Datasheet

248
7734Q–AVR–02/12
AT90PWM81/161
21. Memory Programming
21.1 Program And Data Memory Lock Bits
The AT90PWM81/161 provides six Lock bits which can be left unprogrammed (“1”) or can be
programmed (“0”) to obtain the additional features listed in Table 21-2. The Lock bits can only be
erased to “1” with the Chip Erase command.
Notes: 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 21-1. 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)
Table 21-2. Lock bit protection modes
(1)(2)
.
Memory lock bits Protection type
LB mode LB2 LB1
1 1 1 No memory lock features enabled
21 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)
30 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)