MicroWriter Redux.
I have decided to publish some of my “archaeological” work from last year on Cy Endfield’s MicroWriter. The original objective was to produce a cycle-accurate emulator. I do not currently have the free time to complete this project, so I will post my results here for anyone who might care to pick up the torch. Click on some of the images to see the full-resolution version.
MicroWriter Disassembled.
MicroWriter Circuit Board (Top View)
MicroWriter Circuit Board (Bottom View)
MicroWriter Reverse-Engineered Schematic. (Click to view.)
MicroWriter Reverse-Engineered Schematic, Eagle-ized. Not 100% Complete! (Click to view.)
MicroWriter EPROM Close-Up.
MicroWriter RomSucker Circuit. Easy to build, Applicable to Other Vintage Devices. (Click to view.) IC1 is an '8255A.'
MicroWriter RomSucker (Breadboard.)
- MW Rom Sucker Source Code.
- The extracted ROM itself.
- A history of the CPU used in the MicroWriter. Various versions of the 1802 were used in orbit.
- An attempt at a disassembly.
- A very incomplete emulator.
And now for something completely different:
A very basic web-based emulator of Endfield’s chording system. (Supports lower-case alphabet only.)
http://loper-os.nfshost.com/wp-content/mwredux/top_all_small.jpg is a PNG file.
Fixed, thanks.
I had no idea that the MicroWriter was powered by the 1802. My first programming job in college was to port the realtime services kernel from a system board powered by the 1802 to one powered by the 6809. This was an eye-opening project for many reasons, but one that sticks with me is the true beauty of the 1802 design. It was in many ways a metaprogrammable CPU (and I don’t mean microcode). Needless to say, they don’t make them like this anymore.
Very nice post.