Renesas H8SX series, Hardware Manual, Page: 703 / 846

Section 18 Clock Pulse Generator
Rev. 3.00 Mar. 14, 2006 Page 665 of 804
REJ09B0104-0300
18.2 Oscillator
Clock pulses can be supplied by connecting a crystal resonator, or by input of an external clock.
18.2.1 Connecting Crystal Resonator
A crystal resonator can be connected as shown in the example in figure 18.2. Select the damping
resistance R
d
according to table 18.1. An AT-cut parallel-resonance type should be used.
When the clock is provided by connecting a crystal resonator, a crystal resonator having a
frequency of 4 to 9 MHz should be connected.
EXTAL
XTAL
R
d
C
L2
C
L1
10 pF
≤
C
L1
= C
L2
≤
22 pF
Figure 18.2 Connection of Crystal Resonator (Example)
Table 18.1 Damping Resistance Value
Frequency (MHz) 4 6 8 9
R
d
(
Ω
) 500 300 200 100
Figure 18.3 shows an equivalent circuit of the crystal resonator. Use a crystal resonator that has
the characteristics shown in table 18.2.
XTAL
C
L
AT-cut parallel-resonance type
EXTAL
C
0
L R
s
Figure 18.3 Crystal Resonator Equivalent Circuit
Downloaded from Elcodis.com electronic components distributor