Datasheet

333
ATmega169A/PA/329A/PA/649A/P/3290A/PA/6490A/P [DATASHEET]
8284E–AVR–02/2013
29.4 Clock characteristics
29.4.1 Calibrated internal RC oscillator accuracy
Notes: 1. Voltage range for Atmel ATmega169A/169PA/329A/329PA/649A/649P/3290A/3290PA/6490A/6490P.
29.4.2 External clock drive waveforms
Figure 29-3. External clock drive waveforms.
29.4.3 External clock drive
Table 29-12. Calibration accuracy of internal RC oscillator.
Frequency V
CC
Temperature Calibration accuracy
Factory calibration 8.0MHz 3V 25C±10%
User calibration 7.3 - 8.1MHz 1.8V - 5.5V
(1)
-40C - 85C±1%
V
IL1
V
IH1
Table 29-13. External clock drive.
Symbol Parameter
V
CC
= 1.8-5.5V V
CC
= 2.7-5.5V V
CC
= 4.5-5.5V
UnitsMin. Max. Min. Max. Min. Max.
1/t
CLCL
Oscillator
Frequency
04010020MHz
t
CLCL
Clock Period 1000 100 50
nst
CHCX
High Time 400 40 20
t
CLCX
Low Time 400 40 20
t
CLCH
Rise Time 2.0 1.6 0.5
s
t
CHCL
Fall Time 2.0 1.6 0.5
t
CLCL
Change in period
from one clock
cycle to the next
22 2%