On Mon, 22 Nov 1999, Mark Willis wrote:

> In my case, the particular client of mine, wants to be sure no purchaser
> of their product has an easy time reverse-engineering their processing
> code;  They've been 3+ years figuring out how to do this, and they would
> like less competition, instead of more.  Just writing something to EPRom
> isn't going to destroy the program code.  (Code protect:ALL should do
> them, I think, but we'll discuss it.)

  I've had success by "blowing" the data pin out on PICs.  Example: a
12C508.  Ground every pin but pin 7, then put 10VDC on pin 7 for a second.
Bond wire fried.  You lose the use of pin 7 forever, but as it is the data
I/O pin for programming, considerably hampers reading the rom save for
those who can desurface the chip package and probe the die.

  Not strictly recommended for commercial apps, but I've never lost a PIC
to this procedure yet.

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