HD643303x Hitachi, HD643303x Datasheet - Page 421

• Manufacturer Part Number: HD643303x
• Description: Hitachi Microcomputer
• Manufacturer: Hitachi

15.2 Oscillator Circuit
Clock pulses can be supplied by connecting a crystal resonator, or by input of an external clock
signal.
15.2.1 Connecting a Crystal Resonator
Circuit Configuration: A crystal resonator can be connected as in the example in figure 15-2.
The damping resistance Rd should be selected according to table 15-1. An AT-cut parallel-
resonance crystal should be used.
Table 15-1 Damping Resistance Value
Frequency (MHz)
Rd (Ω)
Crystal Resonator: Figure 15-3 shows an equivalent circuit of the crystal resonator. The crystal
resonator should have the characteristics listed in table 15-2.
XTAL
Figure 15-2 Connection of Crystal Resonator (Example)
EXTAL
XTAL
Figure 15-3 Crystal Resonator Equivalent Circuit
2
1 k
L
Rd
4
500
C
L
C
C
L1
L2
406
8
200
C
O
10
0
AT-cut parallel-resonance type
C
L1
Rs
= C
12
0
L2
= 10 pF to 22 pF
16
0
EXTAL