For a long time, I have wondered how solid Microchip's code protection =
feature is. Especially for their new Flash based program memory PICs. =
From what I understand, it
is much more difficult to reverse engineer Flash Memory, compared to =
EPROM, since with EPROM memory, you can remove the chip's casing and use =
an electron microscope to read the state of the internal EPROM. Plus, I =
hear that now they are hiding the code-protect fuse inside the program =
memory array. While this may start a debate
on how easy or not easy it may be to reverse engineer someone's PIC =
code, by monitoring I/Os. In my opinion, a complex firmware design can =
make this quite difficult. Especially as these PICs become more =
sophisiticated with more I/Os, more internal peripherals, larger program =
memories and more elaborate instruction sets. One trick I frequently =
use, is to send out random states on I/O's that won't affect circuit =
operation. However, I have heard of companies that specialize in reverse =
engineering PICs and other microcontrollers, creating an ASM file from =
extracted data. How much do these companies charge? The bottom line, how =
secure are these PICs?

Neil

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