I build 8-bit computers, and I'm making a video series about programming them.
Software developer and maker in Lincoln, Nebraska. Most of what is here is the AC6502 project — a family of homebrew 6502 machines, their firmware, their emulators, and the tools that go with them.
📺 youtube.com/@acwrightdesign · 🎮 acwrightdesign.itch.io · ✉️ acwrightdesign@gmail.com
A course in 6502 assembly language, taught one machine at a time.
In production — the first episode isn't out yet. The playlist is where episodes land as they go up, and everything being built for them is already public below.
It starts on a bare-bones single-board computer with eight LEDs and no display at all, where there is nothing sitting between you and the processor. Twenty episodes on the fundamentals — registers, memory, addressing modes, the instruction set, interrupts, cycles and timing — ending by building the game "Kill the Bit" on those eight LEDs.
From there I hope to climb through the machines that defined the 8-bit era: the Apple 1, the PET, the VIC-20, the Commodore 64, the Atari 800, the Apple II, the NES, the Atari 2600 and beyond. One new idea per machine.
You won't need any hardware to follow along — everything runs in an emulator in your browser.
| The playlist, as episodes go up | |
| 📂 6502-ASSEMBLY | Scripts, slides, type-in cards and every example program |
| 🕹️ KIMULATOR | Run the programs in your browser — no install, no account |
| 📖 6502-DOCS | The user's and programmer's guide for the AC6502 family |
Homebrew 6502 computers. All open source — schematics, gerbers and firmware — so build one if you want one.
| 6502-ACE | All-in-one Computer Experience — the whole family on a single board: 65C02, VGA video, SID audio, storage, serial, GPIO and a real-time clock |
| 6502-KIM | Keypad Input Monitor — a 65C02, a 24-key pad, a 16×2 LCD and eight LEDs. Boots into a hex monitor. The machine series 01 is taught on |
| 6502-DEV | Development Environment Vehicle — a Teensy 4.1 stands in for the CPU, with run/stop, single-step and a clock you can slow to a crawl |
| 6502-COB | Computer on a Backplane — the modular desktop: card slots, up to 544KB of RAM, and a card for every peripheral |
| 6502-VCS | Video Computer System — the console of the family: ROM cartridges, VGA out, SID sound and 2600-compatible joysticks |
| APL1 | A homebrew Apple 1 replica — 6502, 65C21 PIA and WozMon, with a microcontroller terminal adding PS/2 and serial |
| 6502-BIOS | The 32KB ROM every machine boots: the Kernal, the Monitor and BASIC. It probes the I/O slots, so missing cards are simply skipped |
| 6502-EMULATOR | The family, emulated — cycle-accurate 65C02, TMS9918 video, SID audio. Browser or desktop |
| 6502-KIMULATOR | The KIM in particular — pad, LCD and the eight LEDs on the bus. Browser or desktop |
| 6502-PICOCALC | The whole machine as one .uf2 for the ClockworkPi PicoCalc — a handheld AC6502 |
| 6502-ASM | Assembly programs beyond the ones in the series, each with a Makefile |
| 6502-PRG / 6502-CRT | Templates to start from — a program that loads into RAM, or a cartridge that overlays ROM |
| bin2woz | Binary → WozMon deposits, to paste into a machine over a serial terminal |
| cffs | Build and edit CompactFlash images from the command line — up to 256 disk banks |
| VT-AC | A VT terminal that could have existed but didn't — VT-100 compatible, with 256 colours and a graphics mode. Desktop, web and CLI |
| TMS9918-EDITOR | Character and screen editor for the TMS9918 VDP |
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