:-) if you grind the chip information off of the top of the I.C.'s you
will creat a HUGE headache for the design copier. Low tech way of slowing
them down.

On Sat, 27 Jun 1998, Mark Willis wrote:

> Michael S. Hagberg wrote:
> >
> > >Hello again fellow PIClisters,
> > >
> > >Can someone tell me if it's possible to read a PIC that has had it's
> > >protection fuse blown?
> >
> > YES
> >
> > >I've heard there's a way to apply a voltage and put it into test mode.
> >
> > Not exactly, but I will not tell how it's done.
> >
> > > If I create a programmed chip and protect it, can someone else come along
> > and copy it?
> >
> > YES (see number 1)
> >
> > Are there any ways to prevent this from happening?
> >
> > The best (not full proof) way is to zap the program pin with enough voltage
> > and current to destroy it without blowing up the chip.
> >
> > sorry the news isn't better, but not being able to protect the code is no
> > reason for not developing a good product and putting it on the market. i am
> > much more concerned about someone copying my idea than stealing my code.
> >
> > michael
>
>   On one circuit I have been working on, the capability to do the job
> (controlling HV DC to accomplish this job) in a array of PICs instead of
> with a relatively expensive & perishable array of PCs, IS the idea (i.e.
> it's easy to do with an expensive array of Pentii, almost impossible to
> do with a flock of cheap PICs, but quite cost-effective once you figure
> the tricks out.)  In that (admittedly rareish) sort of situation, having
> the code stolen means the idea's stolen.  Tough to protect a PIC, in any
> better way than you mention, without resorting to pyrotechnic devices &
> etc.  (i.e. if you open the case an M-80 blows the chip apart) - Thought
> of a good way for this industrial device, though;  Have a fairly
> powerful spring which is released to smash the chip if someone breaks
> into the control box.  (Rigged like an old caplock musket or like a
> modern rifle striker.)  Easy to do that...  Putting 220VDC across
> Vdd/Vss would do it, too.  Expect to replace the parts on your next
> service call. <G>
>
>   Mark Willis, mwillis@nwlink.com
>