ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 27

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ATmega88PA Automotive

Manufacturer Part Number
ATmega88PA Automotive
Description
Manufacturer
Atmel Corporation
7.4
7701E–AVR–02/11
Crystal Oscillator
XTAL1 and XTAL2 are input and output, respectively, of an inverting amplifier which can be
configured for use as an On-chip Oscillator, as shown in Figure 7-2. Either a quartz crystal or
a ceramic resonator may be used.
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
values given by the manufacturer should be used.
Figure 7-2.
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
page
Table 7-3.
Notes:
The CKSEL0 Fuse together with the SUT1..0 Fuses select the start-up times as shown in
Table 7-4 on page
CKSEL3..1
100
101
110
111
27.
(1)
1. This option should not be used with crystals, only with ceramic resonators.
Crystal Oscillator Connections
Crystal Oscillator Operating Modes
28.
Frequency Range (MHz)
Atmel ATtiny24/44/84 [Preliminary]
0.4 - 0.9
0.9 - 3.0
3.0 - 8.0
8.0 -
Table 7-3 on page
C2
C1
Recommended Range for Capacitors C1 and
27. For ceramic resonators, the capacitor
XTAL2
XTAL1
GND
C2 for Use with Crystals (pF)
12 - 22
12 - 22
12 - 22
Table 7-3 on
27

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