98 lines
4.0 KiB
Plaintext
98 lines
4.0 KiB
Plaintext
/**
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@page PWR_EnterStandbyMode PWR standby example
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@verbatim
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******************************************************************************
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* @file Examples_LL/PWR/PWR_EnterStandbyMode/readme.txt
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* @author MCD Application Team
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* @brief Description of the PWR STANDBY mode 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 a wakeup pin.
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In the associated software, the system clock is set to 16 MHz.
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An EXTI line is connected to the User push-button (B1) through PA.00 and configured to generate an
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interrupt on falling edge upon key press.
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Request to enter in standby mode:
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When a falling edge is detected on the EXTI line, an interrupt is generated.
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In the EXTI handler routine, the wake-up pin LL_PWR_WAKEUP_PIN1 is enabled and the
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corresponding wake-up flag cleared. Then, the system enters Standby mode causing
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LED2 to stop toggling.
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Exit from Standby mode:
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The user can wake-up the system in pressing the User push-button (B1) which is
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connected to the wake-up pin LL_PWR_WAKEUP_PIN1.
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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 (reset button on board) will wake-up system from Standby
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as well as wake-up pin.
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After wake-up from Standby mode, program execution restarts in the same way as
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after a reset and LED2 restarts toggling.
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These steps are repeated in an infinite loop.
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LED2 is used to monitor the system state as follows:
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- LED2 fast toggling (each 200ms): system in Run mode from reset (power on reset or reset pin while system was in Run mode)
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- LED2 slow toggling (each 500ms): system in Run mode after exiting from Standby mode
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- LED2 off: system in Standby mode
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@note To measure MCU current consumption on board STM32WL Nucleo,
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board configuration must be applied:
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- remove all jumpers on connector JP8 to avoid leakages between ST-Link circuitry and STM32WL device.
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- remove jumper JP1 and connect an amperemeter to measure current between the 2 connectors of the jumper.
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@note This example can not be used in DEBUG mode due to the fact
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that the Cortex-M4 core is no longer clocked during low power mode
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so debugging features are disabled.
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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_EnterStandbyMode/Inc/stm32wlxx_it.h Interrupt handlers header file
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- PWR/PWR_EnterStandbyMode/Inc/main.h Header for main.c module
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- PWR/PWR_EnterStandbyMode/Inc/stm32_assert.h Template file to include assert_failed function
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- PWR/PWR_EnterStandbyMode/Src/stm32wlxx_it.c Interrupt handlers
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- PWR/PWR_EnterStandbyMode/Src/main.c Main program
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- PWR/PWR_EnterStandbyMode/Src/system_stm32wlxx.c STM32WLxx system source file
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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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- LED2 connected to PB.09 pin
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- User push-button connected to pin PA.00 (External line 0)
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- WakeUp Pin LL_PWR_WAKEUP_PIN1 connected to PA.0
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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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