H8SX1663 datasheet(1020/1158 Pages) RENESAS

1020 / 1158 page

Section 22 Clock Pulse Generator

Rev.1.00 Jun. 07, 2006 Page 968 of 1102

REJ09B0294-0100

External

clock

One cycle (worst case)

after the bus cycle completion

Operating clock

specified in SCKCR

Operating clock changed

CPU

Bus master

Figure 22.9 Clock Modification Timing

22.6.2

Notes on Resonator

Since various characteristics related to the resonator are closely linked to the user's board design,

thorough evaluation is necessary on the user's part, using the resonator connection examples

shown in this section as a reference. As the parameters for the resonator will depend on the

floating capacitance of the resonator and the mounting circuit, the parameters should be

determined in consultation with the resonator manufacturer. The design must ensure that a voltage

exceeding the maximum rating is not applied to the resonator pin.

22.6.3

Notes on Board Design

When using the crystal resonator, place the crystal resonator and its load capacitors as close to the

XTAL and EXTAL pins as possible. Other signal lines should be routed away from the oscillation

circuit as shown in Figure 22.10 to prevent induction from interfering with correct oscillation.

CL2

Signal A Signal B

CL1

This LSI

XTAL

EXTAL

Inhibited

Figure 22.10 Note on Board Design for Oscillation Circuit

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