Datasheet

Section 6 Power-Down Modes
Rev. 2.00 Sep. 23, 2005 Page 75 of 444
REJ09B0068-0200
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 from active mode to active mode changes the operating
frequency. 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
Sleep mode
Subsleep mode
Program halt state Program execution state Program halt state
SLEEP
instruction
SLEEP
instruction
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.
Interrupt
SLEEP
instruction
Interrupt
Active mode
Figure 6.1 Mode Transition Diagram
Table 6.2 Transition Mode after SLEEP Instruction Execution and Interrupt Handling
DTON SSBY SMSEL
Transition Mode after SLEEP
Instruction Execution
Transition Mode due to
Interrupt
0 0 0 Sleep mode Active mode
0 1 Subsleep mode Active mode
1 X Standby mode Active mode
1 X 0* Active mode (direct transition)
[Legend]
X: Don't care.