Martin Kirk <mlk@asu.edu> wrote:
>Hi,
>
>Will someone please give me a brief list of the requirements for clearing
>the registers when moving one's code to non-windowed pics?  I assume it
>is a simple clear all registers operation.  Please confirm.
>

AFAIK, the non-window PICs have *exactly* the same chip in them as the
window ones.  So there should be no difference in operation between one type
and the other, other than inability to erase the non-window one.

(In an earlier thread, someone noted that newer versions of the window chips
have a non-erasable code protect bit.  So if this bit is set, a windowed
chip would be non-reusable as well.  Has Microchip issued an exact statement
on this?)

If you're counting on light through the window setting the RAM (registers?)
in a certain condition, this is very bad practice, not certain to work in
any case.  It is important to design your code so it doesn't assume anything
about the state of the RAM on power-up.  The special function registers are
reset as described in the table in the data book, but the RAM is not
guaranteed to be reset to any particular state, window chip or not.

There is no single "clear all registers" instruction.  However the FAQ
contains a good example of a loop which will do it.  Depending on the number
of locations that must be cleared for your code, it may be simpler to just
use a few clrf's on the vital locations.

-Mike