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/**
@page PWR_EnterStandbyMode PWR standby example
@verbatim
******************************************************************************
* @file Examples_LL/PWR/PWR_EnterStandbyMode/readme.txt
* @author MCD Application Team
* @brief Description of the PWR STANDBY mode example.
******************************************************************************
*
* Copyright (c) 2019-2021 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
@endverbatim
@par Example Description
How to enter the Standby mode and wake up from this mode by using an external
reset or a wakeup pin.
In the associated software, the system clock is set to 64 MHz.
An EXTI line is connected to the User push-button (SW1) through PA.00 and configured to generate an
interrupt on falling edge upon key press.
Request to enter in standby mode:
When a falling edge is detected on the EXTI line, an interrupt is generated.
In the EXTI handler routine, the wake-up pin LL_PWR_WAKEUP_PIN1 is enabled and the
corresponding wake-up flag cleared. Then, the system enters Standby mode causing
LED2 to stop toggling.
Exit from Standby mode:
The user can wake-up the system in pressing the User push-button (SW1) which is
connected to the wake-up pin LL_PWR_WAKEUP_PIN1.
A falling edge on WKUP pin will wake-up the system from Standby.
Wake-up pin connection: On board STM32WB Nucleo64, pin PA0
Alternatively, an external reset (reset button on board) will wake-up system from Standby
as well as wake-up pin.
After wake-up from Standby mode, program execution restarts in the same way as
after a reset and LED2 restarts toggling.
These steps are repeated in an infinite loop.
LED2 is used to monitor the system state as follows:
- LED2 fast toggling (each 200ms): system in Run mode from reset (power on reset or reset pin while system was in Run mode)
- LED2 slow toggling (each 500ms): system in Run mode after exiting from Standby mode
- LED2 off: system in Standby mode
@note To measure MCU current consumption on board STM32WB Nucleo,
board configuration must be applied:
- remove all jumpers on connector JP5 to avoid leakages between ST-Link circuitry and STM32WB device.
- remove jumper JP2 and connect an amperemeter to measure current between the 2 connectors of JP2.
@note On STM32WB, both CPU1 and CPU2 must be in Standby mode to set the entire system in Standby mode.
In this example, RF stack is not started-up, therefore CPU2 is not started-up and CPU1 configures the CPU2 low-power mode.
If this example would be ported to another application, user should start RF stack or manage CPU2 low-power mode.
@note This example can not be used in DEBUG mode due to the fact
that the Cortex-M4 core is no longer clocked during low power mode
so debugging features are disabled.
@par Keywords
Power, PWR, Standby mode, Interrupt, EXTI, Wakeup, Low Power, External reset,
@par Directory contents
- PWR/PWR_EnterStandbyMode/Inc/stm32wbxx_it.h Interrupt handlers header file
- PWR/PWR_EnterStandbyMode/Inc/main.h Header for main.c module
- PWR/PWR_EnterStandbyMode/Inc/stm32_assert.h Template file to include assert_failed function
- PWR/PWR_EnterStandbyMode/Src/stm32wbxx_it.c Interrupt handlers
- PWR/PWR_EnterStandbyMode/Src/main.c Main program
- PWR/PWR_EnterStandbyMode/Src/system_stm32wbxx.c STM32WBxx system source file
@par Hardware and Software environment
- This example runs on STM32WB15CCUx devices.
- This example has been tested with STMicroelectronics NUCLEO-WB15CC
board and can be easily tailored to any other supported device
and development board.
- NUCLEO-WB15CC Set-up
- LED2 connected to PB.00 pin
- User push-button connected to pin PA.00 (External line 0)
- WakeUp Pin LL_PWR_WAKEUP_PIN1 connected to PA.0
@par How to use it ?
In order to make the program work, you must do the following :
- Open your preferred toolchain
- Rebuild all files and load your image into target memory
- Run the example
* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
*/
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