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DSP56F826: how to protect the codes in flash memory?

Started by brother20010501 December 24, 2003
I am new to DSP56F826. Since it does not have the code-protection
function, can I protect the codes in the flash memory by destroying
the JTAG port electrically?



Motorola doesn't recommend to destroy the JTAG port by
high voltage because it adds unpredictable stress to
die which may cause reliability issue. Here is an
article from Motorola addressing this issue.

Charlie

--- brother20010501 <>
wrote:
> I am new to DSP56F826. Since it does not have the
> code-protection
> function, can I protect the codes in the flash
> memory by destroying
> the JTAG port electrically?


__________________________________

Attachment (not stored)
SG2093.pdf
Type: application/pdf

Charlie W-
>
> Motorola doesn't recommend to destroy the JTAG port by
> high voltage because it adds unpredictable stress to
> die which may cause reliability issue. Here is an
> article from Motorola addressing this issue.

This article does not mention JTAG. I can tell you from hard experience that
the
"co-device" method is worthless unless the JTAG port is inactive. I would cover
the
processor in epoxy and take further steps.

In places in Asia, if your product is bringing enough revenue to be copied then
it
will be.

The co-device method does have one advantage, but it's based on understanding
human
behavior, not technical: if you use a small, unmarked, non-remarkable device,
and
devise the algorithm so the processor fails (acts weird randomly) very slowly
over
time, then you have a chance to determine who is copying your product. Why?
Because
the people copying your product don't know what the little weird chip does and
if
they leave it out the copy still works fine -- maybe even for months. In that
case
you monitor customers who inquired to you, but found your price too high, and as
a
courtesy or sales follow-up offer them a free unit should they purchase anyone
elses
'compatible unit' and have trouble with it. In return for that free unit, they
have
to tell you their supplier. You'll get at least one taker, and there you go.
What
you do next, I have no comment.

Jeff Brower
system engineer
Signalogic > --- brother20010501 <>
> wrote:
> > I am new to DSP56F826. Since it does not have the
> > code-protection
> > function, can I protect the codes in the flash
> > memory by destroying
> > the JTAG port electrically?