ABC 806 Keyboard adapter

This project is released under the GNU General Public License v3.

Summary

This project contains the software needed to build a USB keyboard adapter for the Luxor ABC 806 computer.

Required hardware

• Arduino USB Host shield Uno (or compatible)
• Arduino USB Host shield USB Host shield

Required Software

• Arduino IDE

While the Arduino IDE is serviceable, VS Code together with the new Arduino plugin gives a far better development experience.

Library dependencies

• USB Host Shield Library 2.0

Pin mappings

This is how the pins should be mapped between the Arduino Uno board and the ABC 806 keyboard connector.

DIN pin     Signal      Arduino Pin
----------------------------------------------------------------
1           TxD         1
2           GnD         GND
3           RxD         0
4           TRxC        3
5           Keydown     2
6           +12v        Vin
7           Reset       Not connected

Information about the serial connection

The keyboard is connected to the B channel of the Z80 dart using an asynchronous serial connection. In addition to the serial connection the keyboard side generates a 10 khz signal as well as a keydown event, triggering a processor interrupt.

These are the setting of the serial connection:

- 650 baud
- 8 bits
- no parity
- 2 stop bits

Note on compatibility

Since the ABC 806 is closely related to ABC 800 C/M and ABC 802, its very likely that this project will work for those machine types as well. Its possible also that the project can be used with the ABC 1600 Unix workstation.