HD64F36024FX Datasheet, PDF (65/386 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

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 mode. In the program halt
state there are a sleep mode, and standby 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
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
Program halt state
A state in which some
or all of the chip
functions are stopped
to conserve power
The CPU executes
successive program
instructions at reduced
speed, synchronized
by the subclock
Sleep mode
Standby mode
Power-down
modes
Exception-
handling state
A transient state in which the CPU changes
the processing flow due to a reset or an interrupt
Figure 2.11 CPU Operation States
Rev. 4.00 Sep. 23, 2005 Page 37 of 354
REJ09B0025-0400