Datasheet

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: 1. See Table 9-1 on page 25 for details about start-up time.
2. The SPIEN Fuse is not accessible in SPI programming mode.
3. See ”WDTCSR – Watchdog Timer Control Register” on page 49 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.
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
7WDTON
(3)
Watchdog Timer always on 1 (unprogrammed)
6 EESAVE
EEPROM memory is preserved
through the Chip Erase
1 (unprogrammed, EEPROM
not preserved)
5 SPIEN
(2)
Enable SPI Programming Interface
0 (programmed, SPI prog.
enabled)
4 DWEN Enable debugWIRE 1 (unprogrammed)
3 SELFPRGEN Self Programming enable 1 (unprogrammed)
2SUT2
(1)
Select start-up time 1 (unprogrammed)
1SUT1
(1)
Select start-up time 1 (unprogrammed)
0SUT0
(1)
Select start-up time 1 (unprogrammed)