TRS80 Model I EI RevD

TRS-80 Model 1 Expansion Interface Replica Rev D - E1

This project is a faithful reimplementation of the Expansion Interface (Revision D) of the iconic TRS-80 Model 1 computer system. My own revision, the E1, is designed to replicate the original board's functionality by using a PCB design 1-to-1 to the original, including components, interfaces, and even traces. The Expansion Interface extends the base Model 1 with additional dynamic RAM, a floppy disk controller, a parallel printer port, a second cassette interface, and a real-time clock. The entire project is available under the MIT license.

NOTE: This project has not been confirmed yet to be 100% working. I am fairly certain it is correct, but I am waiting on the board to be tested in the real-world.

Project Details

Latest Files

In the "Latest" folder, you'll find the most up-to-date design files, including:

• Gerber files suitable for popular online PCB manufacturers like PCBWay and JLCPCB. Most manufacturers should be fine with either.
• A Bill of Materials (BOM) in both CSV and PDF formats.
• The full schematics of the E1 replica which is 1:1 to the original Revision D board.

Ordering Instructions

When ordering the board from a PCB manufacturer, you can select the following to get a more faithful version of the board:

Dimension: 302mm x 195mm
Layers: 2
Base Material: FR-4 TG 135-140 (and up)
PCB Thickness: 1.6mm
PCB Color: Green
Silkscreen Color: White
Via Covering: Untented
Surface Finish: Lead Free HASL
Outer Copper Weight: 1oz
Gold Fingers / Card Edge: yes (chamfer: 30 degrees)
Castellated Holes: no

Additionally, supply the following comment for the manufacturer:

There are three sides for card-edge. I understand that there will be a chamfer along the board on all three sides. That is ok and expected.

This addresses recurring questions.

Implementation

E1 has been implemented using KiCAD 9. The KiCAD project files are included in this repository.

RetroStack Libraries

To work with this KiCAD project, you'll need the RetroStack libraries for KiCAD. Please follow this link to access and install these libraries.

Main TRS-80 Model 1 Repository

For additional resources related to the TRS-80 Model 1, be sure to check out the central page for the TRS-80 Model 1 on RetroStack. You can find it here.

Support this Project

RetroStack is passionate about exploring and preserving the legacy of older computer systems. My work involves creating detailed documentation and videos to share the knowledge. I am also dedicated to reviving these classic systems by reimplementing them and offering replacement parts at no cost. If you're keen on supporting this unique project, I invite you to visit my Patreon page. Your support would be immensely valuable and greatly appreciated!

License

This project is licensed under the MIT License - see the LICENSE file for details.