Official page: frank.rh1.tech — hub for all FRANK boards and firmware.
SNES (Super Nintendo) emulator for Raspberry Pi Pico 2 (RP2350) with HDMI output, SD card ROM browser, NES/SNES gamepad, USB gamepad, PS/2 keyboard, and I2S audio support.
Based on Snes9x / snes9x2010.
| Contra III | Prince of Persia |
|---|---|
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| Lion King | ROM Selector |
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This firmware supports two board layouts (M1 and M2) on RP2350-based boards with integrated HDMI, SD card, and PSRAM:
- FRANK — RP Pico 2 development board with HDMI and additional I/O
- Murmulator — RP Pico 2 board with HDMI, SD card, and PSRAM
Both boards have the required peripherals built in — no additional wiring needed.
- Native 640x480 HDMI video output (doubled from 256x224 SNES resolution)
- SNES sound emulation (SPC700 + DSP) over I2S
- CRT scanline effect (toggle on/off)
- 8MB QSPI PSRAM for ROM loading and metadata
- SD card ROM browser with cover art, game info, animated SNES cartridge carousel, and plain file-browser view (Select+Start or Tab to toggle)
- Typing search in the ROM browser (PS/2 and USB keyboards)
- On-demand ROM loading (ROMs loaded from SD when selected, not at boot)
- NES and SNES gamepad support, auto-detected per port (NES pads map A/B; SNES pads get A/B/X/Y/L/R)
- USB gamepad support via native USB Host, with HID and XInput (Xbox 360) controllers
- First-connect menu A/B calibration wizard for unknown USB pads (learned bits saved to SD and reused on future boots)
- PS/2 and USB keyboard support
- SNES Mouse support over PS/2 or USB, routable to controller port 1 or port 2
- Configurable input routing (map any input device to Player 1 or Player 2)
- Master volume control with gain scaling
- Configurable frameskip (none / low / medium / high / extreme)
- Video layer toggles (BG1-4, sprites, transparency, HDMA)
- Audio settings (echo, interpolation)
- Runtime settings menu with persistence to SD card
- Welcome screen with animated SNES controller logo
- Visible "NO SD CARD DETECTED" screen when the SD is missing or fails to mount
- Raspberry Pi Pico 2 (RP2350) or compatible board
- 8MB QSPI PSRAM (mandatory)
- HDMI connector (directly connected via resistors, no HDMI encoder needed)
- SD card module (SPI mode)
- NES or SNES gamepad (directly connected) - OR -
- USB gamepad (via native USB port)
- I2S DAC module (e.g., TDA1387, PCM5102) for audio output
- PS/2 keyboard (optional)
Note: When USB HID is enabled (default), the native USB port is used for gamepad input. USB serial console is disabled; UART TX (GPIO 0) is used for debug output.
FRANK SNES requires 8MB PSRAM to run. You can obtain PSRAM-equipped hardware in several ways:
- Solder a PSRAM chip on top of the Flash chip on a Pico 2 clone (SOP-8 flash chips are only available on clones, not the original Pico 2)
- Build a Nyx 2 - a DIY RP2350 board with integrated PSRAM
- Purchase a Pimoroni Pico Plus 2 - a ready-made Pico 2 with 8MB PSRAM
Two GPIO layouts are supported: M1 and M2. The PSRAM pin is auto-detected based on chip package:
- RP2350B: GPIO47 (both M1 and M2)
- RP2350A: GPIO19 (M1) or GPIO8 (M2)
| Signal | M1 GPIO | M2 GPIO |
|---|---|---|
| CLK- | 6 | 12 |
| CLK+ | 7 | 13 |
| D0- | 8 | 14 |
| D0+ | 9 | 15 |
| D1- | 10 | 16 |
| D1+ | 11 | 17 |
| D2- | 12 | 18 |
| D2+ | 13 | 19 |
| Signal | M1 GPIO | M2 GPIO |
|---|---|---|
| CLK | 2 | 6 |
| CMD | 3 | 7 |
| DAT0 | 4 | 4 |
| DAT3/CS | 5 | 5 |
| Signal | M1 GPIO | M2 GPIO |
|---|---|---|
| CLK | 14 | 20 |
| LATCH | 15 | 21 |
| DATA 1 | 16 | 26 |
Note: Gamepad 2 uses the same CLK and LATCH as Gamepad 1, only the DATA pin differs.
