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  • jonathan 396 days ago | parent | on: Planck 6502 expandable retro computer
    Hi everyone, I designed this a few years ago, and I'm still working on more expansion cards for it. The whole hardware and software is open source. Take a look and let me know what you think. Cheers!
    • ddingus 393 days ago
      I want one!

      Hey, I noticed you have an SGI keyboard in the background in the photo on your project page.

      I have the same one! And I absolutely LOVE that keyboard. Should I end up with one of your neat machines, that is the keyboard I would use with it.

      I used that keyboard with both an Indy and O2 SGI IRIX machines, BTW.

    • bmonkey325 396 days ago
      This is crazy interesting. - How long did the first build take? - What inspired you to take in this build? - What is next?
      • jonathan 394 days ago
        Probably Ben Eater's videos. But his build was too minimalist for my taste, so I designed something with expansion in mind. The first version was inspired by the RC2014, which has a backplane and everything else on separate boards, but for the second version, I added things to the mainboard to make it a functional single board computer. Next thing I'm working on is a video output card, but it is proving extremely tricky. I also have a MIDI board in the pipeline.
        • ddingus 393 days ago
          What are you using for video output?

          Just curious:

          TTL, like an Apple

          Custom chip from say, TI?

          Microcontroller?

          FPGA?

          • jonathan 392 days ago
            I tried with an fpga, but it is difficult to get the needed features and performance at a reasonable price. I also tried with a RP2040, and this seems to be easier, although the performance is not quite there yet.
            • ddingus 377 days ago
              Have you looked at the Propeller chips from Parallax?

              The P1 can do retro grade graphics from very solid TV graphics through higher resolution VGA.

              The P2 can drive any display, had 640x480 HDMI capability built in, and analog video of all kinds is very well supported.

              It would work in both of the classic ways for you. One way is to have it read the actual video RAM when the CPU allows that, and the other would be for it to have its own video RAM and the CPU communicates to it in some fashion.

        • bmonkey325 394 days ago
          That’s really impressive. Once there is video beyond a terminal I can envision the project attracting so many more persons. My 1200xl is not going to live forever and I’m losing hope that revive machines is going to happen.

          Damned impressed with the project TBh

          • jonathan 392 days ago
            Some things already exist that can act as a dumb terminal, ie put the serial output to an VGA or HDMI screen, but I also want to be able to do graphics and stuff.

            Also, the keyboard input from a PS2 keyboard already exists and works fine, so the video is really the last missing piece.

  • jonathan 540 days ago | parent | on: The 6502/65C02/65C816 instruction set decoded
    Funny, because I was just using this yesterday to adapt my rust 6502 emulator to 65C02. It's not as useful as for the 6502 since the 65C02 instructions are much less regular, but I like that way of looking at the instruction set, I feel like it shows the underlying logic of the designers.
    • Screwtapello 540 days ago
      Programming in JavaScript feels like being adrift in a realm of pure thought. Programming in 6502, you can feel the electrons pulsing through the thin carpet beneath your feet.
  • jonathan 607 days ago | parent | on: The 6502 microprocessor resource
    You do not want to miss the forum either : http://forum.6502.org
    • jonathan 611 days ago | parent | on: A superoptimizer for 6502 instructions
      It’s a pity there are no examples of the output it generates, since I think it would help me understand what this does.
      • me 610 days ago
        A superoptimizer tries to find the shortest sequence of instructions that is semantically equivalent to a given sequence of code. Since the search space is pretty large, brute force approaches don't work here.

        You can find a good introduction to superoptimizers in Massalin's (known for the Synthesis self-optimizing OS) paper at https://dl.acm.org/doi/abs/10.1145/36177.36194

      • bmonkey325 610 days ago
        Or any kind of note on how good the current 3 op peephole is.
    • jonathan 611 days ago | parent | on: Forth: The programming language that writes itself
      Haha I've actually been trying to port it to a bootable x86 binary. Unsuccessfully so far :/
    • jonathan 612 days ago | parent | on: Forth: The programming language that writes itself
      I’m actually just done reading the whole post. I may have fallen into many rabbit holes. I’ll take a look at the rest of the site, if everything if of the same high quality it’s gonna be great!
    • jonathan 613 days ago | parent | on: Using VGA on a modern display
      I have a cheap VGA to HDMI adapter, which I use with a cheap USB "capture card". It works fine but seems to only output 1080p. This looks better and for $30, not much more expensive. I don't know how it is possible to buy it though... All Google links point to the extron website where there doesn't seem to be an option to buy it. Frustrating.
      • undefined 613 days ago
        Extron doesn't sell direct as far as I know, you have to either go with an authorized dealer or reseller typically.
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