How to build an USB real-time clock (usb-rtc) for usage with low-cost Linux systems #piday #raspberrypi @Raspberry_Pi « Adafruit Industries – Makers, hackers, artists, designers and engineers!
USB RTC for Raspberry Pi | Real Time Clock For Raspberry Pi – SB Components Ltd
USB-RTC Module Released as a companion to the Retro-Printer Module | RetroPrinter.com