ATMEGA325-16AJ ATMEL [ATMEL Corporation], ATMEGA325-16AJ Datasheet - Page 27

• Manufacturer Part Number: ATMEGA325-16AJ
• Description: 8-bit Microcontroller with In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

2570A–AVR–09/04
Figure 13. Crystal Oscillator Connections
The Oscillator can operate in three different modes, each optimized for a specific fre-
quency range. The operating mode is selected by the fuses CKSEL3..1 as shown in
Table 5.
Table 5. Crystal Oscillator Operating Modes
Notes:
The CKSEL0 Fuse together with the SUT1..0 Fuses select the start-up times as shown
in Table 6.
Table 6. Start-up Times for the Crystal Oscillator Clock Selection
CKSEL0
0
0
0
0
1
1
1
1
CKSEL3..1
100
1. This option should not be used with crystals, only with ceramic resonators.
101
110
111
(1)
SUT1..0
00
01
10
11
00
01
10
11
Start-up Time from
Frequency Range
Power-down and
Power-save
258 CK
258 CK
1K CK
1K CK
1K CK
0.4 - 0.9
0.9 - 3.0
3.0 - 8.0
16K CK
16K CK
16K CK
(MHz)
8.0 -
C2
C1
(2)
(2)
(2)
(1)
(1)
ATmega325/3250/645/6450
Recommended Range for Capacitors C1
Additional Delay
14CK + 4.1 ms
14CK + 4.1 ms
14CK + 4.1 ms
14CK + 65 ms
14CK + 65 ms
14CK + 65 ms
(V
from Reset
and C2 for Use with Crystals (pF)
CC
14CK
14CK
= 5.0V)
XTAL2
XTAL1
GND
12 - 22
12 - 22
12 - 22
–
Recommended
Usage
Ceramic resonator,
fast rising power
slowly rising power
Ceramic resonator,
BOD enabled
Ceramic resonator,
fast rising power
slowly rising power
Crystal Oscillator,
BOD enabled
rising power
Crystal Oscillator,
slowly rising power
Ceramic resonator,
Ceramic resonator,
Crystal Oscillator, fast
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