HD6475348R Datasheet, PDF (153/487 Pages) Hitachi Semiconductor – Single-Chip Microcomputer

Section 8 Clock Pulse Generator
8.1 Overview
The H8/534 and H8/536 have a built-in clock pulse generator (CPG) consisting of an oscillator
circuit, a system (ø) clock divider, an E clock divider, and a group of prescalers. The prescalers
generate clock signals for the on-chip supporting modules.
8.1.1 Block Diagram
XTAL
EXTAL
Oscillator
circuit
Divider
÷2
Divider
÷8
CPG
Prescalers
ø
E
ø/2 to ø/4096
Figure 8-1 Block Diagram of Clock Pulse Generator
8.2 Oscillator Circuit
If an external crystal is connected across the EXTAL and XTAL pins, the on-chip oscillator circuit
generates a clock signal for the system clock divider. Alternatively, an external clock signal can
be applied to the EXTAL pin.
Connecting an External Crystal
(1) Circuit Configuration: An external crystal can be connected as in the example in figure 8-2.
An AT-cut parallel resonating crystal should be used.
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