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CHAPTER 25 STAND-BY FUNCTION
(b) Releasing the IDLE mode
(i) Releasing the IDLE mode by NMI input
When the valid edge set in the external interrupt edge enable registers (EGP0, EGN0) is input to the
NMI input, the IDLE mode is released.
When the IDLE mode is released and nonmaskable interrupts by the NMI pin input can be accepted,
execution branches to the NMI interrupt service program. When interrupts cannot be accepted (when
set to the IDLE mode in the NMI interrupt service program), execution restarts from the instruction
following the instruction that set the IDLE mode. When interrupts can be accepted (by executing the
RETI instruction), execution branches to the NMI interrupt service program.
For details about accepting NMI interrupts, refer to
23.6 Nonmaskable Interrupt Acceptance
.
(ii) Releasing IDLE mode by INTP0 to INTP6 inputs, watch timer interrupt, and key return interrupt
If interrupt masking is released through INTP0 to INTP6 input and macro service is disabled, the oscillator
restarts oscillating when a valid edge specified in the external interrupt edge enable registers (EGP0,
EGPN0) is input to INTP0 to INTP6. If the mask of watch timer interrupt is released and macro service
is disabled, an overflow of watch timer occurs and IDLE mode is released. If key return interrupt masking
is released and macro service is disabled, the oscillator restarts oscillating when a falling edge is input
to the port 8 pins (P80 to P87).
When the IDLE mode is released and the interrupt enable flag (IE) is set to one, if interrupts can be
accepted, execution branches to interrupt service program. When interrupts cannot be accepted and
when the IE flag is cleared to zero, execution restarts from the instruction following the instruction that
set the IDLE mode.
For details about interrupt acceptance, refer to
23.7 Maskable Interrupt Acceptance
.
(iii) Releasing the IDLE mode by RESET input
When RESET input falls from high to low and the reset condition is entered, the oscillator starts
oscillating. Maintain the oscillation stable time for the RESET active period. Then when RESET rises,
normal operation starts.
The difference from the normal reset operation is the data memory saves the contents before setting
the IDLE mode.