Table of Contents
Advertisement
Crystal Resonator: Figure 18-3 shows the equivalent circuit of the crystal resonator. Use a
crystal resonator that has the characteristics shown in table 18-3 and the same resonance frequency
as the system clock (ø).
XTAL
Table 18-3 Crystal Resonator Characteristics
Frequency (MHz)
R
max (Ω)
S
C
max (pF)
0
Note: * In planning stage
Notes on Board Design: When a crystal resonator is connected, the following points should be
noted:
Other signal lines should be routed away from the oscillator circuit to prevent induction from
interfering with correct oscillation. See figure 18-4.
When designing the board, place the crystal resonator and its load capacitors as close as possible
to the XTAL and EXTAL pins.
Avoid
L
Figure 18-3 Crystal Resonator Equivalent Circuit
2
4
500
120
7
7
Signal A Signal B
C
L2
C
L1
Figure 18-4 Example of Incorrect Board Design
C
L
R
s
AT-cut parallel-resonance type
C
0
8
12
80
60
7
7
H8S/2338 Series,
H8S/2328 Series, or
H8S/2318 Series
XTAL
EXTAL
EXTAL
16
20
50
40
7
7
25*
40
7
603
Advertisement
Table of Contents
