HD6433640 HITACHI [Hitachi Semiconductor], HD6433640 Datasheet - Page 92

• Manufacturer Part Number: HD6433640
• Description: H8/3644 Series Hardware Manual
• Manufacturer: HITACHI [Hitachi Semiconductor]

4.1
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.
4.1.1
Figure 4.1 shows a block diagram of the clock pulse generators.
4.1.2
The basic clock signals that drive the CPU and on-chip peripheral modules are ø and ø
the clock signals have names: ø is the system clock, ø
clock, and ø
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
The clock requirements differ from one module to another.
OSC
OSC
X
X
1
2
1
2
Overview
Block Diagram
System Clock and Subclock
System clock pulse generator
Subclock pulse generator
System clock
Subclock
oscillator
W
oscillator
is the watch clock.
Figure 4.1 Block Diagram of Clock Pulse Generators
Section 4 Clock Pulse Generators
(f
(f )
ø
ø
OSC
W
OSC
W
)
System clock
(1/2, 1/4, 1/8)
divider (1/2)
Subclock
divider
ø
ø /2
ø /4
ø /8
OSC
W
W
W
System clock
(1/64, 1/32,
W
1/16, 1/8)
/2
/2, ø
divider
SUB
W
/4, ø
is the subclock, ø
W
ø
ø
ø
ø
OSC
OSC
OSC
OSC
/8, ø
/128
/64
/32
/16
W
/16, ø
W
OSC
/32, ø
Prescaler W
Prescaler S
(13 bits)
ø
ø
(5 bits)
is the oscillator
SUB
W
/64, and ø
SUB
. Four of
ø/2
to
ø/8192
ø /2
ø /4
ø /8
to
ø /128
W
W
W
W
W
/128.
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