99 lines
4.3 KiB
Plaintext
99 lines
4.3 KiB
Plaintext
/**
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@page PWR_STANDBY PWR STANDBY example
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@verbatim
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******************************************************************************
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* @file PWR/PWR_STANDBY/readme.txt
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* @author MCD Application Team
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* @brief Description of the PWR Standby example.
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******************************************************************************
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*
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* Copyright (c) 2020 STMicroelectronics. All rights reserved.
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*
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* This software component is licensed by ST under BSD 3-Clause license,
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* the "License"; You may not use this file except in compliance with the
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* License. You may obtain a copy of the License at:
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* opensource.org/licenses/BSD-3-Clause
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*
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******************************************************************************
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@endverbatim
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@par Example Description
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How to enter the Standby mode and wake up from this mode by using an external
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reset or the WKUP pin.
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In the associated software, the system clock is set to 48 MHz, an EXTI line
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is connected to the User push-button (B1) thrum PA0 and configured to generate an
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interrupt on falling edge.
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The SysTick is programmed to generate an interrupt each 1 ms and in the SysTick
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interrupt handler, LED2 is toggled in order to indicate whether the MCU is in Standby or Run mode.
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When a FALLING edge is detected on the EXTI line, an interrupt is generated and the system wake up,
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the program then checks and clears the standby flag.
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After clearing the standby flag, the software enables wake-up pin PWR_WAKEUP_PIN1 connected to PA0, then
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the corresponding flag indicating that a wakeup event was received from the PWR_WAKEUP_PIN1 is cleared.
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Finally, the system enters again Standby mode causing LED2 to stop toggling.
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A FALLING edge on WKUP pin will wake-up the system from Standby.
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Alternatively, an external RESET of the board will lead to a system wake-up as well.
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After wake-up from Standby mode, program execution restarts in the same way as after
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a RESET and LED2 restarts toggling.
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Two leds LED2 and LED3 are used to monitor the system state as follows:
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- LED3 ON: configuration failed (system will go to an infinite loop)
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- LED2 toggling: system in Run mode
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- LED2 off : system in Standby mode
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@note To measure the current consumption in Standby mode, remove JP1 jumper
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and connect an amperemeter to JP1 to measure IDD current.
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@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
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based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
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a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower)
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than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
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To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
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@note The application needs to ensure that the SysTick time base is always set to 1 millisecond
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to have correct HAL operation.
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@par Keywords
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Power, PWR, Standby mode, Interrupt, EXTI, Wakeup, Low Power, External reset
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@par Directory contents
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- PWR/PWR_STANDBY/Inc/stm32wlxx_nucleo_conf.h BSP configuration file
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- PWR/PWR_STANDBY/Inc/stm32wlxx_conf.h HAL Configuration file
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- PWR/PWR_STANDBY/Inc/stm32wlxx_it.h Header for stm32wlxx_it.c
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- PWR/PWR_STANDBY/Inc/main.h Header file for main.c
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- PWR/PWR_STANDBY/Src/system_stm32wlxx.c STM32WLxx system clock configuration file
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- PWR/PWR_STANDBY/Src/stm32wlxx_it.c Interrupt handlers
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- PWR/PWR_STANDBY/Src/main.c Main program
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- PWR/PWR_STANDBY/Src/stm32wlxx_hal_msp.c HAL MSP module
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@par Hardware and Software environment
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- This example runs on STM32WL55JCIx devices
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- This example has been tested with STMicroelectronics NUCLEO-WL55JC RevC
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board and can be easily tailored to any other supported device
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and development board.
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- NUCLEO-WL55JC RevC Set-up
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- Use LED2 and LED3 connected respectively to PB.09 and PB.11 pins
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- User push-button (B1) connected to pin PA.00 (External line 0)
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- WakeUp Pin PWR_WAKEUP_PIN1 connected to PA0
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@par How to use it ?
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In order to make the program work, you must do the following :
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- Open your preferred toolchain
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- Rebuild all files and load your image into target memory
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- Run the example
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* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
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*/
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