Memory programming, 1 program and data memory lock bits, Memory program – Rainbow Electronics ATmega64M1 User Manual
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8209A–AVR–08/09
ATmega16M1/32M1/64M1
28. Memory Programming
28.1
Program And Data Memory Lock Bits
The ATmega16M1/32M1/64M1 provides six Lock bits which can be left unprogrammed (“1”) or
can be programmed (“0”) to obtain the additional features listed in
. The Lock bits can
only be erased to “1” with the Chip Erase command.
Note:
1. “1” means unprogrammed, “0” means programmed.
Notes:
1. Program the Fuse bits and Boot Lock bits before programming the LB1 and LB2.
2. “1” means unprogrammed, “0” means programmed
Table 28-1.
Lock Bit Byte
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)
Table 28-2.
Lock Bit Protection Modes
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.
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.