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Hi HN, project author here. The source code and design files are on GitHub: https://github.com/74hc595/Amethyst https://github.com/74hc595/Amethyst Documentati

Hi HN, project author here. The source code and design files are on GitHub: https://github.com/74hc595/Amethyst https://github.com/74hc595/Amethyst Documentation is lacking, sadly. My intent was to create a series of in-depth videos describing how various aspects of the system work in detail, but I'm somewhat behind on that. For folks that say "using an ATMEGA is cheating":... I agree! That was a guiding principle behind my 6809 computer project (Ultim809)--use only period hardware and no programmable chips (apart from EPROM). Amethyst originated a bit differently. Initially it started out as a neat hack to get 8-bit color video from a non-overclocked AVR without expensive external chips. And then I discovered the mechanical keyboard community and was able to source keyswitches and keycaps, and, well, in for a penny, in for a pound.

JKCalhoun 7y ago
Matt, you're rockin'. Saw a link to this on YT via /r/mechanicalkeyboards I like the staggered key arrangement of your prototype better, but whatever. Your projects always inspire me.
JKCalhoun 7y ago
BTW, what is the Amethyst's story regarding modern displays? Most of us have tossed our CRTs.
- msarnoff 7y ago
  Works fine with the (now vestigial) composite input on modern TVs. I’ve also usd an upscaler called the RetroTINK 2X to convert composite to HDMI, and it has superb picture quality.
MuffinFlavored 7y ago
For this project, how are the 4KB of EEPROM used differently than the 16KB of application memory?
moralsupply 7y ago
Why not take some of the discrete components out and introduce another cpu to handle both video and sound? it would make the design much simpler and programming easier overall. Also, why not use a more capable cpu with more embedded ram? These things are very cheap nowadays.
- coldacid 7y ago
  Rather than another CPU, it would be a AV interface chip wouldn't it?
jonjacky 7y ago
Matt, may I ask how you made the documentation? It's wonderful - its appearance is so in-keeping with the whole project. The Ramforth Reference Manual cover page says 'Typeset on a Smith-Corona Coronet XL'. Did you use a word procssing program or text editor, if so, running on what? How do you keep the Coronet XL running in good repair?

JKCalhoun 7y ago

Matt, you're rockin'. Saw a link to this on YT via /r/mechanicalkeyboards I like the staggered key arrangement of your prototype better, but whatever. Your projects always inspire me.

JKCalhoun 7y ago

BTW, what is the Amethyst's story regarding modern displays? Most of us have tossed our CRTs.

msarnoff 7y ago
Works fine with the (now vestigial) composite input on modern TVs. I’ve also usd an upscaler called the RetroTINK 2X to convert composite to HDMI, and it has superb picture quality.

MuffinFlavored 7y ago

For this project, how are the 4KB of EEPROM used differently than the 16KB of application memory?

moralsupply 7y ago

Why not take some of the discrete components out and introduce another cpu to handle both video and sound? it would make the design much simpler and programming easier overall. Also, why not use a more capable cpu with more embedded ram? These things are very cheap nowadays.

coldacid 7y ago
Rather than another CPU, it would be a AV interface chip wouldn't it?

jonjacky 7y ago

Matt, may I ask how you made the documentation? It's wonderful - its appearance is so in-keeping with the whole project. The Ramforth Reference Manual cover page says 'Typeset on a Smith-Corona Coronet XL'. Did you use a word procssing program or text editor, if so, running on what? How do you keep the Coronet XL running in good repair?