HD643303x Hitachi, HD643303x Datasheet - Page 61

• Manufacturer Part Number: HD643303x
• Description: Hitachi Microcomputer
• Manufacturer: Hitachi

2.8 Processing States
2.8.1 Overview
The H8/300H CPU has five processing states: the program execution state, exception-handling
state, power-down state, reset state, and bus-released state. The power-down state includes sleep
mode, software standby mode, and hardware standby mode. Figure 2-11 classifies the processing
states. Figure 2-13 indicates the state transitions.
Processing states
Exception-handling state
Program execution state
The CPU executes program instructions in sequence
A transient state in which the CPU executes a hardware sequence
(saving PC and CCR, fetching a vector, etc.) in response to a reset,
interrupt, or other exception
The CPU and all on-chip supporting modules are initialized and halted
The CPU is halted to conserve power
Power-down state
Reset state
Figure 2-11 Processing States
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Hardware standby mode
Software standby mode
Sleep mode