ATMEGA8L ATMEL [ATMEL Corporation], ATMEGA8L Datasheet - Page 219

• Manufacturer Part Number: ATMEGA8L
• Description: 8-bit AVR with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Memory
Programming
Program And Data
Memory Lock Bits
2486M–AVR–12/03
The ATmega8 provides six Lock Bits which can be left unprogrammed (“1”) or can be
programmed (“0”) to obtain the additional features listed in Table 86. The Lock Bits can
only be erased to “1” with the Chip Erase command.
Table 85. Lock Bit Byte
Note:
Table 86. Lock Bit Protection Modes
BLB12
BLB11
BLB02
BLB01
LB2
LB1
BLB0 Mode
BLB1 Mode
LB Mode
Lock Bit Byte
1
2
3
1
2
3
4
Memory Lock Bits
1. “1” means unprogrammed, “0” means programmed
BLB02
BLB12
LB2
1
1
0
1
1
0
0
BLB01
BLB11
LB1
Bit No.
1
0
0
1
0
0
1
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 Fuse Bits are locked in both Serial and Parallel
Programming modes.
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.
(2)
Description
–
–
Boot lock bit
Boot lock bit
Boot lock bit
Boot lock bit
Lock bit
Lock bit
(1)
(1)
Default Value
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
ATmega8(L)
(1)
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