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Rev. 1.0, 07/01, page 35 of 372
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 mode and subactive mode.
For the program halt state there are a sleep mode, standby mode, and sub-sleep 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
processing, refer to section 3, Exception Handling.
CPU state Reset state
Program
execution state
Program halt state
Exception-
handling state
Active
(high speed) mode
Subactive mode
Sleep mode
Subsleep mode
Power-down
modes
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 subclock
A state in which some
or all of the chip
functions are stopped
to conserve power
A transient state in which the CPU changes
the processing flow due to a reset or an interrupt
The CPU is initialized
Standby mode
Figure 2-11 CPU Operation States