Panasonic MN101L Series User Manual page 162

Chapter 4
Clock/ Mode/ Voltage Control
Transition to HALT Mode
The system can change from any mode of NORMAL and SLOW to HALT0/HALT1/HALT2/HALT3 mode.
In HALT0/HALT1 mode, CPU is stopped operating while the oscillators remain active. In HALT2/HALT3
mode, only the low-speed oscillator remains active and the clock is supplied only to Real time clock.
CPU wakes up from HALT mode by interrupt or reset. When resetting, the normal reset operation is executed.
When an interrupt occurs, the mode is returned to the same status as before changing to HALT mode.
The transition procedure from CPU operating mode to HALT mode is shown below.
• Transition procedure from NORMAL mode to HALT0 mode
Set CPUM.HALT to "1".
• Transition procedure from NORMAL mode to HALT2 mode
Set CPUM.HALT to "1" and CPUM.OSCMOD to "0" at the same time while the low-speed oscillation is sta-
ble.
• Transition procedure from SLOW mode to HALT1/HALT3 mode
Set CPUM.HALT to "1". If CPUM.HALTMOD is "0"and "1", the mode changes to HALT1 and HALT3,
respectively.
• Transition procedure from NORMAL mode to HALT1/HALT3 mode
Set CPUM.HALT to "1", CPUM.OSCMOD to "0", and CPUM.CLKSEL to "0" at the same time while the
low-speed oscillation is stable. If CPUM.HALTMOD is "0", and "1", the mode changes to HALT1 and
HALT3, respectively.
• The transition procedure from SLOW mode to HALT0 mode
Set CPUM.HALT to "1", CPUM.OSCMOD to "1", and CPUM.CLKSEL to "1" at the same time.
• The transition procedure from SLOW mode to HALT2 mode
Set CPUM.HALT to "1", CPUM.OSCMOD to "0", and CPUM.CLKSEL to "1" at the same time.
Figure:4.2.10 and Figure:4.2.11 show the transition procedure from CPU operating mode to HALT mode.
Figure:4.2.10 Transition from CPU Operating Mode to HALT0/HALT1/HALT2 Mode
IV - 20 Mode Control Function
NORMAL/SLOW mode
Transition to HALT0/HALT1/HALT2 mode
(Set the CPUM as described in Table 4.1.3.)
HALT mode