ADAM’74, a retro display for 8-bit computers #VintageComputers #Retrocomputers

The Adam74 is a little project that tries to act as a little terminal that a hobbyist might enjoy using for a small 8-bit computer they’re experimenting with.

It relies on 7 pins to represent a 7-bit ASCII character and another pin that the connected device strobes in order to tell the Adam74 that there is a character waiting on the input pins to buffer and display. The prevalence of easy-to-interface small LCD displays and inexpensive microcontrollers to drive them made this project a no-brainer.

Like a terminal, the Adam74 handles wrapping of text, scrolling. It also handles many control codes like carriage return and bell. Other control codes are re-interpreted to give a simple cursor control interface, etc.

In doing research on the early terminals it was no surprise that I would stumble upon the ADM-3A terminal. And it will not surprise you that I drew inspiration from this machine for both the general shape of the acrylic stand I designed for it as well as the name itself.

The “74” in Adam74 is meant to suggest the era: sometime around 1974.

Here are the parts needed to populate the PCB:

  • Teensy 4.0 (PJRC)
  • Color 320×240 ILI9341-based LCD display (PJRC and other places)
  • 74LVC245 level shifter (Adafruit and other places)
  • Buzzer (Adafruit and other places)
  • 100 ohm, 1/4 Watt resistor (2×)
  • 0.1uF ceramic capacitor (3×) (Adafruit and other places)
  • 1N4148 small signal diode (Adafruit and other places)
  • 0.1″ male header pin strip (Adafruit and other places)
  • 20 pin (2×10, 2.54mm pitch) IDC male connector (optional)

The source code as well as Gerber files (and an SVG file you can use to cut the acrylic stand) are up on the EngineersNeedArt GitHub repo and the project described here.

 


Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here: adafruit.com/editorialstandards

Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.

Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7:30pm ET! To join, head over to YouTube and check out the show’s live chat and our Discord!

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Join over 38,000+ makers on Adafruit’s Discord channels and be part of the community! http://adafru.it/discord

CircuitPython – The easiest way to program microcontrollers – CircuitPython.org


New Products – Adafruit Industries – Makers, hackers, artists, designers and engineers! — New Products 11/15/2024 Featuring Adafruit bq25185 USB / DC / Solar Charger with 3.3V Buck Board! (Video)

Python for Microcontrollers – Adafruit Daily — Python on Microcontrollers Newsletter: CircuitPython 9.2.1, What is DMA, PyConUS 2025 and More! #CircuitPython #Python #micropython @ThePSF @Raspberry_Pi

EYE on NPI – Adafruit Daily — EYE on NPI Maxim’s Himalaya uSLIC Step-Down Power Module #EyeOnNPI @maximintegrated @digikey

Adafruit IoT Monthly — Halloween, WiLo, and more!

Maker Business – Adafruit Daily — Checking in on Intel

Electronics – Adafruit Daily — Probe Compensation

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !



1 Comment

  1. Ricardo Bánffy

    Real shame the display is only 320×240. With a 640×480 one it’d be able to display a full 80×24 characters, just like a *real* ADM-3A.

Sorry, the comment form is closed at this time.