Datasheet

291
2490R–AVR–02/2013
ATmega64(L)
Notes: 1. Program the Fuse bits before programming the Lock bits.
2. “1” means unprogrammed, “0” means programmed
Fuse Bits The ATmega64 has three fuse bytes. Table 117 - Table 119 describe briefly the functionality of
all the fuses and how they are mapped into the fuse bytes. Note that the fuses are read as logi-
cal zero, “0”, if they are programmed.
Notes: 1. See “ATmega103 and ATmega64 Compatibility” on page 4 for details.
2. See “WDTCR – Watchdog Timer Control Register” on page 57 for details.
1 1 1 No restrictions for SPM or LPM accessing the Boot Loader
section.
2 1 0 SPM is not allowed to write to the Boot Loader section.
3 0 0 SPM is not allowed to write to the Boot Loader section,
and LPM executing from the Application section is not
allowed to read from the Boot Loader section. If Interrupt
Vectors are placed in the Application section, interrupts
are disabled while executing from the Boot Loader section.
4 0 1 LPM executing from the Application section is not allowed
to read from the Boot Loader section. If Interrupt Vectors
are placed in the Application section, interrupts are
disabled while executing from the Boot Loader section.
Table 116. Lock Bit Protection Modes
(2)
(Continued)
Memory Lock Bits Protection Type
Table 117. Extended Fuse Byte
Fuse Ext Byte Bit no Description Default Value
–7– 1
–6– 1
–5– 1
–4– 1
–3– 1
–2– 1
M103C
(1)
1 ATmega103 compatibility mode 0 (programmed)
WDTON
(2)
0 Watchdog Timer always on 1 (unprogrammed)