Figure 20.3 Crystal Resonator Equivalent Circuit; Figure 20.4 Oscillator Circuit Block Board Design Precautions; Table 20.2 Crystal Resonator Parameters - Hitachi H8/3062 Hardware Manual

Crystal Resonator: Figure 20.3 shows an equivalent circuit of the crystal resonator. The crystal
resonator should have the characteristics listed in table 20.2.
XTAL

Table 20.2 Crystal Resonator Parameters

Frequency (MHz)
Rs max (Ω)
Co (pF)
Use a crystal resonator with a frequency equal to the system clock frequency (φ).
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 20.4.
When the board is designed, the crystal resonator and its load capacitors should be placed as close
as possible to the XTAL and EXTAL pins.
Avoid
C
C

Figure 20.4 Oscillator Circuit Block Board Design Precautions

C
L

Figure 20.3 Crystal Resonator Equivalent Circuit

2 4 8
500 120 80
Signal A
L2
L1
L
AT-cut parallel-resonance type
C
0
10 12
70 60
7 pF max
Signal B
Rs
16 18 20
50 40 40
H8/3062 Series
XTAL
EXTAL
EXTAL
25
40
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