What is a Real Time Clock (RTC), time measurements, Real time clock IC - tatanh1983/conchodom GitHub Wiki
PCF85263A Series 5.5 V Tiny Real-Time Clock/Calendar - DFN2626-10
https://www.futureelectronics.com/p/semiconductors--real-time-clocks/pcf85263atl-ax-nxp-9072128