Table 26. Stop 2 Mode - ST STM32L4x6 Reference Manual

Power control (PWR)
When exiting Stop 2 mode by issuing an interrupt or a wakeup event, the HSI16 oscillator is
selected as system clock if the bit STOPWUCK is set in
(RCC_CFGR). The MSI oscillator is selected as system clock if the bit STOPWUCK is
cleared. The wakeup time is shorter when HSI16 is selected as wakeup system clock. The
MSI selection allows wakeup at higher frequency, up to 48 MHz.
When exiting the Stop 2 mode, the MCU is in Run mode (Range 1 or Range 2 depending on
VOS bit in PWR_CR1).
Stop 2 mode
Mode entry
Mode exit
Wakeup latency
156/1693

Table 26. Stop 2 mode

WFI (Wait for Interrupt) or WFE (Wait for Event) while:
– SLEEPDEEP bit is set in Cortex
– No interrupt (for WFI) or event (for WFE) is pending
– LPMS = "010" in PWR_CR1
On return from ISR while:
– SLEEPDEEP bit is set in Cortex
– SLEEPONEXIT = 1
– No interrupt is pending
– LPMS = "010" in PWR_CR1
Note: To enter Stop 2 mode, all EXTI Line pending bits (in
register 1 (EXTI_PR1)), and the peripheral flags generating wakeup
interrupts must be cleared. Otherwise, the Stop mode entry
procedure is ignored and program execution continues.
If WFI or Return from ISR was used for entry:
Any EXTI Line configured in Interrupt mode (the corresponding EXTI
Interrupt vector must be enabled in the NVIC). The interrupt source can
be external interrupts or peripherals with wakeup capability. Refer to
Table 42: STM32L4x6 vector
If WFE was used for entry and SEVONPEND = 0:
Any EXTI Line configured in event mode. Refer to
Wakeup event management.
If WFE was used for entry and SEVONPEND = 1:
Any EXTI Line configured in Interrupt mode (even if the corresponding
EXTI Interrupt vector is disabled in the NVIC). The interrupt source can
be external interrupts or peripherals with wakeup capability. Refer to
Table 42: STM32L4x6 vector
Any EXTI Line configured in event mode. Refer to
Wakeup event management.
Longest wakeup time between: MSI or HSI16 wakeup time and regulator
wakeup time from Low-power mode + Flash wakeup time from Stop 2
mode.
DocID024597 Rev 3
Clock configuration register
Description
®
-M4 System Control register
®
-M4 System Control register
table.
Section 12.3.2:
table.
Section 12.3.2:
RM0351
Pending