STM32CubeF4

@verbatim
******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
* @file Examples_LL/RTC/RTC_TimeStamp/readme.txt
* @author MCD Application Team
* @brief Description of the RTC example.
******************************************************************************
*
* Copyright (c) 2017 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

This example guides you through the different configuration steps by mean of LL API
to ensure Time Stamp configuration using the RTC peripheral. Peripheral initialization
done using LL unitary services functions for optimization purpose (performance and size).

In this example, after start-up, SYSCLK is configured to the max frequency using the PLL with
HSI as clock source.

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

Configure_RTC_TimeStamp() function is then called to initialize the time stamp feature
with interrupt mode. It configures the time stamp pin to be rising edge and enables
the time stamp detection on time stamp pin.
LL_RTC_DATE_Config()and LL_RTC_TIME_Config() functions are then called to initialize the
time and the date.

The associated firmware performs the following:
1. After start-up the program configure the RTC (Time date) and enable the feature
timeStamp.

2. When applying a high level on the time stamp pin (PC.13) by pressing the User push-button,
a time stamp event is detected and the calendar is saved in the time stamp structures.
Each time the user presses on the User push-button, the current date and time stamp are updated and displayed
on the debugger (live watch) in aShowTimeStamp and aShowDateStamp variables .
The current time and date are updated and displayed on the debugger (live watch) in aShowTime, aShowDate variables .

- LED2 is toggling : This indicates that the system generates an error.

@par Keywords

RTC, Timer, Timestamp, Counter, LSE, LSI, Current time, Real Time Clock

@par Directory contents

- RTC/RTC_TimeStamp/Inc/stm32f4xx_it.h Interrupt handlers header file
- RTC/RTC_TimeStamp/Inc/main.h Header for main.c module
- RTC/RTC_TimeStamp/Inc/stm32_assert.h Template file to include assert_failed function
- RTC/RTC_TimeStamp/Src/stm32f4xx_it.c Interrupt handlers
- RTC/RTC_TimeStamp/Src/main.c Main program
- RTC/RTC_TimeStamp/Src/system_stm32f4xx.c STM32F4xx system source file

@par Hardware and Software environment

- This example runs on STM32F411xx devices.

- This example has been tested with NUCLEO-F411RE 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