ATMEGA8L ATMEL [ATMEL Corporation], ATMEGA8L Datasheet - Page 239

• Manufacturer Part Number: ATMEGA8L
• Description: 8-bit AVR with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

External Clock Drive
Waveforms
External Clock Drive
2486M–AVR–12/03
Figure 114. External Clock Drive Waveforms
Table 99. External Clock Drive
Table 100. External RC Oscillator, Typical Frequencies
Notes:
Symbol
1/t
t
t
t
t
t
CLCL
CHCX
CLCX
CLCH
CHCL
t
CLCL
CLCL
1. R should be in the range 3 k - 100 k , and C should be at least 20 pF. The C values
2. The frequency will vary with package type and board layout.
given in the table includes pin capacitance. This will vary with package type.
Parameter
Oscillator Frequency
Clock Period
High Time
Low Time
Rise Time
Fall Time
Change in period from one
clock cycle to the next
V
R [k ]
IL1
100
33
10
V
IH1
(1)
V
CC
Min
125
50
50
0
= 2.7V to
C [pF]
47
22
22
Max
1.6
1.6
5.5
8
2
V
V
CC
62.5
Min
25
25
0
ATmega8(L)
= 4.5V to
650 kHz
2.0 MHz
87 kHz
Max
0.5
0.5
16
5.5
2
f
(2)
V
Units
MHz
ns
ns
ns
%
s
s
239