HD6433308 Datasheet, PDF (273/349 Pages) Hitachi Semiconductor – Hitachi Single-Chip MicroComputer

Section 16. Clock Pulse Generator
16.1 Overview
The H8/330 chip has a built-in clock pulse generator (CPG) consisting of an oscillator circuit, a
system (Ø) clock divider, an E clock divider, and a prescaler. The prescaler generates clock signals
for the on-chip supporting modules.
16.1.1 Block Diagram
CPG
XTAL
EXTAL
Oscillator
circuit
Divider
÷2
Divider
÷8
Prescaler
Ø
E
Ø/2 to Ø/4096
Figure 16-1. Block Diagram of Clock Pulse Generator
16.2 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
x Circuit Configuration: An external crystal can be connected as in the example in Figure 16-2.
An AT-cut parallel resonating crystal should be used.
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