STM32CubeF7/Projects/STM32F723E-Discovery/Examples/RTC/RTC_Alarm/readme.txt

/**
  @page RTC_Alarm RTC Alarm Example
  
  @verbatim
  ******************************************************************************
  * @file    RTC/RTC_Alarm/readme.txt 
  * @author  MCD Application Team
  * @brief   Description of the RTC Alarm example.
  ******************************************************************************
  *
  * Copyright (c) 2016 STMicroelectronics. All rights reserved.
  *
  * This software component is licensed by ST under BSD 3-Clause license,
  * the "License"; You may not use this file except in compliance with the
  * License. You may obtain a copy of the License at:
  *                       opensource.org/licenses/BSD-3-Clause
  *
  ******************************************************************************
  @endverbatim

@par Example Description 

Configuration and generation of an RTC alarm using the RTC HAL API.

At the beginning of the main program the HAL_Init() function is called to reset 
all the peripherals, initialize the Flash interface and the systick.
Then the SystemClock_Config() function is used to configure the system
clock (SYSCLK) to run at 216 MHz.

The RTC peripheral configuration is ensured by the HAL_RTC_Init() function.
This later is calling the HAL_RTC_MspInit()function which core is implementing
the configuration of the needed RTC resources according to the used hardware (CLOCK, 
PWR, RTC clock source and BackUp). You may update this function to change RTC configuration.

@note LSE oscillator clock is used as RTC clock source by default.
      The user can use also LSI as RTC clock source. The user uncomment the adequate 
      line on the main.h file.
      @code
        #define RTC_CLOCK_SOURCE_LSE  
        /* #define RTC_CLOCK_SOURCE_LSI */
      @endcode
      LSI oscillator clock is delivered by a 32 kHz RC.
      LSE (when available on board) is delivered by a 32.768 kHz crystal.

HAL_RTC_SetDate() and HAL_RTC_SetTime() functions are called to initialize the 
time and the date.
HAL_RTC_SetAlarm_IT() function is then called to initialize the Alarm feature with 
interrupt mode.

In this example, the Time is set to 02:20:00 and the Alarm must be generated after 
30 seconds on 02:20:30.

LED6 is turned ON when the RTC Alarm is generated correctly.
The current time is updated and displayed on the debugger in aShowTime variable.

In case of error, LED5 is toggled with a period of one second.

@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
      based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
      a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower)
      than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
      To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
      
@note The application need to ensure that the SysTick time base is always set to 1 millisecond
      to have correct HAL operation.

@par Keywords

System, RTC, Alarm, wakeup timer, Backup domain, Counter, LSE, LSI

@Note<74>If the user code size exceeds the DTCM-RAM size or starts from internal cacheable memories (SRAM1 and SRAM2),that is shared between several processors,
 <20><><EFBFBD><EFBFBD><EFBFBD>then it is highly recommended to enable the CPU cache and maintain its coherence at application level.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>The address and the size of cacheable buffers (shared between CPU and other masters)  must be properly updated to be aligned to cache line size (32 bytes).

@Note It is recommended to enable the cache and maintain its coherence, but depending on the use case
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> It is also possible to configure the MPU as "Write through", to guarantee the write access coherence.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>In that case, the MPU must be configured as Cacheable/Bufferable/Not Shareable.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Even though the user must manage the cache coherence for read accesses.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Please refer to the AN4838 <20>Managing memory protection unit (MPU) in STM32 MCUs<55>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Please refer to the AN4839 <20>Level 1 cache on STM32F7 Series<65>

@par Directory contents 

  - RTC/RTC_Alarm/Inc/stm32f7xx_hal_conf.h    HAL configuration file
  - RTC/RTC_Alarm/Inc/stm32f7xx_it.h          Interrupt handlers header file
  - RTC/RTC_Alarm/Inc/main.h                  Header for main.c module  
  - RTC/RTC_Alarm/Src/stm32f7xx_it.c          Interrupt handlers
  - RTC/RTC_Alarm/Src/main.c                  Main program
  - RTC/RTC_Alarm/Src/stm32f7xx_hal_msp.c     HAL MSP module
  - RTC/RTC_Alarm/Src/system_stm32f7xx.c      STM32F7xx system source file


@par Hardware and Software environment

  - This example runs on STM32F722xx/STM32F723xx/STM32F732xx/STM32F733xx devices.
  - This example has been tested with STMicroelectronics STM32F723E-DISCOVERY 
    board and can be easily tailored to any other supported device 
    and development board.

@par How to use it ? 

In order to make the program work, you must do the following :
 - Open your preferred toolchain 
 - Rebuild all files and load your image into target memory
 - Run the example


 * <h3><center>&copy; COPYRIGHT STMicroelectronics</center></h3>
 */