129 lines
6.0 KiB
Plaintext
129 lines
6.0 KiB
Plaintext
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/**
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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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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. Neither the name of STMicroelectronics nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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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 100 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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The LSE oscillator clock is used as RTC clock source. LSE oscillator clock usually
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delivered by a 32.768 kHz quartz, which can be one of the listed configurations
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depending the version of NUCLEO board hardware:
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- On-board oscillator : X2 crystal 32.768 kHz
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- Oscillator from external depending the version of NUCLEO board hardware.
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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 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 power on reset occurs:
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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 Using stdio.h may increase the code size, it is optional and intended only to
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ease the example by displaying the date variables (aShowTime and aShowDate) on the debugger.
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By default this option is enabled, user can disable it by commenting
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"#define DISPLAY_ON_DUBUGGER" in main.h file.
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@note Care must be taken when using HAL_Delay(), this function provides accurate
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delay (in milliseconds) based on variable incremented in SysTick ISR. This
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implies that if HAL_Delay() is called from a peripheral ISR process, then
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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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@note The clock setting is configured to have the max product performance (max clock frequency)
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so not optimized in term of power consumption.
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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 Header for main.c module
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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 source file
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@par Hardware and Software environment
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- This example runs on STM32F411xEx devices.
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- This example has been tested with STMicroelectronics STM32F4xx-Nucleo RevC
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boards and can be easily tailored to any other supported device
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and development board.
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- STM32F4xx-Nucleo RevC Set-up
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- Use LED2 connected to PA.05 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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* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
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*/
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