Atmel ATmega328P Xplained Mini MEGA328P-XMINI MEGA328P-XMINI Data Sheet
Product codes
MEGA328P-XMINI
30
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET]
Atmel-8271H-AVR- ATmega-Datasheet_08/2014
Notes: 1.
This is the recommended CKSEL settings for the difference frequency ranges.
2.
This option should not be used with crystals, only with ceramic resonators.
3.
If the crystal frequency exceeds the specification of the device (depends on V
CC
), the CKDIV8 Fuse can be
programmed in order to divide the internal frequency by 8. It must be ensured that the resulting divided clock
meets the frequency specification of the device.
meets the frequency specification of the device.
Notes: 1.
These options should only be used when not operating close to the maximum frequency of the device, and
only if frequency stability at start-up is not important for the application. These options are not suitable for
crystals.
only if frequency stability at start-up is not important for the application. These options are not suitable for
crystals.
2.
These options are intended for use with ceramic resonators and will ensure frequency stability at start-up. They
can also be used with crystals when not operating close to the maximum frequency of the device, and if
frequency stability at start-up is not important for the application.
can also be used with crystals when not operating close to the maximum frequency of the device, and if
frequency stability at start-up is not important for the application.
9.4
Full Swing Crystal Oscillator
Pins 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
use as an On-chip Oscillator, as shown in
. Either a quartz crystal or a ceramic resonator
may be used.
Table 9-3.
Low Power Crystal Oscillator Operating Modes
Frequency Range
(MHz)
Recommended Range for
Capacitors C1 and C2 (pF)
CKSEL3...1
0.4 - 0.9
–
100
0.9 - 3.0
12 - 22
101
3.0 - 8.0
12 - 22
110
8.0 - 16.0
12 - 22
111
Table 9-4.
Start-up Times for the Low Power Crystal Oscillator Clock Selection
Oscillator Source /
Power Conditions
Power Conditions
Start-up Time from
Power-down and
Power-save
Additional Delay
from Reset
(V
CC
= 5.0V)
CKSEL0
SUT1...0
Ceramic resonator, fast
rising power
rising power
258 CK
14CK + 4.1ms
0
00
Ceramic resonator, slowly
rising power
rising power
258 CK
14CK + 65ms
0
01
Ceramic resonator, BOD
enabled
enabled
1K CK
14CK
0
10
Ceramic resonator, fast
rising power
rising power
1K CK
14CK + 4.1ms
0
11
Ceramic resonator, slowly
rising power
rising power
1K CK
14CK + 65ms
1
00
Crystal Oscillator, BOD
enabled
enabled
16K CK
14CK
1
01
Crystal Oscillator, fast
rising power
rising power
16K CK
14CK + 4.1ms
1
10
Crystal Oscillator, slowly
rising power
rising power
16K CK
14CK + 65ms
1
11