HD6432646 Hitachi, HD6432646 Datasheet - Page 753

• Manufacturer Part Number: HD6432646
• Description: (HD64F264x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

Table 21-2 Damping Resistance Value
Frequency (MHz)
R
Crystal Resonator: Figure 21-3 shows the equivalent circuit of the crystal resonator. Use a
crystal resonator that has the characteristics shown in table 18-3. The crystal resonator frequency
should not exceed 20 MHz.
Table 21-3 Crystal Resonator Parameters
Frequency (MHz)
R
C
Note 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 21-4.
When designing the board, place the crystal resonator and its load capacitors as close as possible
to the XTAL and EXTAL pins.
d
S
0
()
max (pF)
max ()
XTAL
Figure 21-3 Crystal Resonator Equivalent Circuit
Figure 21-4 Example of Incorrect Board Design
Avoid
4
500
4
120
7
C
C
L2
L1
L
Signal A Signal B
C
C
8
200
8
80
7
L
0
AT-cut parallel-resonance type
R
s
12
0
12
60
7
H8S/2646 Series
XTAL
EXTAL
EXTAL
16
0
16
50
7
20
0
20
40
7
719