I tested the accuracy of Arduino's Real-Time Clock (RTC) and compared it with millis(). The results are shocking - especially for the new R4 boards. Detailed testing and comparison between: - Arduino Uno R4 WIFI - Arduino Uno R4 MINIMA - Arduino Diecimila - Arduino Duemilanove - Arduino Uno R2 - Arduino Uno R3 Deep dive into the Renesas R7FA4M1 chip's documentation reveals why the R4's RTC accuracy is problematic. Spoiler: It's about HOCO, MOCO, and LOCO (yes, those are real names). If you're planning to use Arduino's RTC for time-sensitive projects, you need to watch this first. Love these videos? Consider becoming a Channel Member to support more content like this! Thank you! Affiliate Links to my gear: Blackmagic micro studio camera 4k DE: Blackmagic ATEM mini extreme iso DE: RØDE NTG2 DE: ART Tube MP DE: