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CHAPTER 17 STANDBY FUNCTION
User’s Manual U15017EJ2V0UD
(1) STOP mode release by INTP0 to INTP2 input
When masking of interrupts by INTP0 to INTP2 input is released and macro service is disabled, the oscillator
resumes oscillation when the valid edge specified by external interrupt mode register 1 (INTM1) is input to the
INTP0 to INTP2 input. Following this, the STOP mode is released after the oscillation stabilization time specified
by the oscillation stabilization time specification register (OSTS) elapses.
When the
μ
PD784975A is released from the STOP mode, if an interrupt can be acknowledged when the interrupt
enable flag (IE) is set (to 1), a branch is made to the interrupt service program. If the interrupt cannot be
acknowledged and if the IE flag is cleared (to 0), execution is resumed from the instruction following the instruction
that set the STOP mode. Refer to
16.7 Maskable Interrupt Acknowledgment Operation
for details of interrupt
acknowledgment.
Figure 17-6. STOP Mode Release by INTP0 to INTP2 Input
(2) STOP mode release by RESET input
When the RESET input goes from high to low, the reset state is established. The clock starts oscillating at the
rising edge of RESET. When the oscillation stabilization timer expires, the normal operation starts. At this point,
the internal data memory retains the contents prior to the STOP mode setting.
INTP0 to INTP2 input
Rising edge
specified
Oscillator
f
XX
/2
STP F/F1
STP F/F2
Oscillator stopped
STOP
Timer count time for
oscillation stabilization
Time until clock starts oscillating