HD6432345 Datasheet, PDF (622/907 Pages) Hitachi Semiconductor – H8S/2345 F-ZTAT Hardware Manual

18.3 Oscillator
Clock pulses can be supplied by connecting a crystal resonator, or by input of an external clock.
18.3.1 Connecting a Crystal Resonator
Circuit Configuration: A crystal resonator can be connected as shown in the example in figure
18.2. Select the damping resistance R_d according to table 18.2. An AT-cut parallel-resonance
crystal should be used.
C_L1
EXTAL
XTAL
R_d
C_L2
C_L1 = C_L2 = 10 to 22pF
Figure 18.2 Connection of Crystal Resonator (Example)
Table 18.2 Damping Resistance Value
Frequency (MHz)
R_d (Ω)
2
4
8
12
16
20
1k
500
200
0
0
0
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
C_L
L
R_s
EXTAL
C₀
AT-cut parallel-resonance type
Figure 18.3 Crystal Resonator Equivalent Circuit
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