Chapter 4
Clock/ Mode/ Voltage Control
IV - 22 Mode Control Function
Transition to STOP Mode
The system changes from any mode of NORMAL and SLOW to STOP0/STOP1 mode. In any case, both oscilla-
tion and CPU are stopped. A reset or an interrupt is a source for wake up from STOP mode.
Figure:4.2.12 shows the transition procedure from CPU operating mode to STOP mode.
In STOP mode, the value of the WDT counter is cleared. After waking up from STOP mode, oscillation stabiliza-
tion wait time is inserted and the timer starts counting.
• Transition procedure from NORMAL mode to STOP0 mode
Set CPUM.STOP to "1".
• Transition procedure from SLOW mode to STOP1 mode
Set CPUM.STOP to "1".
• Transition procedure from NORMAL mode to STOP1 mode
Set CPUM.STOP to "1", CPUM.OSCMOD to "0", and CPUM.CLKSEL to "0" at the same time while the
low-speed oscillation is stable.
• Transition procedure from SLOW mode to STOP0 mode
Set CPUM.STOP to "1", CPUM.OSCMOD to "1", and CPUM.CLKSEL to "1" at the same time.
Figure:4.2.12 Transition Flow from CPU Operating Mode to STOP Mode
..
If the value of xICR.LV1-0 for an interrupt to be used as a return factor is equal or larger than
the value of PSW.IM1-0 before transition to STANDBY mode, it is impossible to return to
CPU operating mode by a maskable interrupt.
..
Transition to STOP0/STOP1 mode
(Set the CPUM as described in Table 4.1.3.
NORMAL/SLOW mode
STOP0/STOP1 mode
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