107 lines
4.5 KiB
Plaintext
107 lines
4.5 KiB
Plaintext
/**
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@page RTC_Standby RTC_LowPower_STANDBY example
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@verbatim
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******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
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* @file RTC/RTC_LowPower_STANDBY/readme.txt
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* @author MCD Application Team
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* @brief Description of the RTC STANDBY example.
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******************************************************************************
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* @attention
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*
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* <h2><center>© Copyright (c) 2016 STMicroelectronics.
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* All rights reserved.</center></h2>
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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 STANDBY mode and wake up from this mode using the RTC alarm event.
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This event is connected to EXTI_Line17.
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This example shows also how to calculate date on the STM32F1xx after waking up
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standby.
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In the associated software, the system clock is set to 24 MHz, the SysTick is
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programmed to generate an interrupt each 1 ms.
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The LSI clock is used as RTC clock source by default.
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In the associated software
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- the system clock is set to 24 MHz.
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- the EXTI_Line17 connected internally to the RTC Alarm event is configured
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to generate an interrupt on rising edge after 15s.
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The system enters STANDBY mode after configurating time, alarm and date:
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- time to 23h59:55
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- date to 31th of October 2014
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- alarm to 00h00:10.
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Before enter in STANDBY mode, date is saved in 3 different backup registers (day,
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month and year).
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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.
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As a day elapsed at the alarm event, a date update is performed:
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- read old date available in 3 backup registers
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- add 1 day to the old date
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- check that the new date is equal to 1st of November 2014.
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One of the above scenario can occur.
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- LED4 Toggle: HAL configuration failed (system will go to an infinite loop)
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- LED_BLUE ON: After wake-up, SW did not detect a day elapsed
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- LED_GREEN ON: day elapsed well detected but date update failed
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- LED_GREEN & LED_BLUE ON: date updtate performed correctly
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@note This example can not be used in DEBUG mode, this is due to the fact
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that the Cortex-M3 core is no longer clocked during low power mode
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so debugging features are disabled
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@note Care must be taken when HAL_RCCEx_PeriphCLKConfig() is used to select
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the RTC clock source; in this case the Backup domain will be reset in
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order to modify the RTC Clock source, as consequence RTC registers (including
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the backup registers) and RCC_CSR register are set to their reset values.
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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 need 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 Directory contents
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- RTC/RTC_LowPower_STANDBY/Inc/stm32f1xx_conf.h HAL Configuration file
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- RTC/RTC_LowPower_STANDBY/Inc/stm32f1xx_it.h Header for stm32f1xx_it.c
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- RTC/RTC_LowPower_STANDBY/Inc/main.h Header file for main.c
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- RTC/RTC_LowPower_STANDBY/Src/system_stm32f1xx.c STM32F1xx system clock configuration file
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- RTC/RTC_LowPower_STANDBY/Src/stm32f1xx_it.c Interrupt handlers
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- RTC/RTC_LowPower_STANDBY/Src/main.c Main program
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- RTC/RTC_LowPower_STANDBY/Src/stm32f1xx_hal_msp.c HAL MSP module
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@par Hardware and Software environment
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- This example runs on STM32F100xB devices
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- This example has been tested with STMicroelectronics STM32VL-Discovery
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evaluation board and can be easily tailored to any other supported device
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and development board.
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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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