Section 10 Clock Pulse Generator; Overview - Hitachi H8/3152 Hardware Manual

Section 10 Clock Pulse Generator

10.1

Overview

The H8/3150 series includes an on-chip clock divider that generates the system clock for CPU (ø)
from an external clock input. The external clock is input to the CLK pin.
The CPU system clock frequency is one-half the external clock frequency when supplied through
the divider, or it is the same frequency as the external clock frequency when directly supplied. The
frequency can be selected by the CPUCS0 bit in the system control register (SYSCR).
CPUCS0
1/2 divider
System clock
External clock
φ
for CPU ( )
(CLK)
Figure 10.1 Block Diagram of Clock Pulse Generator
CLK
State
φ
Figure 10.2 Relationship of System Clock and External Clock Input
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