104
8126F–AVR–05/12
ATtiny13A
17.2
Fuse Bytes
The ATtiny13A has two fuse bytes.
and
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.
Notes:
1. Enables SPM instruction. See
“Self-Programming the Flash” on page 98
.
2. DWEN must be unprogrammed when lock Bit security is required.
Memory Lock Bits” on page 103.
3. See
for BODLEVEL fuse decoding.
4. See
“Alternate Functions of Port B” on page 55
for description of RSTDISBL and DWEN fuses.
When programming the RSTDISBL fuse, High-voltage Serial programming has to be used to
change fuses to perform further programming.
Notes:
1. The SPIEN fuse is not accessible in SPI Programming mode.
2. Programming this fues will disable the Watchdog Timer Interrupt. See
for details.
3. See
“System Clock Prescaler” on page 26
for details.
4. The default value of SUT[1:0] results in maximum start-up time for the default clock source.
See
for details.
5. The default setting of CKSEL[1:0] results in internal RC Oscillator @ 9.6 MHz. See
for details.
Table 17-3.
Fuse High Byte
Fuse Bit
Bit No
Description
Default Value
–
7
–
1 (unprogrammed)
–
6
–
1 (unprogrammed)
–
5
–
1 (unprogrammed)
4
Self Programming Enable
1 (unprogrammed)
DWEN
3
debugWire Enable
1 (unprogrammed)
2
Brown-out Detector trigger level
1 (unprogrammed)
1
Brown-out Detector trigger level
1 (unprogrammed)
0
External Reset disable
1 (unprogrammed)
Table 17-4.
Fuse Low Byte
Fuse Bit
Bit No
Description
Default Value
SPIEN
7
Enable Serial Programming and Data
Downloading
0 (programmed)
(SPI prog. enabled)
EESAVE
6
Preserve EEPROM memory through
Chip Erase
1 (unprogrammed)
(memory not preserved)
WDTON
5
Watchdog Timer always on
1 (unprogrammed)
4
Divide clock by 8
0 (programmed)
3
Select start-up time
1 (unprogrammed)
2
Select start-up time
0 (programmed)
1
Select Clock source
1 (unprogrammed)
0
Select Clock source
0 (programmed)