HD6473847RHV Datasheet, PDF (128/546 Pages) Renesas Technology Corp – Renesas 8-Bit Single-Chip Microcomputer H8 Family / H8/300L Super Low Power Series

Section 4 Clock Pulse Generators
4.3 System Clock Generator
Clock pulses can be supplied to the system clock divider either by connecting a crystal or ceramic
resonator, or by providing external clock input. Figure 4.3 shows a block diagram of the system
clock generator.
As shown in figure 4.2, the H8/38104 Group supports selection between a system clock oscillator
and an on-chip oscillator. See section 4.3.4, on-chip oscillator selection method, for information
on selecting the on-chip oscillator.
OSC2
OSC1
LPM
Note: LPM: Power-down mode (standby mode, subactive mode,
subsleep mode, watch mode)
Figure 4.3 Block Diagram of System Clock Generator
4.3.1 Connecting Crystal Resonator
Figure 4.4(1) shows a typical method of connecting a crystal oscillator to the H8/3802 Group, and
figure 4.4(2) shows a typical method of connecting a crystal oscillator to the H8/38004, H8/38104
and H8/38002S Group. Figure 4.5 shows the equivalent circuit of a crystal resonator. A resonator
having the characteristics given in table 4.1 should be used.
OSC1
Rf
OSC2
C₁
Frequency
Manufacturer
C1, C2 Recommendation Value
C₂
4.19 MHz NIHON DEMPA KOGYO CO., LTD.
C₁ = C₂ = 12 pF ±20%
Rf = 1 MΩ ±20%
12 pF ±20%
Note: Consult with the crystal resonator manufacturer
to determine the circuit constants.
Figure 4.4(1) Typical Connection to Crystal Resonator (H8/3802 Group)
Rev. 7.00 Mar. 08, 2010 Page 96 of 510
REJ09B0024-0700