Bulgarian open hardware specialist Olimex has announced a new single-board computer (SBC) design, built around the Espressif ESP32 microcontroller — and designed with FabGL programming and retro-gaming emulation firmly in mind.
"I learned about the FabGL library when we started manufacturing Agon Light 2," Olimex founder Tsvetan Usunov explains, referring to his fork and respin of Barnardo Kastrup's Agon Light Zilog Z80-based SBC. "The ESP32 was used as a graphics, sound, and IO [Input/Output] keyboard co-processor for Bernardo’s Z80 design. Upon checking the library, I discovered that the author, Fabrizio Di Vittorio, had already created several emulators for Altair 8080, [Commodore] VIC20, and even old DOS PCs!"
That was enough to pique Usunov's interest in designing a board tailored specifically to FabGL: the ESP32-SBC-FabGL. "I wanted to create a board that could be used as a graphics/sound/IO co-processor for other retro computers based on different processors," Usunov explains. "As you may guess, this will be very convenient platform to create retro computers based on [the] same principle as Agon Light 2, so some retro computers based on this platform will follow, but do not ask when."
The board is built around an Espressif ESP32-WROVER module, pairing an ESP32 microcontroller with an additional 4MB of flash memory and 8MB of pseudo-static RAM (PSRAM). There's a VGA connector for an external display, as well as a header for an LCD add-on, a 3.5mm analog audio jack, PS/2 connectors for a keyboard and mouse, microSD storage, and Olimex's trademark UEXT connector for external hardware. There's even a lithium-polymer battery header, plus an on-board buzzer which can be enabled or disabled with a hardware jumper.
An interesting twist in the design is what Usunov calls the "Access Bus" header. "The Access Bus will provide [an] interface to retro processor HATs [Hardwares Attached on Top] for graphics, sound, keyboard and mouse," he explains. "The LCD HAT will allow handheld game consoles to be created easily."
The first production prototypes of the ESP32-SBC-FabGL are currently undergoing testing, having already proven their support for all the various FabGL demos — including emulating an Altair 8080 running Digital's CP/M and an IBM PC running MS-DOS.
Pre-orders will open soon, Usunov promises in the announcement blog post, priced at €15 (around $16), with shipping in June. "In this price is included royalties for the Author of FabGL," Usunov adds, "so by buying this board you will support Fabrizio and his further developments."