Datasheet

352
8284D–AVR–6/11
ATmega169A/PA/329A/PA/3290A/PA/649A/P/6490A/P
29.4 Clock Characteristics
29.4.1 Calibrated Internal RC Oscillator Accuracy
Notes: 1. Voltage range for 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
μs
t
CHCL
Fall Time 2.0 1.6 0.5
Δt
CLCL
Change in period
from one clock
cycle to the next
22 2%