Datasheet

Section 5 Clock Pulse Generator
REJ09B0465-0300 Rev. 3.00 Page 135 of 982
Sep 17, 2010
H8S/20103, H8S/20203, H8S/20223, H8S/20115, H8S/20215, H8S/20235 Group
5.4 Main Clock Oscillator
This LSI has two methods to supply external clock pulses into it: connecting a crystal or ceramic
resonator, and an external clock. For setting PJ0/OSC1 and PJ1/OSC2/CLKOUT for a crystal
resonator or an external clock, see section 10.10.1, Port Mode Register J (PMRJ). Figure 5.12
shows a block diagram of the Main clock oscillator.
STBY
[Legend]
STBY: Standby mode
OSC2
OSC1
Figure 5.12 Block Diagram of Main Clock Oscillator
5.4.1 Connecting Crystal Resonator
Figure 5.13 shows an example of connecting a crystal resonator. An AT-cut parallel-resonance
crystal resonator should be used. A damping resistor Rd should be added, if necessary. Since the
resistor values vary depending on the resonator, use values recommended by the resonator
manufacturer.
C
1
C
2
PJ0/OSC1
PJ1/OSC2/CLKOUT
C
1
= C
2
= 10 to 22 pF
Rd
Figure 5.13 Example of Connection to Crystal Resonator