Datasheet

Table Of Contents
Functional overview STM32WLE5J8/JB/JC
26/135 DS13105 Rev 4
The voltage regulators are always enabled after a reset. Depending on the application
modes, the V
CORE
supply is provided either by the main regulator or by the low-power
regulator (LPR).
When MR is used, a dynamic voltage scaling is proposed to optimize power as follows:
range 1: high-performance range
The system clock frequency can be up to 48 MHz. The Flash memory access time for
read access is minimum. Write and erase operations are possible.
range 2: low-power range
The system clock frequency can be up to 16 MHz.The Flash memory access time for a
read access is increased as compared to range 1. Write and erase operations are
possible.
3.9.4 VBAT operation
The VBAT pin is used to power the device VBAT domain (RTC, LSE and backup registers)
from an external battery, an external super-capacitor, or from V
DD
when no external battery
nor an external super-capacitor are present. Three anti-tamper detection pins are available
in VBAT mode.
VBAT operation is automatically activated when V
DD
is not present.
An internal V
BAT
battery charging circuit is embedded and can be activated when V
DD
is
present.
Note: When the microcontroller is supplied only from V
BAT
, external interrupts and RTC
alarm/events do not exit it from VBAT operation.
3.10 Low-power modes
The devices support several low-power modes to achieve the best compromise between
low-power consumption, short startup time, available peripherals and available wakeup
sources.
By default, the microcontroller is in Run mode, range 1, after a system or a power-on reset.
It is up to the user to select one of the low-power modes described below:
Sleep mode: CPU clock off, all peripherals including CPU core peripherals (among
them NVIC, SysTick) can run and wake up the CPU when an interrupt or an event
occurs.
Low-power run mode (LPRun): when the system clock frequency is reduced below
2 MHz. The code is executed from the SRAM or from the Flash memory. The regulator
is in low-power mode to minimize the operating current.
Low-power sleep mode (LPSleep): entered from the LPRun mode.
Stop 0 and Stop 1 modes: the content of SRAM1, SRAM2 and of all registers is
retained. All clocks in the VCORE domain are stopped. PLL, MSI, HSI16 and HSE32
are disabled. LSI and LSE can be kept running.
RTC can remain active (Stop mode with RTC, Stop mode without RTC). The sub-GHz
radio may remain active independently from the CPU.
Some peripherals with the wakeup capability can enable HSI16 RC during the Stop
mode to detect their wakeup condition.
Stop 1 offers the largest number of active peripherals and wakeup sources, a smaller