H838024 datasheet(179/697 Pages) RENESAS

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Section 5 Power-Down Modes

Rev. 7.00 Mar 10, 2005 page 137 of 652

REJ09B0042-0700

5.8

Direct Transfer

5.8.1

Overview of Direct Transfer

The CPU can execute programs in three modes: active (high-speed) mode, active (medium-speed)

mode, and subactive mode. A direct transfer is a transition among these three modes without the

stopping of program execution. A direct transfer can be made by executing a SLEEP instruction

while the DTON bit in SYSCR2 is set to 1. After the mode transition, direct transfer interrupt

exception handling starts.

If the direct transfer interrupt is disabled in interrupt enable register 2 (IENR2), a transition is

made instead to sleep mode or watch mode. Note that if a direct transition is attempted while the I

bit in CCR is set to 1, sleep mode or watch mode will be entered, and it will be impossible to clear

the resulting mode by means of an interrupt.

• Direct transfer from active (high-speed) mode to active (medium-speed) mode

When a SLEEP instruction is executed in active (high-speed) mode while the SSBY and

LSON bits in SYSCR1 are cleared to 0, the MSON bit in SYSCR2 is set to 1, and the DTON

bit in SYSCR2 is set to 1, a transition is made to active (medium-speed) mode via sleep mode.

• Direct transfer from active (medium-speed) mode to active (high-speed) mode

When a SLEEP instruction is executed in active (medium-speed) mode while the SSBY and

LSON bits in SYSCR1 are cleared to 0, the MSON bit in SYSCR2 is cleared to 0, and the

DTON bit in SYSCR2 is set to 1, a transition is made to active (high-speed) mode via sleep

mode.

• Direct transfer from active (high-speed) mode to subactive mode

When a SLEEP instruction is executed in active (high-speed) mode while the SSBY and

LSON bits in SYSCR1 are set to 1, the DTON bit in SYSCR2 is set to 1, and the TMA3 bit in

TMA is set to 1, a transition is made to subactive mode via watch mode.

• Direct transfer from subactive mode to active (high-speed) mode

When a SLEEP instruction is executed in subactive mode while the SSBY bit in SYSCR1 is

set to 1, the LSON bit in SYSCR1 is cleared to 0, the MSON bit in SYSCR2 is cleared to 0,

the DTON bit in SYSCR2 is set to 1, and the TMA3 bit in TMA is set to 1, a transition is made

directly to active (high-speed) mode via watch mode after the waiting time set in SYSCR1 bits

STS2 to STS0 has elapsed.

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