Mode Transitions And Lsi States; Figure 20.1 Mode Transition Diagram - Renesas H8S/2111B Hardware Manual

20.2

Mode Transitions and LSI States

Figure 20.1 shows the enabled 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 STBY input
causes a mode transition from any state to hardware standby mode. The RES input causes a mode
transition from a state other than hardware standby mode to the reset state. Table 20.2 shows the
LSI internal states in each operating mode.
Program execution state
SCK2 to
SCK0 are
0
SLEEP instruction
SSBY = 1, PSS = 1,
DTON = 1, LSON = 0
After the oscillation
stabilization time
(STS2 to STS0), clock
switching exception
handling
Notes: 1.
NMI, IRQ0 to IRQ2, IRQ6, IRQ7, and WDT1 interrupts
2. NMI, IRQ0 to IRQ7, WDT0, WDT1, TMR0, and TMR1 interrupts
3. NMI, IRQ0 to IRQ2, IRQ6, and IRQ7 interrupts
• 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.
• Always select high-speed mode before making a transition to watch mode or sub-active mode.
Rev. 1.00, 05/04, page 468 of 544
Reset state
RES pin = High
High-speed mode
(main clock)
SCK2 to
SCK0 are
not 0
Medium-speed
mode
(main clock)
SLEEP instruction
SSBY = 1, PSS = 1,
DTON = 1, LSON = 1
Clock switching
exception handling
Subactive mode
(subclock)
: Transition after exception processing

Figure 20.1 Mode Transition Diagram

STBY pin = High
RES pin = Low
SLEEP instruction
Any interrupt
SLEEP
instruction
External
3
interrupt *
SLEEP
instruction
1
Interrupt *
LSON bit = 0
SLEEP
instruction
1
Interrupt *
LSON bit = 1
SLEEP instruction
2
Interrupt *
Program halt state
STBY pin = Low
Hardware
standby mode
SSBY = 0, LSON = 0
Sleep mode
(main clock)
SSBY = 1,
PSS = 0, LSON = 0
Software
standby mode
SSBY = 1,
PSS = 1, DTON = 0
Watch mode
(subclock)
SSBY = 0,
PSS = 1, LSON = 1
Subsleep mode
(subclock)
: Power-down mode