180
ATmega8515(L)
2512K–AVR–01/10
Notes:
1. Program the Fuse bits before programming the Lock bits.
2. “1” means unprogrammed, “0” means programmed
Fuse bits
The ATmega8515 has two Fuse bytes.
Table 83 and
Table 84 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:
2. The SPIEN Fuse is not accessible in serial programming mode.
3. The CKOPT Fuse functionality depends on the setting of the CKSEL bits.
See “Clock4. The default value of BOOTSZ1..0 results in maximum Boot Size. See
Table 78 on11
1
No restrictions for SPM or LPM accessing the Boot Loader
section.
2
1
0
SPM is not allowed to write to the Boot Loader section.
30
0
SPM is not allowed to write to the Boot Loader section,
and 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.
40
1
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 82. Lock Bit Protection Modes
(2) (Continued)
Memory Lock bits
Protection Type
Table 83. Fuse High Byte
Fuse High Byte
Bit no
Description
Default Value
S8515C
7
AT90S4414/8515 compatibility
mode
1 (unprogrammed)
WDTON
6
Watchdog Timer always on
1 (unprogrammed)
5
Enable Serial Program and Data
Downloading
0 (programmed, SPI prog.
enabled)
4
Oscillator options
1 (unprogrammed)
EESAVE
3
EEPROM memory is preserved
through the Chip Erase
1 (unprogrammed,
EEPROM not preserved)
BOOTSZ1
2
details)
BOOTSZ0
1
details)
BOOTRST
0
Select Reset Vector
1 (unprogrammed)