Renesas Hitachi H8S/2191, Hardware Manual

Page: 79 / 1065

Rev. 2.0, 11/00, page 52 of 1037
2.8 Processing States
2.8.1 Overview
The CPU has four main processing states: the reset state, exception-handling state, program
execution state, and power-down state. Figure 2.14 shows a diagram of the processing states.
Figure 2.15 indicates the state transitions.
Reset state
The CPU and all on-chip supporting modules have been initialized and are stopped.
Exception-handling
state
A transient state in which the CPU changes the normal processing flow in response
to a reset, interrupt or trap instruction.
Program execution
state
The CPU executes program instructions in sequence.
Power-down state
CPU operation is stopped
to conserve power.
*
Sleep mode
Standby mode
Processing
states
Note:
* The power-down state also includes a medium-speed mode, modue stop mode, sub-active mode,
sub-sleep mode and watch mode.
Figure 2.14 Processing States