Section 13. Clock Pulse Generator
13.1 Overview
The H8/329 Series has a built-in clock pulse generator (CPG) consisting of an oscillator circuit, a
system (Ø) clock divider, and a prescaler. The prescaler generates clock signals for the on-chip
supporting modules.
13.1.1 Block Diagram
Figure 13-1. Block Diagram of Clock Pulse Generator
13.2 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
①
Circuit Configuration: An external crystal can be connected as in the example in figure 13-2.
An AT-cut parallel resonating crystal should be used.
CPG
Oscillator
circuit
Divider
÷ 2
Prescaler
ø
/2 to
ø
/4096
ø
XTAL
EXTAL
247
Содержание H8/326 Series
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