r/FPGA • u/Substantial-Club-582 • 3h ago
Gowin Related I ported the MiSTer Game Boy Color core to a $25 Tang Nano 20K — using only open-source FPGA tools
I've been working on Open Pocket GBC, a Game Boy / Game Boy Color FPGA project for the Sipeed Tang Nano 20K.
The goal was to get the MiSTer Game Boy core running on a small Gowin FPGA without relying on the proprietary Gowin IDE.
The entire bitstream is built using open-source tools: Yosys, slang, GHDL, nextpnr-himbaechel, Apicula, and openFPGALoader.
What it currently supports:
- GB/GBC hardware emulation using the MiSTer core
- HDMI output at 480p with embedded stereo audio
- Pocket-style menu with game selection and display settings
- LCD grid, scanlines, DMG palettes, and GBC color correction
- Games stored in onboard SPI flash and loaded into SDRAM
- USB-UART remote control and a debug overlay
- Optional ST7735S SPI LCD output (simulation-verified, not yet hardware-tested)
The design uses 17,008 / 20,736 LUTs (82%) and 45 / 46 BSRAM blocks (97%), so fitting everything onto the 20K was quite a challenge.
HDMI, audio, menu navigation, and game loading have been tested on real hardware. There are still limitations, particularly save persistence and some untested peripheral paths.
The repository includes the RTL, build scripts, hardware documentation, and demos.