HD64F2357F20V Datasheet, PDF (693/1049 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-chip Microcomputer H8S Family / H8S/2300 Series

20.3 Oscillator
Clock pulses can be supplied by connecting a crystal resonator, or by input of an external clock.
20.3.1 Connecting a Crystal Resonator
Circuit Configuration: A crystal resonator can be connected as shown in the example in figure 20-2. Select the damping
resistance R_d according to table 20-2. An AT-cut parallel-resonance crystal should be used.
C_L1
EXTAL
XTAL
R_d
C_L2
C_L1 = C_L2 = 10 to 22 pF
Figure 20-2 Connection of Crystal Resonator (Example)
Table 20-2 Damping Resistance Value
Frequency (MHz)
R_d (Ω)
2
4
8
10
12
16
20
1k
500
200
0
0
0
0
Crystal Resonator: Figure 20-3 shows the equivalent circuit of the crystal resonator. Use a crystal resonator that has the
characteristics shown in table 20-3 and the same resonance frequency as the system clock (ø).
XTAL
C_L
L
R_s
EXTAL
C₀
AT-cut parallel-resonance type
Figure 20-3 Crystal Resonator Equivalent Circuit
Table 20-3 Crystal Resonator Parameters
Frequency (MHz)
R_S max (Ω)
C₀ max (pF)
2
4
8
10
12
16
20
500
120
80
70
60
50
40
7
7
7
7
7
7
7
Rev.6.00 Oct.28.2004 page 663 of 1016
REJ09B0138-0600H