Hi Humberto,

You wrote a pretty good summary of how the PC works in the PICMicro and
finally asked:

>Thus for all the chips with a program boundary under 2K (as 16F84 is), why
to care for those stupid bits in PCLATH ? In Jim's case, if I have to
perform a call or goto inside the int service routine, simply I can do it
without the need of handling the bits in PCLATH and saving it for future
restore. The call or goto instruction always jumps to the correct address
and returning to the original address is guaranteed as well. I knew that
care has to be taken only when performing computed goto in table read for
page crossing handling.
>
>    Am I missing something relevant with this issue ?

PCLATH is an issue in the '84 and other devices with 2K or less if you have
a table that is not in the first 256 addresses of Control Store or is so
long that the table extends past the first 256 addresses.

If you're starting to learn how the PIC works, I highly recommend keeping
all tables in the first 256 addresses and not changing PCLATH at all.

Good Luck!

myke

"I was well aware that the processes of puberty are often fatal to psychic
power."
- Sir Arthur Conan Doyle