RM0440 Rev 4 245/2126
RM0440 Power control (PWR)
271
by:
– NVIC IRQ interrupt.
- When SEVONPEND = 0 in the Cortex
®
-M4 with FPU System Control register. By
enabling an interrupt in the peripheral control register and in the NVIC. When the
MCU resumes from WFE, the peripheral interrupt pending bit and the NVIC
peripheral IRQ channel pending bit (in the NVIC interrupt clear pending register)
have to be cleared.
Only NVIC interrupts with sufficient priority wakeup and interrupt the MCU.
- When SEVONPEND = 1 in the Cortex
®
-M4 with FPU System Control register.
By enabling an interrupt in the peripheral control register and optionally in the
NVIC. When the MCU resumes from WFE, the peripheral interrupt pending bit and
when enabled the NVIC peripheral IRQ channel pending bit (in the NVIC interrupt
clear pending register) have to be cleared.
All NVIC interrupts wakeup the MCU, even the disabled ones. Only enabled NVIC
interrupts with sufficient priority wakeup and interrupt the MCU.
–Event
Configuring a EXTI line in event mode. When the CPU resumes from WFE, it is
not necessary to clear the EXTI peripheral interrupt pending bit or the NVIC IRQ
channel pending bit as the pending bits corresponding to the event line is not set.
It may be necessary to clear the interrupt flag in the peripheral.
From Standby modes, and Shutdown modes the MCU exit low power mode through an
external reset (NRST pin), an IWDG reset, a rising edge on one of the enabled WKUPx pins
or a RTC event occurs (see Figure 528: RTC block diagrams).
After waking up from Standby or Shutdown mode, program execution restarts in the same
way as after a Reset (boot pin sampling, option bytes loading, reset vector is fetched, etc.).
6.3.4 Sleep mode
I/O states in Sleep mode
In Sleep mode, all I/O pins keep the same state as in Run mode.
Entering the Sleep mode
The Sleep mode is entered according Section : Entering low power mode, when the
SLEEPDEEP bit in the Cortex
®
-M4 with FPU System Control register is clear.
Refer to Table 43: Sleep for details on how to enter the Sleep mode.
Exiting the Sleep mode
The Sleep mode is exit according Section : Exiting low power mode.
Refer to Table 43: Sleep for more details on how to exit the Sleep mode.
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