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.

Clock Source

LSI RC : 32 kHz LSE OSC : 32.768 kHz HSE OSC : 4-26 MHz