Open AC-1 – Apple 1 Kit Assembled
“Open AC-1” = Open-source Apple Computer 1
Here is a simple Apple 1 kit – it’s more than an emulator, but less than a re-creation. I’d call it a “re-imagining” of Steve Wozniak’s historic Apple 1.
This is an assembled version of the kit. I had to build several of these in my development process. This is the latest version of the kit and has been fully tested and “burned-in” for 24 hours+.
Why did I create this kit?
The world certainly did not need another “work-alike” Apple 1. In fact, it’s possible nowadays to fully source and build your own exact replica of an Apple 1 (here’s mine):
While building an exact replica is fun and rewarding, it is a lot of work, expensive (around $1,000), and requires a lot of trouble-shooting and maintenance to keep it running.
Several years ago I read the book “Apple I Replica Creation: Back to the Garage” by Tom Owad and enjoyed the in-depth discussion of Steve Wozniak’s design and inspiration for the Apple 1, as well as Vince Briel’s work in creating the Replica 1.
My goal was to create a through-hole kit that can be assembled in a weekend, allow you to get a taste of what using an Apple 1 was like, load real Apple 1 software quickly and easily, and use modern easily-obtained peripherals (USB keyboard, VGA monitor, SD card). My real interest is building affordable kits, since I grew up in the generation of Heathkit, Altair 8800, COSMAC Elf, and the ZX-80/81 kits.
So while this is not a full-featured, historically accurate re-creation of the Apple 1, it is a pleasant kit – both fun to build and fun to show off.
What can this Apple 1 kit do?
Upon power-up you are in the system monitor (or “Wozmon”). This was the original interface hand-assembled by Steve Wozniak in 1976. It allows you to view and set memory contents, and run programs.
Also included in ROM is Steve Wozniak’s original Apple BASIC (the predecessor to Integer BASIC). The original Apple 1 required you to load this from a cassette tape, but for ease-of-use, it is included in ROM and instantly available.
I have also added extensions to obtain a catalog of programs available on the SD card, as well as the ability to load software with a simple command. Loading software is slow, but about the same speed as the original Apple 1 loading from a cassette.
Unfortunately the ability to save programs is not yet available (at least not easily, there are hacks to make this possible). As this is an open source project, I would assume that functionality could be implemented in the near future.
What is included in the kit?
You will receive a fully assembled Open AC-1. An SD card is provided with a small selection of Apple 1 software. You will need to provide a VGA monitor and a compatible USB keyboard.
You can download the Assembly/Operations manual here.
Here’s an Open AC-1 with a 4×3 VGA monitor and mechanical keyboard.
8 inch LED monitor (Amazon)
This project is a combination of multiple open-source and public domain efforts. I would like to acknowledge and thank the authors and creators.
Integer BASIC – Steve Wozniak – Steve hand assembled the BASIC interpreter and Wozmon included in ROM.
RC6502 Apple 1 SBC – Copyright Tor-Eirik Bakke Lunde GPL-3.0 license – Much of this project is an extension of his work.
VT100 Terminal – Copyright Geoff Graham GPL-3.0 license – His work provides the VGA output and character generation, which I modified to use the Apple 1 font and added some Apple 1 specific functionality.
USB Keyboard processing for the VT100 Terminal program – David Hansel GPL-3.0 license