Datasheet

Table Of Contents
Section 2 CPU
Rev. 2.00 Jul. 04, 2007 Page 40 of 692
REJ09B0309-0200
2.7 CPU States
There are four CPU states: the reset state, program execution state, program halt state, and
exception-handling state. The program execution state includes active (high-speed or medium-
speed) mode and subactive mode. For the program halt state, there are sleep (high-speed or
medium-speed) mode, standby mode, watch mode, and subsleep mode. These states are shown in
figure 2.11. Figure 2.12 shows the state transitions. For details on program execution state and
program halt state, refer to section 6, Power-Down Modes. For details on exception handling, refer
to section 3, Exception Handling.
CPU state Reset state
Program execution state Active (high-speed) mode
Active (medium-speed) mode
Power-down modes
Subactive mode
Sleep (high-speed) mode
Sleep (medium-speed) mode
Standby mode
Watch mode
Subsleep mode
Program halt state
A state in which the CPU
operation is stopped to
reduce power consumption
A transient state in which the CPU changes
the processing flow due to a reset or an interrupt
Exception-handling state
The CPU is initialized
The CPU executes successive program
instructions at high speed,
synchronized by the system clock
The CPU executes successive
program instructions at
reduced speed, synchronized
by the system clock
The CPU executes successive
program instructions at reduced
speed, synchronized by the subclock
Figure 2.11 CPU Operating States