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CHAPTER 24 STANDBY FUNCTION
User’s Manual U12697EJ3V0UM
(1) Releasing the IDLE mode by NMI input
When the valid edge specified in external interrupt edge enable registers 0 (EGP0, EGN0) is input by the NMI
input, the IDLE mode is released.
When the IDLE mode is released and the non-maskable interrupt from the NMI pin input can be acknowledged,
execution branches to the NMI interrupt service program. If acknowledgement is not possible (such as when
set in the IDLE mode in the NMI interrupt service program), execution starts again from the instruction following
the instruction that set the IDLE mode. When acknowledgement is enabled, execution branches to the NMI
interrupt service program (by executing the RETI instruction).
For details about NMI interrupt acknowledgement, refer to
22.6 Non-Maskable Interrupt Acknowledgment
Operation
.
(2) Releasing the IDLE mode by INTP0 to INTP5 input and watch timer interrupt
If interrupt masking by INTP0 to INTP5 input is canceled and macro service is prohibited and the valid edge
specified with external interrupt edge enable register 0 (EGP0, EGN0) is input to INTP0 to INTP5, the IDLE mode
is canceled. At the same time, an overflow will occur with the watch timer and the IDLE mode will be released
when the watch timer interrupt mask is released and macro services are prohibited.
If interrupts can be acknowledged when released from the IDLE mode and the interrupt enable flag (IE) is set
to one, execution branches to the interrupt service program. If the IE flag is cleared to 0 when acknowledgement
is not possible, execution starts again from the instruction following the instruction that set the IDLE mode.
For details on interrupt acknowledgement, refer to
22.7 Maskable Interrupt Acknowledgment Operation
.
(3) Releasing the IDLE mode by RESET input
When RESET input rises from low to high and the reset condition is released, the oscillator starts oscillating.
Oscillation stops for the RESET active period. After the oscillation stabilization time elapses, normal operation
starts.
The difference from the normal reset operation is the data memory saves the contents before setting the IDLE
mode.
