SGI - PS/2 keyboard and mouse converter

About

This project is a converter for connecting PS/2 keyboards and mice to old Silicon Graphics computers which had a proprietary keyboard/mouse interface. It should work on every non-PS/2 SGI computer with mini-DIN6, DB9 and DB15 keyboard/mouse connectors, such as:

• Iris 4D series
• Onyx
• Indigo

This converter is not necessary, and will not work, for any later SGI machines, like the indy, O2, indigo2, Octane, and so on, because they use PS/2 keyboards and mice directly.

It's based on an AVR atmega328pb microcontroller, which reads the PS/2 keyboard and mouse ports, and translates scancodes and events to the protocol and electrical signalling used by the SGI computers. For details on the SGI signalling and protocols, see the copy of the keyboard and mouse manpages from the section 7 of the IRIX manual, under doc/.

Directory structure:

• hw - hardware: kicad files and pdf schematics.
• fw - firmware for the AVR microcontroller.
• case - 3D printable enclosure for the sgikbd board.
• doc - relevant documentation.

This repository only contains source files. For schematics in PDF format, zipped gerbers for PCB manufacturing, and human-readable bill of materials, as well as detailed build instructions, visit the project website: http://nuclear.mutantstargoat.com/hw/sgikbd

Alternatively download the latest release archive from: https://github.com/jtsiomb/sgikbd/releases

The firmware is based on my previous a500kbd project, so if you see any leftover references to the Amiga anywhere don't be confused.

Note: rev3 of the sgikbd board uses a jumper (J2) to select the negative supply voltage source. Make sure to install a jumper there, do not leave it open. In most cases the jumper should be placed in the "default" position, but for some workstations (notably the R3000 indigo) which don't provide a negative supply on the keyb/mouse port, you might have to move it to the "R3k indigo" position instead.

For previous revisions of sgikbd, see these instructions on how to hack it to work with the R3000 indigo.

License

Copyright (C) 2017-2025 John Tsiombikas [email protected]

You are free to use, reproduce, modify, and redistribute any part of this project, provided you make any derivative work you release, freely available under the same terms.

Both hardware designs, and software parts of this project, are released under the terms of the GNU General Public License v3, or at your option any later version published by the Free Software Foundation. See LICENSE for details.

To comply with the license, when releasing derivative hardware designs, you must provide the full EDA project files, and of course firmware/software source code. Releasing only images of schematics, gerbers, and firmware binaries is not sufficient for compliance.