
150
8024A–AVR–04/08
ATmega8HVA/16HVA
27.2.1
High Byte
Note:
1. The default OSCSEL1:0 setting should not be changed. OSCSEL1:0 = ‘00’ is reserved for test
purposes. Other values are reserved for future use.
27.2.2
Low Byte
Notes:
2. The SPIEN Fuse is not accessible in SPI programming mode.
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.
27.2.3
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 27-3.
Fuse High Byte
Bit No
Fuse High Byte
Description
Default Value
7:2
–
1 (unprogrammed)
1
OSCSEL1
Oscillator Select 1
0 (programmed)
0
OSCSEL0
Oscillator Select 0
1 (unprogrammed)
Table 27-4.
Fuse Low Byte
Bit No
Fuse Low Byte
Description
Default Value
Watchdog Timer always on
1 (unprogrammed)
6
EESAVE
EEPROM memory is preserved
through the Chip Erase
1 (unprogrammed, EEPROM
not preserved)
5
Enable SPI Programming Interface
0 (programmed, SPI prog.
enabled)
4
DWEN
Enable debugWIRE
1 (unprogrammed)
3
SELFPRGEN
Self Programming enable
1 (unprogrammed)
Select start-up time
1 (unprogrammed)
Select start-up time
1 (unprogrammed)
Select start-up time
1 (unprogrammed)