2 layers11.5 × 11.6 mm

ATTinyRTC
pgreenland/attinyrtcmodule
ATTiny85 RTC for Mac SE/30 (and possibly others), using universal serial interface (USI) peripheral
6 parts11MIT
Open-source boards designed in KiCad by pgreenland on GitHub, from 1 repository. A board’s address here is its repository’s there.

pgreenland/attinyrtcmodule
ATTiny85 RTC for Mac SE/30 (and possibly others), using universal serial interface (USI) peripheral