HD64F3670 Datasheet, PDF (93/305 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

6.2 Mode Transitions and States of the 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 the 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
Program halt state
Standby mode
Program execution state
SLEEP
instruction
Interrupt
Active mode
Direct transition
interrupt
SLEEP
instruction
Interrupt
SLEEP
instruction
Program halt state
Sleep mode
Interrupt
Subsleep mode
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.
Figure 6-1 Mode Transition Diagram
Rev. 1.0, 03/01, page 69 of 280