337
7679H–CAN–08/08
AT90CAN32/64/128
Notes: 1. Program the Fuse bits and Boot Lock bits before programming the LB1 and LB2.
2. “1” means unprogrammed, “0” means programmed
25.2 Fuse Bits
The AT90CAN32/64/128 has three Fuse bytes. Table 25-3, Table 25-4 and Table 25-5 describe
briefly the functionality of all the fuses and how they are mapped into the Fuse bytes. Note that
the fuses are read as logical zero, “0”, if they are programmed.
Note: 1. See Table 7-2 on page 54 for BODLEVEL Fuse decoding.
2 1 0 SPM is not allowed to write to the Boot Loader section.
300
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.
401
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 25-2. Lock Bit Protection Modes
(1)(2)
(Continued)
Memory Lock Bits Protection Type
Table 25-3. Extended Fuse Byte
Fuse Extended Byte Bit No Description Default Value
–7– 1
–6– 1
–5– 1
–4– 1
BODLEVEL2
(1)
3 Brown-out Detector trigger level 1 (unprogrammed)
BODLEVEL1
(1)
2 Brown-out Detector trigger level 1 (unprogrammed)
BODLEVEL0
(1)
1 Brown-out Detector trigger level 1 (unprogrammed)
TA0SEL 0 (Reserved for factory tests) 1 (unprogrammed)
Table 25-4. Fuse High Byte
Fuse High Byte Bit No Description Default Value
OCDEN
(4)
7 Enable OCD 1 (unprogrammed, OCD disabled)
JTAGEN
(5)
6 Enable JTAG 0 (programmed, JTAG enabled)
SPIEN
(1)
5
Enable Serial Program and
Data Downloading
0 (programmed, SPI prog. enabled)
WDTON
(3)
4 Watchdog Timer always on 1 (unprogrammed)
EESAVE 3
EEPROM memory is preserved
through the Chip Erase
1 (unprogrammed, EEPROM not preserved)
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