32
8331B–AVR–03/12
Atmel AVR XMEGA AU
• Bit 6 – BOOTRST: Boot Loader Section Reset Vector
This fuse can be programmed so the reset vector is pointing to the first address in the boot
loader flash section. The device will then start executing from the boot loader flash section after
reset.
• Bit 5 – TOSCSEL: 32.768kHz Timer Oscillator Pin Selection
This fuse is used to select pin location for the 32.768kHz timer oscillator (TOSC). This fuse is
available on devices where XTAL and TOSC pins by default are shared.
Note: 1. See device datasheet for alternate TOSC position.
• Bit 4:2 – Reserved
These bits are unused and reserved for future use. For compatibility with future devices, always
write these bits to one when this register is written.
• Bit 1:0 – BODPD[1:0]: BOD Operation in Power-down Mode
These fuse bits set the BOD operation mode in all sleep modes except idle mode.
For details on the BOD and BOD operation modes, refer to ”Brownout Detection” on page 115.
4.16.4 FUSEBYTE4 – Fuse Byte4
• Bit 7:5 – Reserved
These bits are unused and reserved for future use. For compatibility with future devices, always
write these bits to one when this register is written.
Table 4-1. Boot reset fuse.
BOOTRST Reset Address
0 Reset vector = Boot loader reset
1 Reset vector = Application reset (address 0x0000)
Table 4-2. TOSCSEL fuse.
TOSCSEL Group Configuration Description
0ALTERNATE
(1)
TOSC1/2 on separate pins
1 XTAL TOSC1/2 shared with XTAL
Table 4-3. BOD operation modes in sleep modes.
BODPD[1:0] Description
00 Reserved
01 BOD enabled in sampled mode
10 BOD enabled continuously
11 BOD disabled
Bit 7 6 5 4 3 2 1 0
+0x04 – – – RSTDISBL STARTUPTIME[1:0] WDLOCK JTAGEN FUSEBYTE4
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 0
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