Datasheet

282
2545F–AVR–06/05
ATmega48/88/168
Note: 1. The default value of BOOTSZ1..0 results in maximum Boot Size. See Table 26-10 on page
285 for details.
Notes: 1. See ”Alternate Functions of Port C” on page 80 for description of RSTDISBL Fuse.
2. The SPIEN Fuse is not accessible in serial programming mode.
3. See ”Watchdog Timer Control Register - WDTCSR” on page 52 for details.
4. See Table 9-2 on page 46 for BODLEVEL Fuse decoding.
Table 26-5. Extended Fuse Byte for mega88/168
Extended Fuse Byte Bit No Description Default Value
–7– 1
–6– 1
–5– 1
–4– 1
–3– 1
BOOTSZ1 2
Select Boot Size
(see Table 113 for details)
0 (programmed)
(1)
BOOTSZ0 1
Select Boot Size
(see Table 113 for details)
0 (programmed)
(1)
BOOTRST 0 Select Reset Vector 1 (unprogrammed)
Table 26-6. Fuse High Byte
High Fuse Byte Bit No Description Default Value
RSTDISBL
(1)
7 External Reset Disable 1 (unprogrammed)
DWEN 6 debugWIRE Enable 1 (unprogrammed)
SPIEN
(2)
5
Enable Serial Program and
Data Downloading
0 (programmed, SPI
programming enabled)
WDTON
(3)
4 Watchdog Timer Always On 1 (unprogrammed)
EESAVE 3
EEPROM memory is
preserved through the Chip
Erase
1 (unprogrammed), EEPROM
not reserved
BODLEVEL2
(4)
2
Brown-out Detector trigger
level
1 (unprogrammed)
BODLEVEL1
(4)
1
Brown-out Detector trigger
level
1 (unprogrammed)
BODLEVEL0
(4)
0
Brown-out Detector trigger
level
1 (unprogrammed)