ATmega325PA Atmel Corporation, ATmega325PA Datasheet - Page 283

• Manufacturer Part Number: ATmega325PA
• Manufacturer: Atmel Corporation

27. Memory Programming
27.1
8285D–AVR–06/11
Program And Data Memory Lock Bits
ATmega165A/PA/325A/PA/3250A/PA/645A/P/6450A/P
The ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/6450A/6450P provides six
Lock bits which can be left unprogrammed (“1”) or can be programmed (“0”) to obtain the addi-
tional features listed in
command.
Table 27-1.
Note:
Table 27-2.
BLB12
BLB11
BLB02
BLB01
LB2
LB1
BLB0 Mode
LB Mode
Lock Bit Byte
1
2
3
1
2
3
4
1. “1” means unprogrammed, “0” means programmed
Memory Lock Bits
Lock Bit Byte
Lock Bit Protection Modes
BLB02
LB2
1
1
0
1
1
0
0
Table
BLB01
(1)
LB1
27-2. The Lock bits can only be erased to “1” with the Chip Erase
1
0
0
1
0
0
1
Bit No
7
6
5
4
3
2
1
0
Protection Type
No memory lock features enabled.
Further programming of the Flash and EEPROM is disabled in
Parallel and Serial Programming mode. The Fuse bits are
locked in both Serial and Parallel Programming mode.
Further programming and verification of the Flash and EEPROM
is disabled in Parallel and Serial Programming mode. The Boot
Lock bits and Fuse bits are locked in both Serial and Parallel
Programming mode.
No restrictions for SPM or LPM accessing the Application
section.
SPM is not allowed to write to the Application section.
SPM is not allowed to write to the Application section, and LPM
executing from the Boot Loader section is not allowed to read
from the Application section. If Interrupt Vectors are placed in
the Boot Loader section, interrupts are disabled while executing
from the Application section.
LPM executing from the Boot Loader section is not allowed to
read from the Application section. If Interrupt Vectors are placed
in the Boot Loader section, interrupts are disabled while
executing from the Application section.
(1)(2)
Description
–
–
Boot Lock bit
Boot Lock bit
Boot Lock bit
Boot Lock bit
Lock bit
Lock bit
(1)
Default Value
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
(1)
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