I have a nice new-old-stock IBM XT 83-key Model F. I would have happily used a Soarer converter or an xwhatsit converter except for the fact that Soarer's is not open-source, and the binary blob targets an older Teensy board which is hard to find in the UK; and xwhatsit's controllers cannot be installed in this model keyboard without taking a hacksaw to the PCB and rigging up some custom ribbon connectors.
So here is my take on a fully NKRO USB converter for the 83-key Model F. It is an Arduino Sketch for the MICRO board, with source code. The README file has details of setting up the wiring, and RIG.jpg is a picture of the converter setup on a breadboard. The source code is heavily commented.
Due to limitations in Arduino's USB HID implementation, there is currently no support for Boot Protocol mode. This means is that you cannot use your 83-key board to hack your BIOS settings at boot time, as the converter requires the full HID implementation provided by the host OS.
The mapping of the keyboard's raw scancodes into USB Usage codes is via a simple array declared in the file XTUSBMAP.h, so you can hack the key arrangement to your heart's content.
I have not implemented any on-board keystroke processing for chords or macros. This can already be done in the host environment with things like IMEs or XCompose.
Hopefully something useful for somebody in here. Project sourcecode attached. Simply load up in the Arduino IDE.
Sean.
