I've been working on an open source pure digital HDMI mod for the Neo Geo MVS, MV1C, and wanted to share it with the community.
NeoPico HD uses a Raspberry Pi Pico 2 (RP2350B) to tap the digital video and audio signals directly from the MVS board, before they hit the DACs. The result is a pure digital signal path from the Neo Geo to the display.
Features:
- 480p HDMI output (240p line-doubled) via pico_hdmi
- 15-bit RGB capture directly from NEO-B1 digital outputs
- DARK/SHADOW signal support for accurate brightness
- Digital audio capture from I2S bus (~55kHz -> 48kHz SRC)
- Zero-lag scanline-by-scanline output
How it works:
- Core 0: PIO captures 18-bit video (RGB555 + DARK + SHADOW) at 6MHz pixel clock
- Core 1: HSTX outputs HDMI with audio Data Islands
- Hardware interpolator + LUT handles RGB555->RGB565 conversion in a single cycle
Hardware needed:
- WeAct RP2350B (~$5)
- HDMI connector
- ~20 wires to resistor tap points on MVS
Status:
The footage here https://x.com/fliperama86/status/2015490969580212636 is from my prototype board running to a Morph 4K. Also tested on RT4K.
Still in active development. I have a custom PCB on order from JLCPCB that I'm waiting to test. Planning to add an FPC connector for easier installation and eventually make it compatible with O-MVS shells.
I plan to add AES support in the future, which should just require a daughter board for audio ADC.
Links:
GitHub: https://github.com/fliperama86/neopico-hd
PicoHDMI library: https://github.com/fliperama86/pico_hdmi
Feedback welcome!
NeoPico HD uses a Raspberry Pi Pico 2 (RP2350B) to tap the digital video and audio signals directly from the MVS board, before they hit the DACs. The result is a pure digital signal path from the Neo Geo to the display.
Features:
- 480p HDMI output (240p line-doubled) via pico_hdmi
- 15-bit RGB capture directly from NEO-B1 digital outputs
- DARK/SHADOW signal support for accurate brightness
- Digital audio capture from I2S bus (~55kHz -> 48kHz SRC)
- Zero-lag scanline-by-scanline output
How it works:
- Core 0: PIO captures 18-bit video (RGB555 + DARK + SHADOW) at 6MHz pixel clock
- Core 1: HSTX outputs HDMI with audio Data Islands
- Hardware interpolator + LUT handles RGB555->RGB565 conversion in a single cycle
Hardware needed:
- WeAct RP2350B (~$5)
- HDMI connector
- ~20 wires to resistor tap points on MVS
Status:
The footage here https://x.com/fliperama86/status/2015490969580212636 is from my prototype board running to a Morph 4K. Also tested on RT4K.
Still in active development. I have a custom PCB on order from JLCPCB that I'm waiting to test. Planning to add an FPC connector for easier installation and eventually make it compatible with O-MVS shells.
I plan to add AES support in the future, which should just require a daughter board for audio ADC.
Links:
GitHub: https://github.com/fliperama86/neopico-hd
PicoHDMI library: https://github.com/fliperama86/pico_hdmi
Feedback welcome!
Statistics: Posted by fliperama86 — Sun Jan 25, 2026 6:32 pm — Replies 0 — Views 20