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Mode
Instruction
Entry mode
Wake-up mode
Voltage
regulator
Effect on
1.5V area
clock
Effect on
V
DD
area
clock
Standby
1.5V power off
PDDSCFG bit
+SLEEPDEEP
bit +WFI or WFE
Rising edge of
WKUP pin, RTC
alarm event,
external reset on
NRST pin, IWDT
reset
Off
HSECLK
is turned
off
Sleep mode
The characteristics of sleep mode are shown in the table below
Table 23 Characteristics of Sleep Mode
Characteristics
Instruction
Enter
Enter the sleep mode immediately by executing WFI or WFE instructions;
When SLEEPONEXIT is set to 0 and WFI or WFE instruction is executed, the system
will enter the sleep mode immediately; when SLEEPONEXIT is set to 1, the system
will exit the interrupt program and then enter the sleep mode immediately.
Wake-up
If WFI instruction is executed to enter the sleep mode, wake up by any interrupt; If
WFE instruction is executed to enter the sleep mode, wake up through an event.
Sleep
The core stops working, all peripherals are still running, and the data in the core
registers and memory before sleep are saved.
Wake-up delay
None
After wake-up
If the system is woken up by interrupt, it will first enter the interrupt, then exit the
interrupt, and then execute the program after WFI instruction. If the system is woken
up by event, it will directly execute the program after WFE instruction.
Stop mode
The characteristics of stop mode are shown in the table below:
Table 24 Characteristics of Stop Mode
Characteristics
Instruction
Enter
SLEEPDEEP bit of the core register is set to 1, PDDSCFG bit of the register
PMU_CTRL is set to 0, and when executing WFI or WFE instruction, the system will
enter the stop mode immediately;
When LPDSCFG bit of the register PMU_CTRL is set to 0, the voltage regulator is
working in normal mode; when LPDSCFG bit of the register PMU_CTRL is set to 1,
the voltage regulator is working in low-power mode.
Wake-up
If WFI instruction is executed to enter the sleep mode, wake up by any interrupt; If
WFE instruction is executed to enter the sleep mode, wake up through an event.
Stop
The core will stop working, the peripheral will stop working, and the data in the core
register and memory before stop will be saved.
Wake-up delay
HSICLK oscillator wake-up time + voltage regulator wake-up time from low-power
mode.
After wake-up
If the system is woken up by interrupt, it will first enter the interrupt, then exit the
interrupt, and then execute the program after WFI instruction. If the system is woken
up by event, it will directly execute the program after WFE instruction.
Standby mode
The characteristics of standby mode are shown in the table below:
