Oscillator; Connecting A Crystal Resonator - Renesas Hitachi H8S/2194 Series Hardware Manual

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.
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
Table 10.2 Crystal Resonator Parameters
Frequency (MHz)
R max (Ω)
S
C max (pF)
O
Rev. 2.0, 11/00, page 226 of 1037
OSC1
R
f
OSC2
L
Figure 10.3 Crystal Resonator Equivalent Circuit
C
L1
R 1M
f =
C C C
L2 L1 =
C
L
R
s
OSC2
AT-cut parallel-resonance type
C
0
8
80
7
± 20%
= 10 to 22pF
L2
10
60
7