Datasheet

330
8011Q–AVR–02/2013
ATmega164P/324P/644P
25.3 Clock Characteristics
Notes: 1. Voltage range for ATmega164PV/324PV/644PV.
2. Voltage range for ATmega164P/324P/644P.
25.3.1 External Clock Drive Waveforms
Figure 25-3. External Clock Drive Waveforms
25.3.2 External Clock Drive
Table 25-4. Calibration Accuracy of Internal RC Oscillator
Frequency V
CC
Temperature Calibration Accuracy
Factory
Calibration
8.0 MHz 3V 25C ±10%
User
Calibration
7.3 MHz - 8.1 MHz
1.8V - 5.5V
(1)
2.7V - 5.5V
(2)
-40C - 85C±1%
V
IL1
V
IH1
Table 25-5. External Clock Drive
Symbol Parameter
V
CC
= 1.8V - 5.5V V
CC
= 2.7V - 5.5V V
CC
= 4.5V - 5.5V
UnitsMin. Max. Min. Max. Min. Max.
1/t
CLCL
Oscillator Frequency 0 4 0 10 0 20 MHz
t
CLCL
Clock Period 250 100 50
nst
CHCX
High Time 100 40 20
t
CLCX
Low Time 100 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%