A1plus is a multi-basic implementation of an Apple I emulator that runs on an Adafruit Trinket M0 or Neo Trinkey. It's an Apple I PLUS some extras.
NOTE: See DETAILS.md for information about compiling the program, terminal setup and operation.
While working on a real 6502 I got sidetracked by a lonely Adafruit Trinket M0 sitting on my desk doing nothing. I wondered if I could get a working Apple I emulator onto it. If you're not familiar with the SAMD21 chip it is based on, it has a reasonably high clock rate and a fair amount of flash and ram space. I decided to throw in some extra goodies while I was at it to make it worthwhile (see video). It worked reasonably well. With maximum compiler optimizations turned on, it seems to be running at around the equivalent of a 0.8Mhz 6502. Not great, but very usable and you can still have a lot of fun with it. Encouraged by that minor success I wanted to see how small I could go. Adafruit also has even smaller boards that plug directly into a USB port.
The Neo Trinkey was just the ticket, and plugs directly into a USB port without a cable. The chip specs are the same as the Trinket M0, but the LED's are different. I use the LED's to change color when you switch "ROM" banks (not shown in video). See below for a video showing the system in action. There is no audio in the video, but some text in the upper right corner will let you know what's happening. The video is captured from "cool-retro-term" which has a very fun simulation of analog monitors.
A1plus includes a custom command processor that allows switching between three different implementations of BASIC. It also includes a small collection of built-in programs you can run directly from the board. Additional programs can be "pasted" into the terminal or write your own.
You can have an Apple I (sort of) on your keychain! 😃
(if the video isn't showing automatically click here: video)
Here are the boards if you are interested:
Trinket M0 (https://www.adafruit.com/product/3500)
Neo Trinkey (https://www.adafruit.com/product/4870)
