i m using STM32 for my design and i want to use STM32 internal RTC to store Date/Time. I am bale to configure RTC Sec interrupt and i am using LSI as RTC clock source. But i am facing problem with RTC accuracy. I have follow the steps for calibrating LSI clock source using TIM5 and set the RTC presclare accordingly. Still accuracy is not good. STM32 RTC time is running faster then my reference time. i notice that after every 3min there is 1Sec difference between reference time and STM32 RTC time. I Test with LSE as clock source and with that accuracy is good but i don't want to add extra 32.767 KHz crystal in design.
Any suggestion or feedback is welcome, Thanks in advance.
Effectively the is LSI around 40 kHz (between 30 kHz and 60 kHz), and need software calibration. But the precision of this calibation is depending on the HSE precision. Which precision do you expect, and why don't you use an extra crystal ?
