The Agon is currently available in one flavour, the Agon Light.

Designed by Bernado Kastrup, the designer of the Cerberus 2080, with a little input from myself and Andy Toone, the Agon Light is a modern and fully open-sourced eZ80 based microcomputer with VGA output, audio, and PS/2 keyboard connectors.

The board has 512Kb of SRAM, and there is 128Kb of flash memory built into the eZ80. Additional storage can be added via the micro SD card connector.

Audio and video is handled by the VPD (Visual Display Processor) – an ESP32 running custom firmware on top of the FabGL library. The ESP32 is connected to the eZ80 via a fast serial link, and will enable code running on the eZ80 to output text, graphics and sound via BBC Basic-like character sequences (VDU commands). It will also send information back to the eZ80 such as keypresses and terminal status.

There are a number of GPIO ports exposed at the bottom of the board, connected to the spare eZ80 and ESP32 GPIO ports.

The Agon Light will boot into MOS on start-up. This is a DOS-like command-line and will allow the user to navigate around the SD card, perform file operations, and launch applications, and will be configurable via a text file on the SD card.

The MOS will also provide an API for application developers who are interested in coding for the Agon Light, and will include vectors for file and graphics terminal I/O for C and assembly language programmers.

For those who are looking for an easier language to code in, the Agon Light will come complete with a tweaked version of R.T.Russell’s excellent BBC Basic for Z80 on SD card. This can be configured to run on power-up for a genuine 8-bit experience, with the power of BBC Basic combined with Agon specific features: file I/O, colour graphics, sound, and access to the eZ80 GPIO ports.

Source code for the MOS, VPD and BBC Basic are available on GitHub, as are the manufacturing files and BOM for the PCB.

  1. Motherboard
  2. Development Toolchain
  3. Memory Map
  4. MOS
  5. VDP
  6. BBC Basic for Z80