
                        ;for this example table must not accross
                        ;the border of current program page
        addwf   pcl,f

        DT      "Hello words",0xD,0xA,0

Resulting from what value W register contain before call this Lookup
subroutine
it will be returning different values. For instance if W is changed from
0 upto 13d
values you will receive the phrase "Hello world" with CR/LF and finally
null/stop
symbol. After you program receive null it have to stop reading this
message. It is
not only way to set a message length but it practically suitable for
driving
ascii arrays. For another types of data you may apply another variant of
definition
of demanding quantity of data. For instance every field of data can
contain in its
header information about itself structure and size.


Hello Richard A. Smith. Some words specially for you.

The are few things you must take a care about:

0. Have a PIC16/17 DataBook/CD on your hands. This always helpful to
solve RTFM
   situation without asking non-serious questions
1. Strongly control the W value before proceeding the addwf pcl,f
operation.
   Othewise you can simply fly out of data field and it result to
instead of
   having demanding value in W and returning to normal program
functioning
   you will get abnormal mode of program operation when you code
sometimes
   will doing something strange.
2. Strongly control the PCLATH register due to this reason too.
   This is truely also for GOTO/CALL commands in 4K/8K of program memory
PIC's
3. Carefully check saving/restoring interrupt service code. For common
situations
   you should save/restore the following resources: W,STATUS,PCLATH,FSR

Probably I forget something but mainly this notes will help you in
reading
the PIC16/17 databook :) I hope you will get enjoy from PIC programming.
:)))

WBR Dmitry.