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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? |