Datasheet

Section 6 Power-Down Modes
Rev. 6.00 Mar. 24, 2006 Page 88 of 412
REJ09B0142-0600
6.2 Mode Transitions and States of LSI
Figure 6.1 shows the possible transitions among these operating modes. A transition is made from
the program execution state to the program halt state of the program by executing a SLEEP
instruction. Interrupts allow for returning from the program halt state to the program execution
state of the program. A direct transition between active mode and subactive mode, which are both
program execution states, can be made without halting the program. The operating frequency can
also be changed in the same modes by making a transition directly from active mode to active
mode, and from subactive mode to subactive mode. RES input enables transitions from a mode to
the reset state. Table 6.2 shows the transition conditions of each mode after the SLEEP instruction
is executed and a mode to return by an interrupt. Table 6.3 shows the internal states of the LSI in
each mode.
Reset state
Standby mode
Active mode
Sleep mode
Subsleep mode
Subactive
mode
Program halt state Program execution state Program halt state
SLEEP
instruction
SLEEP
instruction
Interrupt
Direct transition
interrupt
Direct transition
interrupt
Notes: 1. To make a transition to another mode by an interrupt, make sure interrupt handling is after the interrupt
is accepted.
2. Details on the mode transition conditions are given in table 6.2.
SLEEP
instruction
Direct
transition
interrupt
Direct
transition
interrupt
Interrupt
SLEEP
instruction
Interrupt
Interrupt
SLEEP
instruction
Interrupt
SLEEP
instruction
Figure 6.1 Mode Transition Diagram