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Chapter 10
Code Protection and Security
Preliminary User’s Manual U17566EE1V2UM00
Note
1.
After you have set protection levels 1 or 2, set the “block erase disable flag”
in the flash extra area. Otherwise, an unauthorized person could erase the
block that contains the ID code or the “N-Wire use enable flag”,
respectively, and thus suspend the protection.
2.
If an unauthorized user tries to find out the 10-byte ID by comparing all
possible ID codes, this will take up to 3.83 x 10
8
years at 100 MHz.
For more details refer to
“Security function“ on page 879
.
Table 10-1
Possible results of ID code comparison
N-Wire use enable flag
ID code
Protection Level
0
X
a
a)
Codes are not compared
Level 2: Full protection
N-Wire debug interface cannot be used.
b
b)
Once the N-Wire debug interface has been set as “use-prohibited”, it cannot be
used until the flash memory is re-programmed.
1
user-specific
ID code
Level 1: ID code protection
N-Wire debug interface can only be used
if the user enters the correct ID code.
ID code is all
ones
c
c)
This is the default state after the flash memory has been erased.
Level 0: No protection
N-Wire debug interface can be used.
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