HD6417750RF240V Datasheet, PDF (516/606 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

Section 19 Clock Pulse Generator
19.2 Oscillator
Clock pulses can be supplied by connecting a crystal resonator, or by input of an external clock. In
either case, the input clock should not exceed 20 MHz.
19.2.1 Connecting a Crystal Resonator
Circuit Configuration: A crystal resonator can be connected as shown in the example in figure
19.2. Select the damping resistance R_d according to table 19.1. 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 19.2 Connection of Crystal Resonator (Example)
Table 19.1 Damping Resistance Value
Frequency (MHz)
R_d (Ω)
4
8
10
12
16
20
500
200
0
0
0
0
Figure 19.3 shows the equivalent circuit of the crystal resonator. Use a crystal resonator that has
the characteristics shown in table 19.2.
XTAL
C_L
L
R_s
EXTAL
C₀ ^{AT-cut parallel-resonance type}
Figure 19.3 Crystal Resonator Equivalent Circuit
Rev. 7.00 Sep. 11, 2009 Page 480 of 566
REJ09B0211-0700