Rainbow Electronics ATmega128L - Manual (Page 281)

281
ATmega128(L)
2467B–09/01
Notes: 1. The SPIEN fuse is not accessible in serial programming mode.
2. The CKOPT fuse functionality depends on the setting of the CKSEL bits. See
“Clock
Sources” on page 34
for details.
3. The default value of BOOTSZ1..0 results in maximum Boot Size. See Table 113 on
page 277
Notes: 1. The default value of SUT1..0 results in maximum start-up time. See Table 14 on page
38 for details.
2. The default setting of CKSEL3..0 results in internal RC oscillator @ 1 MHz. See
Table 6 on page 34 for details.
The status of the Fuse bits is not affected by Chip Erase. Note that the Fuse bits are
locked if lock bit1 (LB1) is programmed. Program the Fuse bits before programming the
Lock bits.
Latching of Fuses The fuse values are latched when the device enters programming mode and changes of
the fuse values will have no effect until the part leaves programming mode. This does
not apply to the EESAVE fuse which will take effect once it is programmed. The fuses
are also latched on power-up in normal mode.
Table 119. Fuse High Byte
Fuse High
Byte
Bit No. Description Default Value
OCDEN 7 Enable OCD 1 (unprogrammed, OCD
disabled)
JTAGEN 6 Enable JTAG 0 (programmed, JTAG enabled)
SPIEN (1) 5 Enable Serial Program and
Data Downloading
0 (programmed, SPI prog.
enabled)
CKOPT (2) 4 Oscillator options 1 (unprogrammed)
EESAVE 3 EEPROM memory is preserved
through the Chip Erase 1 (unprogrammed, EEPROM not
preserved)
BOOTSZ1 2 Select Boot Size (see
Table 113
for details)
0 (programmed) (3)
BOOTSZ0 1 Select Boot Size (see
Table 113
for details)
0 (programmed) (3)
BOOTRST 0 Select reset vector 1 (unprogrammed)
Table 120. Fuse Low Byte
Fuse Low
Byte
Bit No. Description Default Value
BODLEVEL 7 Brown out detector trigger level 1 (unprogrammed)
BODEN 6 Brown out detector enable 1 (unprogrammed, BOD disabled)
SUT1 5 Select start-up time 1 (unprogrammed) (1)
SUT0 4 Select start-up time 0 (programmed) (1)
CKSEL3 3 Select Clock source 0 (programmed) (2)
CKSEL2 2 Select Clock source 0 (programmed) (2)
CKSEL1 1 Select Clock source 0 (programmed) (2)
CKSEL0 0 Select Clock source 1 (unprogrammed) (2)