HD6473847RHV Datasheet, PDF (95/546 Pages) Renesas Technology Corp – Renesas 8-Bit Single-Chip Microcomputer H8 Family / H8/300L Super Low Power Series

Section 2 CPU
2.8 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. In the program halt state, there are a sleep (high-speed or
medium-speed) mode, standby mode, watch mode, and sub-sleep mode.
These states are shown in figure 2.15. Figure 2.16 shows the state transitions.
CPU state
Reset state
The CPU is initialized
Program execution state
Active (high-speed) mode
The CPU executes successive program
instructions at high speed,
synchronized by the system clock
Active (medium-speed) mode
The CPU executes successive
program instructions at
reduced speed, synchronized
by the system clock
Subactive mode
The CPU executes successive
program instructions at reduced
speed, synchronized by the subclock
Program halt state
A state in which the CPU
operation is stopped to
conserve power
Sleep (high-speed) mode
Sleep (medium-speed) mode
Standby mode
Watch mode
Exception-handling state
Subsleep mode
A transient state in which the CPU changes
the processing flow due to a reset or an interrupt
Note: See section 5, Power-Down Modes, for details on the modes and their transitions.
Figure 2.15 CPU Operation States
Rev. 7.00 Mar. 08, 2010 Page 63 of 510
REJ09B0024-0700