ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 163

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

21. Memory Programming
21.1
7701E–AVR–02/11
Program And Data Memory Lock Bits
This section describes the different methods for programming the Atmel
memories.
The ATtiny24/44/84 provides two lock bits which can be left unprogrammed (set to one) or can
be programmed (set to zero) to obtain the additional security listed in
The lock bits can only be erased to one with the chip erase command.
Program memory can be read via the debugWIRE interface when the DWEN fuse is pro-
grammed even if the lock bits are set. Thus, when lock bit security is required, debugWIRE
should always be disabled by clearing the DWEN fuse.
Table 21-1.
Note:
Table 21-2.
Notes:
LB2
LB1
LB Mode
Lock Bit Byte
1
2
3
1. “1” means unprogrammed, “0” means programmed
1. Program the Fuse bits before programming LB1 and LB2.
2. “1” means unprogrammed, “0” means programmed
Memory Lock Bits
Lock Bit Byte
Lock Bit Protection Modes
LB2
1
1
0
Atmel ATtiny24/44/84 [Preliminary]
(1)
LB1
1
0
0
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
High-voltage and Serial Programming mode. The Fuse bits are
locked in both Serial and High-voltage Programming mode.
debugWire is disabled.
Further programming and verification of the Flash and
EEPROM is disabled in High-voltage and Serial Programming
mode. The Fuse bits are locked in both Serial and High-voltage
Programming mode.
(1)(2)
Description
–
–
–
–
–
–
Lock bit
Lock bit
(1)
debugWire is disabled.
Default Value
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
Table 21-2 on page
®
ATtiny24/44/84
163.
(1)
163