Rainbow Electronics ATmega128L - Manual (Page 312)

312
ATmega128(L)
2467B–09/01
External Clock Drive
Waveforms Figure 152. External Clock Drive Waveforms
External Clock Drive
Note: R should be in the range 3 k Ω - 100 kΩ, and C should be at least 20 pF. The C values
given in the table includes pin capacitance. This will vary with package type.
V
IL1
V
IH1
Table 133. External Clock Drive
Symbol Parameter
V
CC
= 2.7V to 5.5 V V
CC
= 4.5V to 5.5 V
Units Min Max Min Max
1/t
CLCL
Oscillator Frequency 0 TBD 0 TBD MHz
t
CLCL
Clock Period TBD TBD ns
t
CHCX
High Time TBD TBD ns
t
CLCX
Low Time TBD TBD ns
t
CLCH
Rise Time 1.6 0.5
µs
t
CHCL
Fall Time 1.6 0.5 µs
Table 134. External RC Oscillator, Typical Frequencies
R [k Ω] C [pF] f
100 70 TBD
31.5 20 TBD
6.5 20 TBD