An engineer documented their process of building a custom CRT display adapter for an arcade machine. The project aimed to connect a modern computer to an arcade's original CRT, achieving a non-standard resolution and improving color depth. This involved overcoming limitations of existing solutions and creating a custom hardware and software stack.

The project utilized an RP2040 microcontroller and its Programmable I/O (PIO) to generate the precise timing signals needed for VGA. The initial attempts used PIO assembly for generating HSYNC and VSYNC pulses. The engineer then developed a Linux kernel module to interface with the DRM layer and send the framebuffer data over USB to the RP2040.

Ultimately, the engineer adopted the GUD USB display adapter protocol, streamlining the process. They wrote a custom gadget implementation for the RP2040. This approach allowed for a more efficient and elegant solution, successfully driving the arcade's CRT display. The project highlights the practicality of custom hardware solutions.

This project demonstrates how hobbyists can breathe new life into classic arcade machines. By leveraging modern microcontrollers and custom software, it's possible to overcome compatibility issues and enhance the visual experience. Future endeavors might explore further optimizations and support for even higher color depths or resolutions.