Datasheet

28. MEMPROG- Memory Programming
28.1. Program And Data Memory Lock Bits
The devices provides six Lock bits. These can be left unprogrammed ('1') or can be programmed ('0') to
obtain the additional features listed in Table. Lock Bit Protection Modes in this section. The Lock bits can
only be erased to “1” with the Chip Erase command.
Table 28-1. Lock Bit Byte
(1)
Lock Bit Byte Bit No. Description Default Value
7 – 1 (unprogrammed)
6 – 1 (unprogrammed)
BLB12 5 Boot Lock bit 1 (unprogrammed)
BLB11 4 Boot Lock bit 1 (unprogrammed)
BLB02 3 Boot Lock bit 1 (unprogrammed)
BLB01 2 Boot Lock bit 1 (unprogrammed)
LB2 1 Lock bit 1 (unprogrammed)
LB1 0 Lock bit 1 (unprogrammed)
Note:
1. '1' means unprogrammed, '0' means programmed.
Table 28-2. Lock Bit Protection Modes
(1)(2)
Memory Lock Bits Protection Type
LB Mode LB2 LB1
1 1 1 No memory lock features enabled.
2 1 0 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.
(1)
3 0 0 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.
(1)
Note:
1. Program the Fuse bits and Boot Lock bits before programming the LB1 and LB2.
2. '1' means unprogrammed, '0' means programmed.
Atmel ATmega16M1/32M1/64M1 [DATASHEET]
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