Standby Mode; Table 29. Stop Mode Entry And Exit (Stm32F42Xxx And Stm32F43Xxx) - ST STM32F405 Reference Manual

Power controller (PWR)

Table 29. Stop mode entry and exit (STM32F42xxx and STM32F43xxx)

Stop mode
Mode entry
Mode exit
Wakeup latency
5.3.6

Standby mode

The Standby mode allows to achieve the lowest power consumption. It is based on the
®
Cortex -M4 with FPU deepsleep mode, with the voltage regulator disabled. The 1.2 V
domain is consequently powered off. The PLLs, the HSI oscillator and the HSE oscillator are
also switched off. SRAM and register contents are lost except for registers in the backup
domain (RTC registers, RTC backup register and backup SRAM), and Standby circuitry (see
Figure 9).
136/1749
WFI (Wait for Interrupt) or WFE (Wait for Event) while:
– No interrupt or event is pending,
– SLEEPDEEP bit is set in Cortex
– PDDS bit is cleared in Power Control register (PWR_CR),
– Select the voltage regulator mode by configuring LPDS, MRUDS, LPUDS
and UDEN bits in PWR_CR (see
(STM32F42xxx and STM32F43xxx)).
On Return from ISR while:
– No interrupt is pending,
– SLEEPDEEP bit is set in Cortex
and
– SLEEPONEXIT = 1, and
– PDDS is cleared in PWR_CR1.
Note: To enter Stop mode, all EXTI Line pending bits (in
(EXTI_PR)), all peripheral interrupts pending bits, the RTC Alarm
(Alarm A and Alarm B), RTC wakeup, RTC tamper, and RTC time
stamp flags, must be reset. Otherwise, the Stop mode entry
procedure is ignored and program execution continues.
If WFI or Return from ISR was used for entry:
All EXTI lines 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 61: Vector table for STM32F405xx/07xx and STM32F415xx/17xx
on page 372.
If WFE was used for entry and SEVONPEND = 0:
All EXTI Lines configured in event mode. Refer to
Wakeup event management on page 380
If WFE was used for entry and SEVONPEND = 1:
– Any EXTI lines 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 61: Vector table for STM32F405xx/07xx and STM32F415xx/17xx
on page 372 and Table 62: Vector table for STM32F42xxx and
STM32F43xxx.
– Wakeup event: refer to
page 380.
Refer to Table 28: Stop operating modes (STM32F42xxx and
STM32F43xxx)
RM0090 Rev 18
Description
®
-M4 with FPU System Control register,
Table 28: Stop operating modes
®
-M4 with FPU System Control register,
Section 12.2.3: Wakeup event management on
RM0090
Pending register
Section 12.2.3: