# A MiSTer marquee that finally has style

An ESP32-C3 firmware turns the tiny secondary screen on a MiSTer FPGA board into a round GC9A01 display, or a rectangular Cheap Yellow Display, with artwork you design in a browser.

- Category: Interface (build)
- Device: [Cheap Yellow Display](https://afterware.xyz/d/cheap-yellow-display)
- Made by: [Erico Mendonca](https://github.com/doccaz/mister-tty2oled-esp32) on GitHub
- Original: https://github.com/doccaz/mister-tty2oled-esp32
- On Afterware: https://afterware.xyz/p/a-mister-marquee-that-finally-has-style

## Can I build this?

- Difficulty: Intermediate
- AI-buildability: 4/5 (The firmware and browser editor already exist, so the work is mostly flashing and light wiring of a round display to an ESP32-C3, plus designing artwork with AI help.)
- Time: A weekend
- Cost: $10–25
- Parts: ESP32-C3, GC9A01 round display, Cheap Yellow Display
- Tools: soldering iron, web browser

Estimates based on the original write-up. How the AI-buildability score works: https://afterware.xyz/ai-buildability

## Starter prompt

```
Based on "A MiSTer marquee that finally has style" on Afterware: https://afterware.xyz/p/a-mister-marquee-that-finally-has-style

Write ESP32-C3 firmware that drives a 240x240 GC9A01 round SPI display and listens for MiSTer's secondary display serial messages. Show the current core name and game title, and let the user load custom artwork per command. Keep it compatible with a browser-based flasher.
```

## Story

Most MiSTer marquees are a small monochrome OLED, the kind that has been sitting in a parts bin for years. Erico Mendonca wanted something with more style, so he wrote firmware for the ESP32-C3 that speaks MiSTer's existing secondary display protocol and drives round GC9A01 panels instead. If a circle isn't your thing, the same firmware runs on the Cheap Yellow Display for a rectangular version.

He didn't touch the MiSTer side at all. The ESP32 does all the art work. A web-based editor lets you build your own artwork and tie it to the commands the MiSTer actually sends, so the screen changes with the core and the game that's loaded. Flashing also happens in the browser, so setup doesn't require a toolchain. Multiple client displays can run off one system over WiFi, which is handy if you want to show the boot screen in several rooms at once.

## Resources

- [Firmware repo](https://github.com/doccaz/mister-tty2oled-esp32)
- [Hackaday article](https://hackaday.com/2026/10/29/putting-a-mister-marquee-on-a-better-display/)

Tags: mister, esp32-c3, gc9a01, round display, retro gaming, marquee, vibe-coded

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