Introduction
=============
A real-time clock (RTC) is a computer clock that keeps track of the current time. RTCs are also present in almost any electronic device that requires accurate time keeping. The real-time clock (RTC) embedded in STM32 microcontrollers acts as an independent BCD timer/ counter.

Features
===============
- Calendar
- Alarm
- Auto wakeup
- Timestamp
- Tamper detection

- Programmable daylight saving time
- Didigal calibration
- Synchronization
- Reference clock detection
- Backup register
- Alternative function IO


Clock Source
=============
LSI  RC : 32 kHz

LSE OSC : 32.768 kHz

HSE OSC : 4-26 MHz

.. image:: /stm32F4 RTC clock source

Configuration
================