Datasheet

102
ATtiny13
2535E–AVR–10/04
Memory
Programming
This section describes the different methods for Programming the ATtiny13 memories.
Program And Data
Memory Lock Bits
The ATtiny13 provides two Lock bits which can be left unprogrammed (“1”) or can be
programmed (“0”) to obtain the additional security listed in Table 43. The Lock bits can
only be erased to “1” with the Chip Erase command.
Program memory can be read out via the debugWIRE interface when the DWEN fuse is
programmed, even if the Lock Bits are set. Thus, when Lock Bit security is required,
should always debugWIRE be disabled by clearing the DWEN fuse.
Note: 1. “1” means unprogrammed, “0” means programmed
Notes: 1. Program the Fuse bits before programming the LB1 and LB2.
2. “1” means unprogrammed, “0” means programmed
Table 42. Lock Bit Byte
(1)
Lock Bit Byte Bit No Description Default Value
7 – 1 (unprogrammed)
6 – 1 (unprogrammed)
5 – 1 (unprogrammed)
4 – 1 (unprogrammed)
3 – 1 (unprogrammed)
2 – 1 (unprogrammed)
LB2 1 Lock bit 1 (unprogrammed)
LB1 0 Lock bit 1 (unprogrammed)
Table 43. Lock Bit Protection Modes
(1)(2)
Memory Lock Bits Protection Type
LB Mode LB2 LB1
1 1 1 No memory lock features enabled.
210
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.
(1)
debugWire is disabled.
300
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)
debugWire
is disabled.