Fuse bits, Atmega128(l) – Rainbow Electronics ATmega128L User Manual
Page 280
280
ATmega128(L)
2467B–09/01
Notes:
1. Program the fuse bits before programming the Lock bits.
2. “1” means unprogrammed, “0´means programmed
Fuse Bits
The ATmega128 has three fuse bytes.
Table 118 - Table 120 describe briefly the func-
tionality of all the fuses and how they are mapped into the fuse bytes. Note that the
fuses are read as logical zero, “0”, if they are programmed.
Notes:
1. See
“ATmega103 and ATmega128 Compatibility” on page 4 for details.
2. See
“Watchdog Timer Control Register – WDTCR” on page 51 for details.
BLB1 mode
BLB12
BLB11
1
1
1
No restrictions for SPM or (E)LPM accessing the Boot
Loader section.
2
1
0
SPM is not allowed to write to the Boot Loader section.
3
0
0
SPM is not allowed to write to the Boot Loader section,
and (E)LPM executing from the Application section is not
allowed to read from the Boot Loader section. If interrupt
vectors are placed in the Application section, interrupts
are disabled while executing from the Boot Loader
section.
4
0
1
(E)LPM executing from the Application section is not
allowed to read from the Boot Loader section. If interrupt
vectors are placed in the Application section, interrupts
are disabled while executing from the Boot Loader
section.
Table 117. Lock Bit Protection Modes
(Continued)
Memory Lock Bits
Protection Type
Table 118. Extended Fuse Byte
Extended Fuse Byte
Bit No.
Description
Default Value
–
7
–
1
–
6
–
1
–
5
–
1
–
4
–
1
–
3
–
1
–
2
–
1
M103C
1
ATmega103 compatibility mode
0 (programmed)
WDTON
0
Watchdog timer always on
1 (unprogrammed)