Thanks to the 15mm x 15mm ATSAMA5D27 package from Microchip, this company created a 20mm x 20mm Linux computer roughly the size of a coin.
Small computers have been getting posted over at Hacker News, so I figured I’d share this one here in !technology.
You solder them onto the edges.
https://d3s5r33r268y59.cloudfront.net/datasheets/23894/2021-06-09-13-30-09/Hane-SOM-Full_SoM_pinout.pdf
There’s the pinout. This is a common technique for electronics. See Sparkfun for a good tutorial: https://learn.sparkfun.com/tutorials/how-to-solder-castellated-mounting-holes/all