116 lines
4.7 KiB
Plaintext
116 lines
4.7 KiB
Plaintext
/**
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@page RTC_Calendar RTC Calendar example
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@verbatim
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******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
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* @file RTC/RTC_Calendar/readme.txt
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* @author MCD Application Team
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* @brief Description of the RTC Calendar example.
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******************************************************************************
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* @attention
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*
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* Copyright (c) 2017 STMicroelectronics.
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* All rights reserved.
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*
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* This software is licensed under terms that can be found in the LICENSE file
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* in the root directory of this software component.
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* If no LICENSE file comes with this software, it is provided AS-IS.
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*
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******************************************************************************
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@endverbatim
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@par Example Description
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This example guides you through the different configuration steps by mean of HAL API
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to ensure Calendar configuration using the RTC peripheral.
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At the beginning of the main program the HAL_Init() function is called to reset
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all the peripherals, initialize the Flash interface and the systick.
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Then the SystemClock_Config() function is used to configure the system
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clock (SYSCLK) to run at 168 MHz.
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The RTC peripheral configuration is ensured by the HAL_RTC_Init() function.
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This later is calling the HAL_RTC_MspInit()function which core is implementing
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the configuration of the needed RTC resources according to the used hardware (CLOCK,
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PWR, RTC clock source and BackUp). You may update this function to change RTC configuration.
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LSE oscillator clock is used as RTC clock source. LSE oscillator clock usually
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delivered by a 32.768 kHz quartz.
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HAL_RTC_SetTime()and HAL_RTC_SetDate() functions are then called to initialize the
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time and the date.
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A key value is written in backup data register 0 to indicate if the RTC is already configured.
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The RTC is in the backup (BKP) domain, still powered by VBAT when VDD is switched off,
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so the RTC configuration is not lost if a battery is connected to the VBAT pin.
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The program behaves as follows:
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1. After startup the program checks the backup data register 0 value:
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- BKP_DR0 value not correct: (RTC_BKP_DR0 value is not correct or has not yet
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been programmed when the program is executed for the first time) the RTC is
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configured.
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- BKP_DR0 value correct: this means that the RTC is configured and the time
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and date are displayed on Debugger.
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2. When an External Reset occurs the BKP domain is not reset and the RTC configuration
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is not lost. LED4 is ON.
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3. When power on reset occurs:
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- If a battery is connected to the VBAT pin: the BKP domain is not reset and
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the RTC configuration is not lost. LED2 is ON.
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- If no battery is connected to the VBAT pin: the BKP domain is reset and the
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RTC configuration is lost.
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LED1 is turned ON when the RTC configuration is done correctly.
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The current time and date are updated and displayed on the debugger in aShowTime
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and aShowDate variables.
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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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System, RTC, Calendar, Backup Domain, Reset
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@par Directory contents
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- RTC/RTC_Calendar/Inc/stm32f4xx_hal_conf.h HAL configuration file
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- RTC/RTC_Calendar/Inc/stm32f4xx_it.h Interrupt handlers header file
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- RTC/RTC_Calendar/Inc/main.h Main program header file
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- RTC/RTC_Calendar/Src/stm32f4xx_it.c Interrupt handlers
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- RTC/RTC_Calendar/Src/main.c Main program
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- RTC/RTC_Calendar/Src/stm32f4xx_hal_msp.c HAL MSP module
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- RTC/RTC_Calendar/Src/system_stm32f4xx.c STM32F4xx system clock configuration file
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@par Hardware and Software environment
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- This example runs on STM32F407xx/417xx devices.
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- This example has been tested with STMicroelectronics STM324xG-EVAL RevC
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evaluation boards and can be easily tailored to any other supported device
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and development board.
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- STM324xG-EVAL RevC Set-up
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- Please ensure that JP19 is in position 2-3 to connect 3V battery to VBAT pin.
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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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*/
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