HD64F3337YCP16V Datasheet, PDF (571/749 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 22 Power-Down State
22.1 Overview
The H8/3337 Series and H8/3397 Series have a power-down state that greatly reduces power
consumption by stopping some or all of the chip functions. The power-down state includes three
modes:
1. Sleep mode
2. Software standby mode
3. Hardware standby mode
Table 22.1 lists the conditions for entering and leaving the power-down modes. It also indicates
the status of the CPU, on-chip supporting modules, etc. in each power-down mode.
Table 22.1 Power-Down State
Mode
Sleep
mode
Entering
Procedure
Execute
SLEEP
instruction
State
CPU Sup.
Clock CPU Reg’s. Mod.
Active Halted Held
Active
I/O
RAM Ports
Held Held
Software
standby
mode
Set SSBY bit
in SYSCR to
1, then
execute
SLEEP
instruction
Halted Halted Held
Halted Held Held
and
initialized
Hardware Set STBY
standby pin to low
mode
level
Halted Halted Undeter- Halted Held
mined and
initialized
Note: SYSCR: System control register
SSBY: Software standby bit
High
impe-
dance
state
Exiting
Methods
• Interrupt
• RES
• STBY
• NMI
• IRQ₀–IRQ₂
IRQ₆ (incl.
KEYIN₀–
KEYIN₇)
• RES
• STBY
• STBY and
RES
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