| Signal | M1 GPIO | M2 GPIO |
|---|---|---|
| DATA | 26 | 9 |
| BCLK | 27 | 10 |
| LRCLK | 28 | 11 |
| Signal | M1 GPIO | M2 GPIO |
|---|---|---|
| CLK | 0 | 2 |
| DATA | 1 | 3 |
- Format an SD card as FAT32
- Create a
snesdirectory in the root - Copy
.smc,.sfc, or.figROM files into thesnes/directory - (Optional) Copy game metadata for cover art and game info - extract
sdcard/metadata.zipto your SD card'ssnes/directory - Insert the SD card and power on the device
The emulator also uses the SD card for:
snes/settings.ini— runtime settingssnes/.crc_cache— cached ROM checksumssnes/gamepads/gamepad_VVVV_PPPP.txt— per-pad menu A/B layouts learned by the USB HID calibration wizard
If the SD card is missing or fails to mount, the emulator now displays a visible "NO SD CARD DETECTED" error screen on boot instead of dropping into a silent LED-blink loop.
On the first boot, FRANK SNES scans all ROM files in snes/ and computes a CRC32 checksum for each one. This is used to look up cover art and game metadata. This can take a few seconds per file depending on ROM size.
The checksums are cached in snes/.crc_cache so subsequent boots are fast. The cache is automatically updated when new ROMs are added.
Tip: Keep the number of ROMs on your SD card reasonable (under 50). The ROM selector loads cover art on-the-fly as you browse.
On boot, a welcome screen is displayed with the FRANK SNES logo, version, and author information. Press A or Start to continue (or wait 10 seconds for auto-continue).
After the welcome screen, the ROM selector displays your game library as animated SNES cartridges with cover art. There are two views: the cartridge carousel and a plain file browser.
Carousel:
- Left / Right - Browse ROMs
- Up - Show game info panel (year, genre, players, description)
- Down - Hide game info panel
- A - Load selected ROM and start playing
- Select + Start / Tab - Toggle between carousel and file browser
- Select + Start + A / F12 - Open settings
File browser:
- Up / Down - Navigate entries
- A - Open directory / launch ROM (Start is reserved for combos)
- B - Go up a directory
- Type on a PS/2 or USB keyboard to open incremental search
- Select + Start / Tab - Back to carousel
- Select + Start + A / F12 - Open settings
The last selected ROM is remembered across reboots.
- Select + Start + A (gamepad), F12 or ESC (keyboard) - Open settings menu
Why the A? Bare Select + Start is reserved for toggling the carousel / file browser in the ROM selector and is therefore also reserved in-game for consistency.
For cover art and game info in the ROM selector, place metadata files on the SD card:
snes/metadata/images/{X}/{CRC32}.555 - Cover art (RGB555 format)
snes/metadata/descr/{X}/{CRC32}.txt - Game info (XML format)
Where {X} is the first hex digit of the CRC32, and {CRC32} is the 8-digit uppercase hex checksum (computed from ROM data, skipping the 512-byte copier header if present).
A pre-built metadata pack is included in sdcard/metadata.zip.
| SNES Button | Action |
|---|---|
| D-pad | Movement |
| A / B / X / Y | Buttons |
| L / R | Shoulder |
| Start | Start |
| Select | Select |
| Select + Start | Toggle ROM browser carousel / file view |
| Select + Start + A | Settings menu |
NES controllers are auto-detected per port on first use. A and B are routed to the SNES A and B buttons respectively; X/Y/L/R are unmapped (no source). Switching between NES and SNES pads on the same port requires a power cycle (detection is sticky).
USB HID and XInput (Xbox 360) gamepads are supported over the native USB port (USB HID enabled by default).
- Pads with a known VID/PID work out of the box (a growing list of captures lives in
gamepads/). - The first time an unknown pad is connected, a short on-screen wizard prompts you to press A, then B. The learned layout is saved to
snes/gamepads/gamepad_VVVV_PPPP.txton the SD card and reused from then on. In-game button mapping is unaffected — the wizard only teaches menu A/B. - Settings → Button Mapping → Clean USB Cache deletes those files and re-arms the wizard.
