Datasheet
287
2545T–AVR–05/11
ATmega48/88/168
Note: 1. The default value of BOOTSZ1..0 results in maximum boot size. See Table 28-11 on page 290
for details.
Notes: 1. See “Alternate functions of port C” on page 81 for description of RSTDISBL fuse.
2. The SPIEN fuse is not accessible in serial programming mode.
3. See “WDTCSR – Watchdog timer control register” on page 53 for details.
4. See Table 29-4 on page 307 for BODLEVEL fuse decoding.
Table 28-5. 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 27-6 on page 281
and Table 27-9 on page 282
for details)
0 (programmed)
(1)
BOOTSZ0 1
Select boot size
(see Table 27-6 on page 281
and Table 27-9 on page 282
for details)
0 (programmed)
(1)
BOOTRST 0 Select reset vector 1 (unprogrammed)
Table 28-6. 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)