PicoVintageSynthCollection

Nine vintage synthesizer emulations for the RP2350, built from one shared codebase. Same board, same core, one firmware image per instrument.

Demo

▶ Demo video on YouTube

Instruments

Folder	Instrument	Binary
instruments/PicoFaceYC	Yamaha reface YC (drawbar organ)	PicoFaceYC.uf2
instruments/PicoFaceCP	Yamaha reface CP (electric piano, mdaEPiano)	PicoFaceCP.uf2
instruments/PicoFaceDX	Yamaha reface DX (4-operator FM)	PicoFaceDX.uf2
instruments/PicoFaceRD	Roland RD / MKS-20 (sample piano)	PicoFaceRD.uf2
instruments/PicoFaceJ6	Roland Juno-6	PicoFaceJ6.uf2
instruments/PicoFaceMD	Minimoog Model D	PicoFaceMD.uf2
instruments/PicoFaceSM	ARP/Eminent Solina String Ensemble	PicoFaceSM.uf2
instruments/PicoFaceOB	Oberheim OB-X (engine ported from OB-Xf)	PicoFaceOB.uf2
instruments/PicoFaceJV	Roland JV-880 (native engine over the original PCM data)	local build only

The JV-880 is the one exception to "download and flash": it only builds where a JV-880 ROM set is present, and the ROMs are not distributable, so it is not in the release binaries. Without them the configure step skips it and the eight above are unaffected. It runs on the hardware, and -DPICOFACEJV_4MB=ON fits it on a base 4 MB Pico 2.

Hardware

• RP2350
• Board sparkfun_promicro_rp2350
• I2S audio
• 128x64 OLED over I2C
• Three rotary encoders with push buttons
• USB MIDI and DIN MIDI

The pin map is the same for every instrument and lives in core/include/project_config.h.

Building

git clone --recurse-submodules https://github.com/Michi71/PicoVintageSynthCollection.git
cd PicoVintageSynthCollection
cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
cmake --build build

The artifacts are then in build/<instrument>.uf2.

Building a single instrument:

cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release -DPICOFACE_INSTRUMENTS_FILTER=PicoFaceMD
cmake --build build

Repository layout

core/            shared runtime: audio pipeline, hardware, USB/DIN MIDI, GUI, persistence
cmake/           picoface_add_instrument() and the SDK import helpers
lib/             third-party static libraries (audio, encoder, u8g2) and the SDK submodules
instruments/     one folder per instrument: instrument.cmake, src/, include/, doc/, README.md
tools/           host-side tools; not part of any firmware image
docs/            documentation shared by all instruments
img/             photos of the prototype hardware

Documentation

Shared:

• Architecture - how core and instruments fit together, and why
• Adding an instrument - the three steps needed
• Host tools

Per instrument, under instruments/<name>/doc/: MIDI implementation charts, persistence formats, preset tables and the engineering logs of the individual ports. The per-instrument README links them.

Manufacturer manuals and service documentation are not part of this repository. Where an emulation follows a specific manual or schematic, the instrument's README names the document so it can be obtained separately.

Status

All nine instruments build from a single configure run, each with its own USB PID, and all nine run on the hardware. Eight are in the release binaries; the JV-880 needs a local ROM set, as above. Open points are listed in docs/ARCHITECTURE.md, section 8.

License

GNU General Public License, version 3 or later - see LICENSE. Copyright (C) 2026 Michi71.

That is what every one of the seven single-instrument repositories this collection was assembled from already declared: all seven shipped the identical GPL-3 licence text, and every instrument README states GPL-3. It is also the lowest common denominator of what the engines are built on. Where an instrument derives from someone else's work:

Part	Upstream it derives from	That upstream's license
core, cmake, tools	own work	-
PicoFaceYC	OpenB3 / BeatrixCPP - tone generation concepts only, no code	AGPL-3.0 upstream, does not reach here; see below
PicoFaceCP	mda-EPiano (engine, in tree)	GPL-3.0-or-later
PicoFaceDX	an ESP32 reface DX emulation (engine)	see that project
PicoFaceRD	giulioz/rdpiano + MAME (reference emulator, host side only)	GPL
PicoFaceJ6	junox (patch table, parameter scaling)	GPL-3
PicoFaceMD	BelaMiniMoogEmulation (ladder filter)	stated by its author to be under no copyright
PicoFaceSM	string-machine (DSP models)	Boost Software License 1.0
PicoFaceOB	OB-Xf (engine)	GPL-3.0-or-later

instruments/PicoFaceOB/ additionally carries its own LICENSE, identical in text, because that instrument's engine is a direct port of OB-Xf and its files keep the upstream copyright headers. Every instrument builds into its own binary, so a stricter licence on one of them stays confined to that binary.

Source files carry a two-line SPDX header rather than the full notice, to keep it out of the way of the code. Three kinds exist:

• own work: GPL-3.0-or-later plus the copyright line;
• ported trees (instruments/PicoFaceDX/include/dx_engine/, instruments/PicoFaceRD/**/rd_engine/): the licence line plus a note that copyright is shared with the upstream authors - no sole claim is made there;
• upstream files (instruments/PicoFaceOB/include/obxf/, CP's mdaEPiano.*, MAME's mame_utils.h and mcu_ops.h, the SDK-derived usb_descriptors.c, get_serial.* and tusb_config.h): untouched, they keep the header they came with. The last four are MIT and BSD-3-Clause, not GPL.

On PicoFaceYC and the AGPL. OpenB3 / BeatrixCPP, whose tone generation concepts the YC drawbar engine follows, is AGPL-3.0 - stricter than GPL-3, and not something that can be dropped by relicensing. It does not apply here: the engine under instruments/PicoFaceYC/include/yc_engine/ was written for this project and contains no upstream code, which is why no file there carries an upstream copyright header. Copyright covers the expression, not the concepts, so GPL-3 is the right licence for it.