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CHAPTER 24 STANDBY FUNCTION
User’s Manual U12697EJ3V0UM
(b) Releasing the IDLE mode
(i) Releasing the IDLE mode by NMI input
When the valid edge set in external interrupt edge enable registers 0 (EGP0, EGN0) is input to the NMI
input, the IDLE mode is released.
When the IDLE mode is released and non-maskable interrupts by the NMI pin input can be acknowledged,
execution branches to the NMI interrupt service program. When interrupts cannot be acknowledged
(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 acknowledged (by executing
the RETI instruction), execution branches to the NMI interrupt service program.
For details about NMI interrupt acknowledgement, refer to
22.6 Non-Maskable Interrupt Acknowledgment
Operation
.
(ii) Releasing IDLE mode by INTP0 to INTP5 inputs and watch timer interrupt
If interrupt masking is released through INTP0 to INTP5 input and macro service is disabled, the oscillator
restarts oscillating when a valid edge specified in external interrupt edge enable registers 0 (EGP0,
EGN0) is input to INTP0 to INTP5. 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.
When the IDLE mode is released and the interrupt enable flag (IE) is set to 1, if interrupts can be accepted,
execution branches to interrupt service program. When interrupts cannot be acknowledged and when
the IE flag is cleared to 0, execution restarts from the instruction following the instruction that set the
IDLE mode.
For details about interrupt acknowledgement, refer to
22.7 Maskable Interrupt Acknowledgment
Operation
.
(iii) 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.
