Datasheet

209
ATmega323(L)
1457E–11/01
External Clock Drive
Waveforms
Figure 106. External Clock Drive Waveforms
External Clock Drive
Note: R should be in the range 3kΩ - 100kΩ, and C should be at least 20pF. The C values
given in the table includes pin capacitance. This will vary with package type.
lL1
lH1
Table 72. External Clock Drive
Symbol Parameter
V
CC
= 2.7V to 5.5VV
CC
= 4.0V to 5.5V
UnitsMin Max Min Max
1/t
CLCL
Oscillator Frequency0408MHz
t
CLCL
Clock Period 250 125 ns
t
CHCX
High Time 100 50 ns
t
CLCX
Low Time 100 50 ns
t
CLCH
Rise Time 1.6 0.5 µs
t
CHCL
Fall Time 1.6 0.5 µs
Table 73. External RC Oscillator, Typical Frequencies
R [kΩ]C [pF]f
100 70 TBD
31.5 20 TBD
6.5 20 TBD