Datasheet

Table Of Contents
Section 6 Power-Down Modes
Rev. 2.00 Jul. 04, 2007 Page 118 of 692
REJ09B0309-0200
6.2.5 Subactive Mode
In subactive mode, the system clock oscillator and the on-chip oscillator for the system clock stop
functioning but on-chip peripheral modules other than the A/D converter, PWM, TPU, and IIC2
continue to operate. As long as a required voltage is applied, the contents of some registers of the
on-chip peripheral modules are retained.
Subactive mode is cleared by the SLEEP instruction. When subacitve mode is cleared, a transition
to subsleep mode, active mode, or watch mode is made, depending on the combination of bits
SSBY, LSON, and TMA3 in SYSCR1 and bits MSON and DTON in SYSCR2.
When a reset source is generated in subactive mode, the system clock oscillator starts. The RES
pin must be kept low until the system clock oscillator output stabilizes and the t
REL
period has
elapsed. The CPU starts reset exception handling when the RES pin is driven high.
The operating frequency of subactive mode is selected from φ
W
/2, φ
W
/4, and φ
W
/8 by the SA1 and
SA0 bits in SYSCR2. After the SLEEP instruction is executed, the operating frequency changes to
the frequency which is set before the execution.
6.2.6 Active (Medium-Speed) Mode
In active (medium-speed) mode, the clock set by the MA1 and MA0 bits in SYSCR1 is used as the
system clock, and the CPU and on-chip peripheral modules function.
Active (medium-speed) mode is cleared by the SLEEP instruction. When active (medium-speed)
mode is cleared, a transition to standby mode is made depending on the combination of bits
SSBY, LSON, and TMA3 in SYSCR1, a transition to watch mode is made depending on the
combination of bits SSBY and TMA3 in SYSCR1, or a transition to sleep mode is made
depending on the combination of bits SSBY and LSON in SYSCR1. Moreover, a transition to
active (high-speed) mode or subactive mode is made by a direct transition. When a reset source is
generated in active (medium-speed) mode, the CPU goes into the reset state and active (medium-
sleep) mode is cleared.