Datasheet

Figure 9-2. Crystal oscillator connections
XTAL2
XTAL1
GND
C2
C1
The oscillator can operate in three different modes, each optimized for a specific frequency range. The
operating mode is selected by the fuses CKSEL3..1 as shown in the table below.
Table 9-3. Crystal oscillator operating modes
CKSEL3..1 Frequency range [MHz] Recommended range for
capacitors C1 and C2 for use
with crystals [pF]
100
(1)
0.4 - 0.9 -
101 0.9 - 3.0 12 - 22
110 3.0 - 8.0 12 - 22
111 8.0 -16.0 12 - 22
Note: This option should not be used with crystals, only with ceramic resonators.
The CKSEL0 Fuse together with the SUT1..0 Fuses select the start-up times as shown below.
Table 9-4. Start-up times for the oscillator clock selection
CKSEL0 SUT1..0 Start-up time from
power-down and
power-save
Additional delay
from reset (VCC =
5.0V)
Recommended
usage
0 00 258 CK
(1)
14CK + 4.1ms Ceramic resonator,
fast rising power
0 01 258 CK
(1)
14CK + 65ms Ceramic resonator,
slowly rising power
0 10 1K CK
(2)
14CK Ceramic resonator,
BOD enabled
0 11 1K CK
(2)
14CK + 4.1ms Ceramic resonator,
fast rising power
1 00 1K CK
(2)
14CK + 65ms Ceramic resonator,
slowly rising power
1 01 16K CK 14CK Ceramic resonator,
BOD enabled
Atmel ATmega16M1/32M1/64M1 [DATASHEET]
Atmel-8209F-ATmega16M1/32M1/64M1_Datasheet_Complete-10/2016
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