HD64F38602R Datasheet, PDF (66/552 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer

Section 2 CPU
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 5, Power-Down Modes. For details on exception handling, refer
to section 3, Exception Handling.
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
reduce power consumption
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
Figure 2.11 CPU Operating States
Rev. 3.00 May 15, 2007 Page 34 of 516
REJ09B0152-0300