>Kim Cooper of Microchip wrote:
>> Sorry, ocde protect on the newer devices, the PIC16C622 included, is
>> permanent.
>
>This is really disastrous, as sometimes the code protect bit is set
>erroneously by the programmer.  I've seen this happen on both the PICSTART
>and the Parallax programmers.  Maybe it's really a design defect in the
>device?  Anyhow, two out of five of my windowed '622 parts are now only
>suitable to be used as jewelry.
>
They could put in annother unerasable bit which, when programmed, inhibits
writing to the code-protect bit (forces it to write 1 no matter what the
programmer loads to the config register).  This bit would be programmed at
the factory on ceramic devices, making it impossible to code-protect them.
The inhibit bit would be left blank on the plastic ones, allowing the code
protect to be set after programming by the customer (after the protect bit
is programmed, the state of the inhibit bit is not relevant).  Then there
would be no way to kill a ceramic PIC by protecting it by accident, and the
same die could be used in either version.

-Mike