Oscillator; Connecting Crystal Resonator; Figure 18.2 Connection Of Crystal Resonator (Example); Figure 18.3 Crystal Resonator Equivalent Circuit - Renesas H8SX/1500 Series Hardware Manual

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 according to table 18.1. An AT-cut parallel-resonance type should be used.
d
When the clock is provided by connecting a crystal resonator, a crystal resonator having a
frequency of 4 to 9 MHz should be connected.

Figure 18.2 Connection of Crystal Resonator (Example)

Table 18.1 Damping Resistance Value

Frequency (MHz)
R (Ω)
d
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
EXTAL
XTAL
R
d
4
500
L

Figure 18.3 Crystal Resonator Equivalent Circuit

C
L1
10 pF ≤ C
C
L2
6
300
C
L
R
s
AT-cut parallel-resonance type
C
0
Rev. 3.00 Mar. 14, 2006 Page 665 of 804
Section 18 Clock Pulse Generator
≤ 22 pF
= C
L1 L2
8 9
200 100
EXTAL
REJ09B0104-0300