D12320VF25V Datasheet, PDF (96/1146 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 2 CPU
2.8 Processing States
2.8.1 Overview
The CPU has five main processing states: the reset state, exception handling state, program
execution state, bus-released state, and power-down state. Figure 2.11 shows a diagram of the
processing states. Figure 2.12 indicates the state transitions.
Processing
states
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.
Bus-released state
The external bus has been released in response to a bus
request signal from a bus master other than the CPU.
Sleep mode
Power-down state
CPU operation is stopped
to conserve power.*
Software standby
mode
Hardware standby
mode
Note: * The power-down state also includes a medium-speed mode, module stop mode etc.
Figure 2.11 Processing States
Rev.7.00 Feb. 14, 2007 page 62 of 1108
REJ09B0089-0700