Clock Pulse Generators; Overview; Block Diagram; System Clock And Subclock - Hitachi H8/3827R Series Hardware Manual

Table of Contents

Clock oscillator circuitry (CPG: clock pulse generator) is provided on-chip, including both a

system clock pulse generator and a subclock pulse generator. The system clock pulse generator

consists of a system clock oscillator and system clock dividers. The subclock pulse generator

consists of a subclock oscillator circuit and a subclock divider.

Figure 4.1 shows a block diagram of the clock pulse generators.

System clock

System clock pulse generator

Subclock pulse generator

Figure 4.1 Block Diagram of Clock Pulse Generators

The basic clock signals that drive the CPU and on-chip peripheral modules are ø and ø

of the clock signals have names: ø is the system clock, ø

clock, and ø

is the watch clock.

The clock signals available for use by peripheral modules are ø/2, ø/4, ø/8, ø/16, ø/32, ø/64, ø/128,

ø/256, ø/512, ø/1024, ø/2048, ø/4096, ø/8192, ø

/128. The clock requirements differ from one module to another.

Section 4 Clock Pulse Generators

System clock

divider (1/2)

(1/2, 1/4, 1/8)

is the subclock, ø

is the oscillator