attiny25v ATMEL Corporation, attiny25v Datasheet - Page 30

• Manufacturer Part Number: attiny25v
• Description: Microcontroller With 2/4/8k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

30
ATtiny25/45/85
Figure 6-5.
C1 and C2 should always be equal for both crystals and resonators. The optimal value of the
capacitors depends on the crystal or resonator in use, the amount of stray capacitance, and the
electromagnetic noise of the environment. Some initial guidelines for choosing capacitors for
use with crystals are given in
given by the manufacturer should be used.
Table 6-11.
Notes:
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 CKSEL0 Fuse together with the SUT1..0 Fuses select the start-up times as shown in
6-12.
Table 6-12.
CKSEL0
CKSEL3:1
100
0
0
0
0
1
101
110
111
(1)
1. This option should not be used with crystals, only with ceramic resonators.
SUT1:0
Crystal Oscillator Connections
Crystal Oscillator Operating Modes
Start-up Times for the Crystal Oscillator Clock Selection
00
01
10
11
00
Frequency Range (MHz)
Start-up Time from
0.4 - 0.9
0.9 - 3.0
3.0 - 8.0
1K (1024) CK
1K (1024)CK
1K (1024)CK
Power-down
8.0 -
Table 6-11
258 CK
258 CK
(1)
(1)
C2
C1
(2)
(2)
(2)
below. For ceramic resonators, the capacitor values
Additional Delay
Recommended Range for Capacitors C1 and
14CK + 64 ms
14CK + 64 ms
14CK + 4 ms
14CK + 4 ms
from Reset
XTAL2
XTAL1
GND
14CK
C2 for Use with Crystals (pF)
12 - 22
12 - 22
12 - 22
Recommended Usage
Ceramic resonator,
fast rising power
Ceramic resonator,
slowly rising power
Ceramic resonator,
BOD enabled
Ceramic resonator,
fast rising power
Ceramic resonator,
slowly rising power
–
Table
2586K–AVR–01/08
6-11.
Table