Olimex Forks Bernardo Kastrup's Agon Light, Offers a Tweaked Z80 Single-Board Computer Design
Impressed by the original design, Olimex founder Tsvetan Usunov has created a customized — and lower-cost — alternative.
Bernardo Kastrup's Agon Light single-board computer, designed for retro-heads eager to experiment with BBC Basic on a Zilog Z80-compatible processor, is getting its first major fork — with Bulgarian open hardware specialist Olimex converting the project to KiCad and tweaking the design for cost and usability ahead of a full production run.
"Agon Light is a fully open-source 8-bit microcomputer and microcontroller in one small, low-cost board, built with state-of-the-art 21st-century technology," Kastrup explains of the original design, available on GitHub under an open source license. "It has two claims to fame — in a nutshell: Agon Light is the fastest and cheapest 8-bit microcomputer ever made; [and] in addition, Agon Light is the world's sole standalone, instant-on, BASIC-programmed microcontroller that dispenses with a host PC and sketch compilation. This allows projects to be controlled from the immediacy of a BASIC interpreter's prompt."
Olimex founder Tsvetan Usunov received a number of queries as to whether his company, which has a history with open source retro-themed single-board computers, would be producing a version of the Agon Light — but decided to make a few tweaks before listing the board for sale, producing the project's first major fork.
"After exchanging a few words with Bernardo via Twitter, we became confident that this is a true open source hardware project," Usunov explains. "We checked the schematic and decided to do some small changes."
The first of those: taking the original project design files, created in EasyEDA, and recreating them in KiCad format. Then, using those files, making a few design tweaks: replacing a USB Type-A connector, previously used with a Type-A to Type-A cable to power the board, with a USB Type-C connector; swapping a linear voltage regulator for a 2A-capable DC-DC converter; adding a lithium-polymer battery charging circuit; replacing the PS/2 keyboard connector for a USB port, though one that still requires a connected USB keyboard to have a PS/2 fallback mode; and the addition of a UEXT connector for solderless linking to external hardware.
"We changed most of the components to our component base, which we source and stock in large quantities and allow us to bring the cost down," Usunov adds. "Next week we will assemble 5 pcs to test by ourselves and then send to the original Agon Light developers. Agon Light will be put on our web and available for pre-order next week with a special Christmas price of €50 [around $52] for a completely assembled, programmed, and tested computer."
More information is available on the Olimex blog; once orders open, hardware is expected to ship by the end of January 2023. The KiCad design files for the revised board will follow after testing, Usunov has confirmed.