Power controller (PWR)
RM0090
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Only enabled NVIC interrupts with sufficient priority will wakeup and interrupt the MCU.
5.3.1 Slowing
down system clocks
In Run mode the speed of the system clocks (SYSCLK, HCLK, PCLK1, PCLK2) can be
reduced by programming the prescaler registers. These prescalers can also be used to slow
down peripherals before entering Sleep mode.
For more details refer to
Section 7.3.3: RCC clock configuration register (RCC_CFGR)
.
5.3.2
Peripheral clock gating
In Run mode, the HCLKx and PCLKx for individual peripherals and memories can be
stopped at any time to reduce power consumption.
To further reduce power consumption in Sleep mode the peripheral clocks can be disabled
prior to executing the WFI or WFE instructions.
Table 23. Low-power mode summary
Mode name
Entry
Wakeup
Effect on 1.2 V
domain clocks
Effect on
V
DD
domain
clocks
Voltage regulator
Sleep
(Sleep now or
Sleep-on-
exit)
WFI or Return
from ISR
Any interrupt
CPU CLK OFF
no effect on other
clocks or analog
clock sources
None
ON
WFE
Wakeup event
Stop
PDDS and LPDS
bits +
SLEEPDEEP bit
+ WFI, Return
from ISR or WFE
Any EXTI line (configured
in the EXTI registers,
internal and external lines)
All 1.2 V domain
clocks OFF
HSI and
HSE
oscillator
s OFF
ON or in low- power
mode (depends on
PWR power control
register (PWR_CR)
and
Standby
PDDS bit +
SLEEPDEEP bit
+ WFI, Return
from ISR or WFE
WKUP pin rising edge,
RTC alarm (Alarm A or
Alarm B), RTC Wakeup
event, RTC tamper
events, RTC time stamp
event, external reset in
NRST pin, IWDG reset
OFF