Exit From Software Standby Mode - Renesas RX100 Series User Manual

RX13T Group
11.6.3.2

Exit from Software Standby Mode

Exit from software standby mode is initiated by an external pin interrupt (the NMI or IRQ0 to IRQ5), peripheral function
interrupts (the IWDT, and voltage monitoring), a RES# pin reset, a power-on reset, a voltage monitoring reset, or an
independent watchdog timer reset. When any trigger which initiates exit from software standby mode is asserted, the
oscillators which were operating before entry to software standby mode restart operation. After the oscillation of all these
oscillators has been stabilized, operation returns from software standby mode.
 Initiated by an interrupt
When an interrupt request from among the NMI, IRQ0 to IRQ5, IWDT, voltage monitoring interrupts is generated,
each of the oscillators which was operating before the transition to software standby mode resumes oscillation.
After the oscillation stabilization wait time of each oscillator set by the MOSCWTCR.MSTS[4:0] bits has elapsed,
the MCU exits software standby mode and interrupt exception processing starts.
 Initiated by a RES# pin reset
Clock oscillation starts when the low level is applied to the RES# pin. Clock supply for the MCU starts at the same
time. Keep the level on the RES# pin low over the time required for oscillation of the clocks to become stable. Reset
exception processing starts when the high level is applied to the RES# pin.
 Initiated by a power-on reset
A power-on reset asserts a reset to the MCU.
When a power-on reset is negated by a rise in the supply voltage, the CPU starts the reset exception handling.
 Initiated by a voltage monitoring reset
A voltage monitoring reset asserts a reset to the MCU.
When a voltage monitoring reset is negated by a rise in the supply voltage, the CPU starts the reset exception
handling.
 Initiated by an independent watchdog timer reset
An internal reset generated by an IWDT underflow asserts a reset to the MCU.
Note that the independent watchdog timer is stopped in software standby mode due to the register settings
(OFS0.IWDTSTRT = 0 and OFS0.IWDTSLCSTP = 1, or OFS0.IWDTSTRT = 1 and IWDTCSTPR.SLCSTP = 1)
in software standby mode. In that case, exit from software standby mode by the independent watchdog timer reset
cannot be done.
R01UH0822EJ0100 Rev.1.00
Jul 31, 2019
11. Low Power Consumption
Page 184 of 1041