Oscillator; Connecting A Crystal Oscillator; Figure 21.2 Connection Of Crystal Oscillator (Example); Figure 21.3 Crystal Oscillator Equivalent Circuit - Renesas H8S/2368 Series Hardware Manual

21.2

Oscillator

Clock pulses can be supplied by connecting a crystal resonator, or by input of an external clock.
21.2.1

Connecting a Crystal Oscillator

A crystal oscillator can be connected as shown in the example in figure 21.2. Select the damping
resistance R according to table 21.1. An AT-cut parallel-resonance type should be used.
d
When a clock is supplied with a crystal resonator connected, the frequency of the crystal resonator
should be 8 MHz to 25 MHz.
Figure 21.3 shows the equivalent circuit of the crystal oscillator. Use a crystal oscillator that has
the characteristics shown in table 21.2.
EXTAL
XTAL

Figure 21.2 Connection of Crystal Oscillator (Example)

Table 21.1 Damping Resistance Value

Frequency (MHz)
R (Ω)
d
XTAL
Rev. 2.00, 05/03, page 678 of 820
R
d
8 12
200 0
C
L
C

Figure 21.3 Crystal Oscillator Equivalent Circuit

C
L1
C C = C
L2 L1
16
0
L
R
s
EXTAL
AT-cut parallel-resonance type
0
= 10 to 22 pF
L2
20 25
0 0