Renesas Hitachi H8S/2191, Hardware Manual

Page: 253 / 1065

Rev. 2.0, 11/00, page 226 of 1037
10.3 Oscillator
Clock pulses can be supplied by connecting a crystal resonator, or by input of an external clock.
10.3.1 Connecting a Crystal Resonator
(1) Circuit Configuration
A crystal resonator can be connected as shown in the example in figure 10.2. An AT-cut
parallel-resonance crystal should be used.
OSC1
OSC2
R
f
C
L2
C
L1
C
L1 =
C
L2
= 10 to 22pF
R
f =
1M ± 20%
Figure 10.2 Connection of Crystal Resonator (Example)
(2) Crystal Resonator
Figure 10.3 shows the equivalent circuit of the crystal resonator. Use a crystal resonator that
has the characteristics shown in table 10.2 and the same frequency as the system clock (
φ
).
OSC1
C
L
AT-cut parallel-resonance type
OSC2
C
0
L R
s
Figure 10.3 Crystal Resonator Equivalent Circuit
Table 10.2 Crystal Resonator Parameters
Frequency (MHz) 8 10
R
S
max (
Ω
) 80 60
C
O
max (pF) 7 7