Renesas H8 Series Hardware Manual

Section 5 Power-Down Modes
Rev. 7.00 Mar 10, 2005 page 119 of 652
REJ09B0042-0700
Section 5 Power-Down Modes
5.1 Overview
The LSI has nine modes of operation after a reset. These include eight power-down modes, in
which power dissipation is significantly reduced. Table 5.1 gives a summary of the nine operating
modes.
Table 5.1 Operating Modes
Operating Mode Description
Active (high-speed) mode The CPU and all on-chip peripheral functions are operable on
the system clock in high-speed operation
Active (medium-speed) mode
The CPU and all on-chip peripheral functions are operable on
the system clock in low-speed operation
Subactive mode
The CPU and all on-chip peripheral functions are operable on
the subclock in low-speed operation
Sleep (high-speed) mode The CPU halts. On-chip peripheral functions are operable on
the system clock
Sleep (medium-speed) mode The CPU halts. On-chip peripheral functions operate at a
frequency of 1/128, 1/64, 1/32, or 1/16 of the system clock
frequency
Subsleep mode The CPU halts. The time-base function of timer A, timer C,
timer F, timer G, SCI3, AEC, and LCD controller/driver are
operable on the subclock
Watch mode The CPU halts. The time-base function of timer A, timer F,
timer G, AEC and LCD controller/driver are operable on the
subclock
Standby mode The CPU and all on-chip peripheral functions halt
Module standby mode Individual on-chip peripheral functions specified by software
enter standby mode and halt
Of these nine operating modes, all but the active (high-speed) mode are power-down modes. In
this section the two active modes (high-speed and medium speed) will be referred to collectively
as active mode.
Figure 5.1 shows the transitions among these operation modes. Table 5.2 indicates the internal
states in each mode.

Renesas H8 Series Specifications

General

Brand	Renesas
Model	H8 Series
Category	Computer Hardware
Language	English