$5 AliExpress Clock Modules

Two clock modules built on the same PCB, but using very different operating techniques. https://www.aliexpress.com/item/10050... https://www.aliexpress.com/item/10050... https://www.mikrocontroller.net/attac... https://www.nscn.com.cn/epson_pdf/RTC... https://ww1.microchip.com/downloads/e...