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XMEGA A [MANUAL]
8077I–AVR–11/2012
4.16.6 LOCKBITS – Lock Bit register
Bit 7:6 – BLBB[1:0]: Boot Lock Bit Boot Loader Section
These lock bits control the software security level for accessing the boot loader section. The BLBB bits can only be
written to a more strict locking. Resetting the BLBB bits is possible only by executing a chip erase command.
Table 4-8.
Boot lock bit for the boot loader section.
Bit 5:4 – BLBA[1:0]: Boot Lock Bit Application Section
These lock bits control the software security level for accessing the application section. The BLBA bits can only be
written to a more strict locking. Resetting the BLBA bits is possible only by executing a chip erase command.
Table 4-9.
Boot lock bit for the application section.
Bit
7654
3210
+0x07
BLBB[1:0]
BLBA[1:0]
BLBAT[1:0]
LB[1:0]
Read/Write
R/W
Initial Value
1111
BLBB[1:0]
Group Configuration
Description
11
NOLOCK
No lock – no restrictions for SPM and (E)LPM accessing the boot loader
section.
10
WLOCK
Write lock – SPM is not allowed to write the boot loader section.
01
RLOCK
Read lock – (E)LPM executing from the application section is not allowed to
read from the boot loader section.
If the interrupt vectors are placed in the application section, interrupts are
disabled while executing from the boot loader section.
00
RWLOCK
Read and write lock – SPM is not allowed to write to the boot loader section,
and (E)LPM executing from the application section is not allowed to read
from the boot loader section.
If the interrupt vectors are placed in the application section, interrupts are
disabled while executing from the boot loader section.
BLBA[1:0]
Group Configuration
Description
11
NOLOCK
No Lock - no restrictions for SPM and (E)LPM accessing the application
section.
10
WLOCK
Write lock – SPM is not allowed to write the application section.
01
RLOCK
Read lock – (E)LPM executing from the boot loader section is not allowed to
read from the application 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 section,
and (E)LPM executing from the boot loader section is not allowed to read
from the application section.
If the interrupt vectors are placed in the boot loader section, interrupts are
disabled while executing from the application section.