The R&D lab that I worked for purchased a couple of Rockwell AIM-65 single board computers. The AIM-65 used the 6502 microprocessor, and it had a built-in keyboard and 20 character printer. The printers were super helpful when debugging programs. The 6502 microprocessor powered the Commodore PET, the Apple II, and the Atari 2600 game console.
Photo by Jonas Svidras on Unsplash