HD6413007F20 Datasheet, PDF (578/798 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

18. Clock Pulse Generator
18.2 Oscillator Circuit
Clock pulses can be supplied by connecting a crystal resonator, or by input of an external clock
signal.
18.2.1 Connecting a Crystal Resonator
Circuit Configuration: A crystal resonator can be connected as in the example in figure 18.2.
The damping resistance Rd should be selected according to table 18.1. An AT-cut parallel-
resonance crystal should be used.
C_L1
EXTAL
XTAL
Rd
C_L2
C_L1 = C _L2 = 10 pF to 22 pF
Figure 18.2 Connection of Crystal Resonator (Example)
Table 18.1 Damping Resistance Value
Damping
Resistance
Value
2
2<f≤4
4<f≤8
Frequency f (MHz)
8 < f ≤ 10 10 < f ≤ 13 13 < f ≤ 16 16 < f ≤ 18 18 < f ≤ 20
Rd (Ω)
1k
500
200
0
0
0
0
0
Note: A crystal resonator between 2 MHz and 20 MHz can be used. If the chip is to be operated
at less than 2 MHz, the on-chip frequency divider should be used. (A crystal resonator of
less than 2 MHz cannot be used.)
Crystal Resonator: Figure 18.3 shows an equivalent circuit of the crystal resonator. The crystal
resonator should have the characteristics listed in table 18.2.
Rev.5.00 Sep. 12, 2007 Page 548 of 764
REJ09B0396-0500