Power controller (PWR)
RM0090
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DocID018909 Rev 11
Entering Stop mode (STM32F42xxx and STM32F43xxx)
The Stop mode is entered according to
Section : Entering low-power mode
, when the
SLEEPDEEP bit in the Cortex
®
-M4 with FPU System Control register is set.
for details on how to enter the Stop mode.
When the microcontroller enters in Stop mode, the voltage scale 3 is automatically selected.
To further reduce power consumption in Stop mode, the internal voltage regulator can be put
in low-power or low voltage mode. This is configured by the LPDS, MRUDS, LPUDS and
UDEN bits of the
PWR power control register (PWR_CR) for STM32F405xx/07xx and
.
If Flash memory programming is ongoing, the Stop mode entry is delayed until the memory
access is finished.
If an access to the APB domain is ongoing, The Stop mode entry is delayed until the APB
access is finished.
If the Over-drive mode was enabled before entering Stop mode, it is automatically disabled
during when the Stop mode is activated.
Table 28. Stop operating modes (STM32F42xxx and STM32F43xxx)
Voltage Regulator Mode
UDEN[1:0]
bits
MRUDS
bit
LPUDS
bit
LPDS
bit
FPDS
bit
Wakeup latency
Normal
mode
STOP MR
(Main Regulator)
-
0
-
0
0
HSI RC startup time
STOP MR- FPD
-
0
-
0
1
HSI RC startup time +
Flash wakeup time from power-
down mode
STOP LP
-
0
0
1
0
HSI RC startup time +
regulator wakeup time from LP
mode
STOP LP-FPD
-
-
0
1
1
HSI RC startup time +
Flash wakeup time from power-
down mode +
regulator wakeup time from LP
mode
Under-
drive
Mode
STOP UMR-
FPD
3
1
-
0
-
HSI RC startup time +
Flash wakeup time from power-
down mode +
Main regulator wakeup time from
under-drive mode + Core logic to
nominal mode
STOP ULP-FPD
3
-
1
1
-
HSI RC startup time +
Flash wakeup time from power-
down mode +
regulator wakeup time from LP
under-drive mode + Core logic to
nominal mode