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30
8210C–AVR–09/11
Atmel AVR XMEGA D
• Bit 3 – EESAVE: EEPROM is Preserved through the Chip Erase
A chip erase command will normally erase the flash, EEPROM and internal SRAM. If this fuse is
programmed, the EEPROM is not erased during chip erase. This is useful if EEPROM is used to
store data independent of software revision.
Changes to the EESAVE fuse bit take effect immediately after the write timeout elapses. Hence,
it is possible to update EESAVE and perform a chip erase according to the new setting of
EESAVE without leaving and reentering programming mode.
• Bit 2:0 – BODLEVEL[2:0]: Brownout Detection Voltage Level
These fuse bits sets the BOD voltage level. Refer to
for details. For
BOD level nominal values, see
.
4.13.5
LOCKBITS – Lock Bit register
• Bit 7:6 – BLBB[1:0]: Boot Lock Bit Boot Loader Section
These lock bits control the security level for the boot loader section. The BLBB bits can only be
written to a more strict locking. Resetting the BLBB bits is possible by executing a chip erase
command.
Table 4-7.
EEPROM preserved through chip erase
EESAVE
Description
0
EEPROM is preserved during chip erase
1
EEPROM is erased during chip erase
Bit
7
6
5
4
3
2
1
0
+0x07
BLBB[1:0]
BLBA[1:0]
BLBAT[1:0]
LB[1:0]
LOCKBITS
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial Value
1
1
1
1
1
1
1
1