Table 46. Mcu And Sub-Ghz Radio Operating Modes - STMicroelectronics STM32WL5 Series Reference Manual

Power control (PWR)
4. The SRAM2 content can optionally be retained when the PWR_CR3.RRS bit is set.
5. Only when the sub-GHz radio is active.
6. Some peripherals with wake-up from Stop capability can request HSI16 to be enabled. In this case, HSI16 is woken up by
the peripheral, and only feeds the peripheral that requested it. HSI16 is automatically put off when the peripheral does not
need it anymore.
7. HSE32 can be used by sub-GHz radio system.
8. UART reception is functional in Stop 0 and 1 modes. LPUART1 reception is functional is Stop 0, 1, and 2 modes. LPUART1
generates a wake-up interrupt on Start address match or received frame event.
9. I2Cx (x= 1, 2) address detection is functional in Stop 0 and 1 modes. I2C3 address detection is functional in Stop 0, 1, and
2 modes. I2C3 generates a wake-up interrupt in case of address match.
10. Voltage scaling range 1 only.
11. I/Os can be configured with internal pull-up, pull-down or floating in Standby mode.
12. The I/Os with wake-up from Standby/Shutdown capability are PA0, PC13 and PB3.
13. I/Os can be configured with internal pull-up, pull-down or floating in Shutdown mode, but the configuration is lost when
exiting the Shutdown mode.
Relation between MCU and sub-GHz radio operating modes
The CPUs and sub-GHz radio have their own operating modes, as defined in the table
below.
CPU operating
mode
Sleep, Calibration, Standby, Active
Run, Sleep
(FS, TX, RX)
Deep-Sleep
LPRun, LPSleep
Sleep, Calibration, Standby, Active
(FS, TX, RX)
Sleep, Calibration, Standby, Active
Stop 0
(FS, TX, RX)
Deep-Sleep
Stop 1 and Stop 2
Sleep, Calibration, Standby, Active
(FS, TX, RX)
Deep-Sleep
Standby
Sleep, Calibration, Standby, Active
(FS, TX, RX)
Shutdown Deep-Sleep
1. For more details on sub-GHz radio operating modes, see
2. In the MCU Run, Sleep and Stop 0 modes, the sub-GHz radio is prevented from entering Deep-Sleep mode.
3. When retaining SRAM2 in Standby mode, the MCU uses the low-power regulator (LPR) mode.
4. When the CPU is in Shutdown mode, the sub-GHz radio cannot be activated and is forced in Deep-Sleep mode.
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Table 46. MCU and sub-GHz radio operating modes

Sub-GHz radio operating
(1)
mode
(2)
(2)
(4)
LDO or SMPS regulator active, MCU running in main
regulator (MR) mode.
LDO and SMPS regulator off, MCU running in low power
regulator (LPR) mode.
LDO or SMPS regulator active, MCU running in low power
regulator (LPR) mode.
LDO or SMPS regulator active, MCU running in main
regulator (MR) mode.
LDO and SMPS regulator off, MCU using low power
regulator (LPR) mode.
LDO or SMPS regulator active, MCU using low power
regulator (LPR) mode.
LDO and SMPS regulator off, MCU regulator off or on in low
power (LPR) mode
LDO or SMPS regulator active, MCU regulator off or on in
low power (LPR) mode
LDO and SMPS regulator off, MCU regulator off
Section 5: Sub-GHz radio
RM0453 Rev 5
Description
(3)
.
(3)
.
(SUBGHZ).
RM0453