Datasheet
ATmega164A/PA/324A/PA/644A/PA/1284/P
2018 Microchip Technology Inc. Data Sheet Complete DS40002070A-page 297
Note: 1. The SPIEN Fuse is not accessible in serial programming mode.
2. The default value of BOOTSZ1..0 results in maximum Boot Size. See Table 26-10 on page 290 for details.
3. See ”WDTCSR – Watchdog Timer Control Register” on page 67 for details.
4. Never ship a product with the OCDEN Fuse programmed regardless of the setting of Lock bits and JTAGEN
Fuse. A programmed OCDEN Fuse enables some parts of the clock system to be running in all sleep modes.
This may increase the power consumption.
Note: 1. The default value of SUT1..0 results in maximum start-up time for the default clock source. See ”” on page 333
for details.
2. The default setting of CKSEL3..0 results in internal RC Oscillator @ 8MHz. See Table 9-1 on page 39 for
details.
3. The CKOUT Fuse allow the system clock to be output on PORTB1. See ”Clock Output Buffer” on page 47 for
details.
4. See ”System Clock Prescaler” on page 47 for details.
The status of the Fuse bits is not affected by Chip Erase. Note that the Fuse bits are locked if Lock bit1 (LB1) is
programmed. Program the Fuse bits before programming the Lock bits.
Table 27-4. Fuse High byte
Fuse High byte Bit no. Description Default value
OCDEN
(4)
7 Enable OCD
1 (unprogrammed, OCD
disabled)
JTAGEN 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)
BOOTSZ1 2
Select Boot Size (see Table 27-9 on
page 300 for details)
0 (programmed)
(2)
BOOTSZ0 1
Select Boot Size (see Table 27-9 on
page 300 for details)
0 (programmed)
(2)
BOOTRST 0 Select Reset Vector 1 (unprogrammed)
Table 27-5. Fuse Low byte
Fuse Low byte Bit no. Description Default value
CKDIV8
(4)
7 Divide clock by 8 0 (programmed)
CKOUT
(3)
6 Clock output 1 (unprogrammed)
SUT1 5 Select start-up time 1 (unprogrammed)
(1)
SUT0 4 Select start-up time 0 (programmed)
(1)
CKSEL3 3 Select Clock source 0 (programmed)
(2)
CKSEL2 2 Select Clock source 0 (programmed)
(2)
CKSEL1 1 Select Clock source 1 (unprogrammed)
(2)
CKSEL0 0 Select Clock source 0 (programmed)
(2)