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XMEGA A [MANUAL]
8077I–AVR–11/2012
Bit 3:2 – BLBAT[1:0]: Boot Lock Bit Application Table Section
These lock bits control the software security level for accessing the application table section for software access. The
BLBAT bits can only be written to a more strict locking. Resetting the BLBAT bits is possible only by executing a chip
erase command
Table 4-10. Boot lock bit for the application table section.
Bit 1:0 – LB[1:0]: Lock Bits(1)
These lock bits control the security level for the flash and EEPROM during external programming. These bits are writable
only through an external programming interface. Resetting the lock bits is possible only by executing a chip erase
command. All other access; using the TIF and OCD, is blocked if any of the Lock Bits are written to 0. These bits do not
block any software access to the memory
Table 4-11.
Lock bit protection mode.
Note:
1.
Program the Fuse Bits and Boot Lock Bits before programming the Lock Bits.
BLBAT[1:0]
Group Configuration
Description
11
NOLOCK
No lock – no restrictions for SPM and (E)LPM accessing the application
table section.
10
WLOCK
Write lock – SPM is not allowed to write the application table
01
RLOCK
Read lock – (E)LPM executing from the boot loader section is not allowed to
read from the application table section.
If the interrupt vectors are placed in the boot loader section, interrupts are
disabled while executing from the application section.
00
RWLOCK
Read and write lock – SPM is not allowed to write to the application table
section, and (E)LPM executing from the boot loader section is not allowed to
read from the application table section.
If the interrupt vectors are placed in the boot loader section, interrupts are
disabled while executing from the application section.
LB[1:0]
Group Configuration
Description
11
NOLOCK3
No lock – no memory locks enabled.
10
WLOCK
Write lock – programming of the flash and EEPROM is disabled for the
programming interface. Fuse bits are locked for write from the programming
interface.
00
RWLOCK
Read and write lock – programming and read/verification of the flash and
EEPROM are disabled for the programming interface. The lock bits and
fuses are locked for read and write from the programming interface.