Eliott65
What if the 6502 kept all of its memory? Eliott65 is a system written from scratch for the Olimex Neo6502kbd computer: the kernel does not live in the 6502, but in the chip around it. This wiki tells the story of the experiment: how it works, what we measured, and what we learned along the way.
- 8 bytestaken by the system in the 6502's memory, out of 65,536
- 7.7 MHzthe 6502's measured speed with video on (v0.52), every cycle served by the RP2040
- 8programs at once, with a shell and Ctrl+Tab switching
- ≈ 5 µsfor a complete system call, measured by the 6502
&), then PS listing the three
processes. Captured from the Eliott65 emulator, which runs the same kernel as the board.Where to start
- Eliott65 for complete beginnersThe board in a photo, three diagrams, and the essentials without jargon.
- SpecificationsProcessor, ROM, RAM, resolutions, sound: the data sheet.
- The machineThe Neo6502kbd: a real 6502, but all of its memory is played by an RP2040.
- The system, piece by pieceBus, calls, video, USB, files, hibernation, multitasking, graphics.
- The workshopThe probe, the emulator, the method and the mistakes we learned from.
What Eliott65 does today
- It boots into a program placed in memory, with no loader left behind.
- It shows a text screen of 40 × 30 characters in 16 colours, and 320 × 240 graphics with tiles and sprites, on the HDMI socket.
- It reads the USB keyboard and a USB stick (FAT12, FAT16, FAT32), reads and writes files, and starts programs from the key.
- It runs up to 8 programs at once, even those that never give control back.
- It plays notes and melodies on the board’s speaker, without blocking the program.
- It hibernates: the whole machine fits in a file, and resumes exactly where it left off.
All of this has been measured and validated on the board; each article explains how.