
Section 21 Power-Down Modes
Rev. 1.00 Mar. 02, 2006 Page 693 of 798
REJ09B0255-0100
21.2
Mode Transitions and LSI States
Figure 21.1 shows the possible mode transition diagram. The mode transition from program
execution state to program halt state is performed by the SLEEP instruction. The mode transition
from program halt state to program execution state is performed by an interrupt. The
RES input
causes a mode transition from any state to the reset state. Table 21.2 shows the LSI internal states
in each operating mode.
Interrupt*2
Subsleep mode
(subclock)
Program halt state
Program execution state
RES pin = Low
RES pin = High
Reset state
SLEEP instruction
External interrupt*3
Any interrupt
SLEEP
instruction
Interrupt*1
LSON bit = 0
SSBY = 0, LSON = 0
SSBY = 1,
PSS = 0, LSON = 0
SSBY = 1,
PSS = 1, DTON = 0
High-speed
mode
(main clock)
Software
standby mode
Sleep mode
(main clock)
Watch mode
(subclock)
SLEEP instruction
SLEEP
instruction
SSBY = 0,
PSS = 1, LSON = 1
Interrupt*1
LSON bit = 1
SLEEP instruction
: Power-down mode
SLEEP instruction
SSBY = 1, PSS = 1,
DTON = 1, LSON = 1
Clock switching
exception processing
SLEEP instruction
SSBY = 1, PSS = 1,
DTON = 1, LSON = 0
After the oscillation
stabilization time
(STS2 to STS0), clock
switching exception
processing
Subactive mode
(subclock)
: Transition after exception processing
Notes: When a transition is made between modes by means of an interrupt, the transition cannot be made
on interrupt source generation alone. Ensure that interrupt handling is performed after accepting the
interrupt request.
1.
2.
3.
NMI, IRQ0 to IRQ15, KIN0 to KIN15, WUE8 to WUE15, WDT_1, and PS2 interrupts
NMI, IRQ0 to IRQ15, KIN0 to KIN15, WUE8 to WUE15, WDT_0, WDT_1, TMR_0, TMR_1,
and PS2 interrupts
NMI, IRQ0 to IRQ15, KIN0 to KIN15, WUE8 to WUE15, and PS2 interrupts
Figure 21.1 Mode Transition Diagram