Unlocking the Secrets of the UDC Disk Controller #VintageComputing #Apple
Big Mess o’ Wires has been spending a great deal of time studying the Apple II era Universal Disk Controller in order to build one with modern hardware.
I concluded my last post about my Yellowstone disk controller for Apple II by saying I would probably support intelligent Smartport drives and 5.25 inch drives, but not 3.5 inch drives. But since then I’ve been busy investigating the possibility of a multi-purpose disk controller that could support all three drive types, by studying the Universal Disk Controller (UDC) that was marketed by Laser, VTech, and CPS. I’ve made some good progress, but big mysteries still remain.
There were two physical versions of the UDC: the original “long” version and the later “short” version. There were also at least four different firmware versions, and probably many more. The UDC’s capabilities may have changed substantially between versions.
Check their code analysis and quandaries between firmware versions in the post here.
8-6-2021 (August 6, 2021) is the Snakiest day of the year and it’s also this year’s CircuitPython Day! The day highlights all things CircuitPython and Python on Hardware. See you there!
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.