----- From: "Dave VanHorn" <dvanhorn@
<Snip>
> The real question is, with a logic analyzer on all the pins, how hard would 
> it be to write the spec to rewrite your code from scratch?
</Snip>
One of our products uses 2 microcontrollers (one is dedicated)
both have "unused pins", I have the unused pins of one connected to the unused pins of the other.
One unit sends stuff to the other which ignores most of it, some of this is serial, some is simple state changes.
Makes it harder to reverse engineer when there is things going on that do not make sense.
For example the dedicated unit may only be looking for a state change on a pin, but the other controller triggers this state change by sending a random length string of random bits at a random baudrate. (ok, so it is actually pseudo-random, still confuses the competition enough that they have yet to develop a similar product)

KF4HAZ - Lonnie

> At 01:04 PM 11/28/2004, John Pearson wrote:
> 
> >How secure are the ATMega chips, the M8 and M32 specificly, when the lock 
> >bits are set (serial and parallel access)?
> 
> Anything can be cracked, but it would be pretty hard.
> Once you've set the lock bits, the only thing you can do is fully erase the 
> part.
> Unlike the Zilog, setting the lock bits does not remove your ability to 
> have the program read strings from rom.
> 
> The real question is, with a logic analyzer on all the pins, how hard would 
> it be to write the spec to rewrite your code from scratch?


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