/**
@page PWR_STOP1 PWR Example
@verbatim
******************************************************************************
* @file Examples_MIX/PWR/PWR_STOP1/readme.txt
* @author MCD Application Team
* @brief Description of the PWR_STOP1 example.
******************************************************************************
*
* Copyright (c) 2020 STMicroelectronics. All rights reserved.
*
* This software component is licensed by ST under BSD 3-Clause license,
* the "License"; You may not use this file except in compliance with the
* License. You may obtain a copy of the License at:
* opensource.org/licenses/BSD-3-Clause
*
******************************************************************************
@endverbatim
@par Example Description
How to enter the STOP 1 mode and wake up from this mode by using external
reset or wakeup interrupt (all the RCC function calls use RCC LL API
for minimizing footprint and maximizing performance).
In the associated software, the system clock is set to 48 MHz, an EXTI line
is connected to the user button through PA.00 and configured to generate an
interrupt on falling edge upon key press.
The SysTick is programmed to generate an interrupt each 1 ms and in the SysTick
interrupt handler, LED2 is toggled in order to indicate whether the MCU is in STOP 1 mode
or RUN mode.
5 seconds after start-up, the system automatically enters STOP 1 mode and
LED2 stops toggling.
The User push-button (B1) can be pressed at any time to wake-up the system.
The software then comes back in RUN mode for 5 sec. before automatically entering STOP 1 mode again.
Two leds LED2 and LED1 are used to monitor the system state as following:
- LED2 toggling: system in RUN mode
- LED2 off : system in STOP 1 mode
- LED2 and LED1 ON: configuration failed (system will go to an infinite loop)
These steps are repeated in an infinite loop.
Connect an amperemeter to jumper JP1 to measure the IDD current.
@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.
@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower)
than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
@note The application needs to ensure that the SysTick time base is always set to 1 millisecond
to have correct HAL operation.
@par Keywords
Power, PWR, stop mode, wake-up, external reset, Interrupt, low power mode
@par Directory contents
- Examples_MIX/PWR/PWR_STOP1/Inc/stm32wlxx_conf.h HAL Configuration file
- Examples_MIX/PWR/PWR_STOP1/Inc/stm32wlxx_it.h Header for stm32wlxx_it.c
- Examples_MIX/PWR/PWR_STOP1/Inc/main.h Header file for main.c
- Examples_MIX/PWR/PWR_STOP1/Src/system_stm32wlxx.c STM32WLxx system clock configuration file
- Examples_MIX/PWR/PWR_STOP1/Src/stm32wlxx_it.c Interrupt handlers
- Examples_MIX/PWR/PWR_STOP1/Src/main.c Main program
- Examples_MIX/PWR/PWR_STOP1/Src/stm32wlxx_hal_msp.c HAL MSP module
@par Hardware and Software environment
- This example runs on STM32WLxx devices
- This example has been tested with STMicroelectronics NUCLEO-WL55JC RevC
board and can be easily tailored to any other supported device
and development board.
- NUCLEO-WL55JC RevC set-up:
- Use LED2 and LED1 connected respectively to PB.09 and PB.15 pins
- User push-button (B1) connected to pin PA.00 (External line 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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