HD6473228P10V Datasheet, PDF (234/301 Pages) Renesas Technology Corp – Regarding the change of names mentioned in the document, such as Hitachi Electric and Hitachi XX, to Renesas Technology Corp

Section 14. Clock Pulse Generator
14.1 Overview
The H8/325 series chips have a built-in clock pulse generator (CPG) consisting of an oscillator
circuit, a system clock divider, an E clock divider, and a prescaler. The prescaler generates clock
signals for the on-chip supporting modules.
14.1.1 Block Diagram
CPG
XTAL
EXTAL
Oscillator
circuit
Divider
÷2
Divider
÷8
Prescaler
Ø
E
Ø/2 to Ø/4096
Figure 14-1. Block Diagram of Clock Pulse Generator
14.2 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.
(1) Connecting an External Crystal
ΠCircuit Configuration: An external crystal can be connected as in the example in figure 14-2.
An AT-cut parallel resonating crystal should be used.
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