PS/2 and USB mice are supported as an SNES mouse. When a mouse is detected, the Mouse Port setting becomes available to route it to controller Port 1 or Port 2 (replacing the old on/off toggle). Mouse emulation engages automatically whenever a mouse is connected.
| Key | Action |
|---|---|
| Arrow keys | D-pad |
| X | A |
| Z | B |
| S | X |
| A | Y |
| Q | L |
| W | R |
| Enter | Start |
| Space | Select |
| Tab | Toggle ROM browser carousel / file view |
| F12 / ESC | Settings menu |
| F11 | Restart current game |
| Ctrl + Alt + Del | Restart current game |
| Any printable key | Start typing search in the ROM file browser |
Press Select + Start + A during gameplay (or F12 / ESC on keyboard) to open the settings menu:
| Setting | Options |
|---|---|
| Volume | OFF, 10% - 100% (10% steps) |
| CRT Effect | ON / OFF |
| Frameskip | None, Low, Medium, High, Extreme |
| Mouse Port | Gamepad 1 / Gamepad 2 (hidden when no mouse is connected) |
| Gamepad 1 | Any, NES 1, NES 2, USB 1, USB 2, Keyboard |
| Gamepad 2 | NES 1, NES 2, USB 1, USB 2, Keyboard, Disabled |
| Button Mapping | Per-input button remap + Clean USB Cache (re-arm wizard) |
| Video Settings | BG1-4, Sprites, Transparency, HDMA toggles |
| Audio Settings | Echo, Interpolation toggles |
| Restart Game | Reload current ROM from SD |
| Change ROM | Return to ROM browser |
| Back to Game | Resume gameplay |
Settings are saved to snes/settings.ini and persist across reboots.
- Install the Raspberry Pi Pico SDK (version 2.0+)
- Set environment variable:
export PICO_SDK_PATH=/path/to/pico-sdk - Install ARM GCC toolchain
git clone https://github.com/rh1tech/frank-snes.git
cd frank-snes
./build.sh M2 # or M1 for M1 layoutOutput: build/frank-snes.uf2
./release.shBuilds both M1 and M2 variants with USB HID enabled. Output files in release/:
frank-snes_m1_A_BB.uf2frank-snes_m2_A_BB.uf2
Hold BOOTSEL and plug in the Pico 2 via USB, then copy the .uf2 file to the mounted drive. Or use picotool:
picotool load build/frank-snes.uf2Make sure your board matches the correct firmware variant (M1 or M2). The HDMI pins are different between layouts.
Make sure the metadata files are in the correct directory structure on the SD card. See Game Metadata above.
This is normal - CRC32 checksums are being computed for all ROMs. Subsequent boots will be fast thanks to the cache file.
Delete snes/settings.ini from the SD card to restore defaults.
Power-cycle with the pad connected and run through the on-screen A / B calibration wizard that appears on first connect. If you already dismissed it or want to redo it, open Settings → Button Mapping → Clean USB Cache — this removes the learned snes/gamepads/gamepad_VVVV_PPPP.txt file and re-arms the wizard on next connect.
Open the settings menu and confirm Mouse Port is set to the controller port the game expects (most SNES mouse titles use port 1). The Mouse Port entry is hidden until a PS/2 or USB mouse is detected.
NES vs. SNES pad detection is sticky per port and only flips from NES to SNES once SNES-only bits are seen. If you swap pads on the same port, power-cycle the device.
Copyright (c) 2026 Mikhail Matveev <xtreme@rh1.tech>
Original FRANK SNES code is licensed under the GNU General Public License v3.0. The Snes9x emulator core has its own license that restricts commercial use. See LICENSE for full details.
| Project | Author(s) | License | Used For |
|---|---|---|---|
| Snes9x / snes9x2010 | Gary Henderson, Jerremy Koot, et al. | Snes9x freeware | SNES emulation core |
| pico-snes | xrip | — | Initial RP2350 port |
| FatFS | ChaN | Custom permissive | FAT32 filesystem |
| pico_fatfs_test | Elehobica | BSD-2-Clause | SD card PIO-SPI driver |
| PS/2 keyboard driver | mrmltr | GPL-2.0 | PS/2 keyboard PIO driver |
| TinyUSB | Ha Thach | MIT | USB HID host driver |
| Raspberry Pi Pico SDK | Raspberry Pi Foundation | BSD-3-Clause | Hardware abstraction layer |
Special thanks to:
- Gavin — SNES metadata and support
- Murmulator community — USB HID, HDMI, PSRAM, and audio drivers
Mikhail Matveev <xtreme@rh1.tech>