Standby Mode; Table 26. Stop Mode - STMicroelectronics RM0365 Reference Manual

RM0365
Stop mode
Mode entry
Mode exit
Wakeup latency
8.3.5

Standby mode

The Standby mode allows to achieve the lowest power consumption. It is based on the
®
ARM Cortex
is consequently powered off. The PLL, the HSI oscillator and the HSE oscillator are also
switched off. SRAM and register contents are lost except for registers in the RTC domain
and Standby circuitry (see
Entering Standby mode
Refer to
In Standby mode, the following features can be selected by programming individual control
bits:
•
Independent watchdog (IWDG): the IWDG is started by writing to its Key register or by
hardware option. Once started it cannot be stopped except by a reset. See
WFI (Wait for Interrupt) or WFE (Wait for Event) while:
– Set SLEEPDEEP bit in ARM
– Clear PDDS bit in Power Control register (PWR_CR)
– Select the voltage regulator mode by configuring LPDS bit in PWR_CR
Note: To enter Stop mode, all EXTI Line pending bits (in
(EXTI_PR1)), all peripherals interrupt pending bits and RTC Alarm flag
must be reset. Otherwise, the Stop mode entry procedure is ignored and
program execution continues.
If the application needs to disable the external oscillator (external clock)
before entering Stop mode, the system clock source must be first switched
to HSI and then clear the HSEON bit.
Otherwise, if before entering Stop mode the HSEON bit is kept at 1, the
security system (CSS) feature must be enabled to detect any external
oscillator (external clock) failure and avoid a malfunction when entering
Stop mode.
If WFI was used for entry:
– Any EXTI Line configured in Interrupt mode (the corresponding EXTI
Interrupt vector must be enabled in the NVIC).
– Some specific communication peripherals (USART, I2C) interrupts, when
programmed in wakeup mode (the peripheral must be programmed in
wakeup mode and the corresponding interrupt vector must be enabled in
the NVIC).
Refer to
STM32F302x6/8 vector
If WFE was used for entry:
Any EXTI Line configured in event mode. Refer to
Wakeup event management on page 213
HSI RC wakeup time + regulator wakeup time from Low-power mode
®
-M4 deepsleep mode, with the voltage regulator disabled. The 1.8 V domain
Figure
Table 27 for more details on how to enter Standby mode.

Table 26. Stop mode

®
Table 40: STM32F302xB/C/D/E vector table
table.
8).
DocID025202 Rev 7
Power control (PWR)
Description
®
Cortex -M4 System Control register
and
Section 13.2.3:
Pending register
Table 41:
106/1080
112