Return to the Wild West of Computing with PicoGraph
Role play as a '90s GPU engineer with PicoGraph, a Pi Pico 2 tool that emulates vintage ISA graphics so you can hack more FPS out of Doom!
There is a certain mystique surrounding the pioneers of early personal computing systems. Now everything is standardized, and the best you can hope for in a new machine is incremental upgrades. But back between the 1970s and 1990s, the world of personal computing was the Wild West and computer engineers were cowboys that didn't follow the rules. The status quo could be shattered at any time by a massive hardware upgrade like a Voodoo or a Sound Blaster that seemingly appeared out of nowhere.
Those days may be long gone, but now you can role play as a GPU hardware engineer from the era. Ian Hanschen has developed a tool called PicoGraph that plugs into the ISA bus of a vintage computer and emulates a graphics card with modern hardware. Using this platform, you can experiment as much as you like to see if you can squeeze a few more FPS out of Doom.
Wrangling the Raspberry Pi Pico 2
Hanschen built the project around a Raspberry Pi Pico 2 microcontroller development board. This board is mounted on FreddyV’s PicoMEM v1.4 ISA adapter to create PicoGraph. This system transforms modern hardware into a very capable retro graphics accelerator for IBM PC-compatible systems. The setup works with both 8-bit and 16-bit ISA slots, making it compatible with a wide range of vintage motherboards from the DOS era.
PicoGraph’s custom firmware can emulate old-school MDA and Hercules graphics for monochrome applications, as well as EGA, VGA, and the Cirrus Logic CL-GD5429 SVGA chipset. This means software written for decades of PC graphics hardware can potentially run through a single Pico-powered card.
Sending pixels down a different trail
Instead of outputting video through a traditional VGA connector, PicoGraph takes a more unconventional route. The device sends video frames over USB using a modified DisplayLink implementation combined with TinyUSB. The Pico can host compatible USB DisplayLink adapters and stream compressed retro graphics data using run-length encoding for compression. It is an unusual but clever workaround that avoids many of the headaches associated with vintage video standards.
The firmware for PicoGraph has been released under an open source license. It is available for download from the project’s GitHub repository.