An LSDJ-inspired music tracker for the Sega Master System and Game Gear, written in pure Z80 assembly. Make music on real hardware (via flashcart) or in an emulator, using just the D-pad and two buttons. Sound is the SN76489 PSG only — three square channels and noise — plus 4-bit PCM samples and drawn wavetables via the volume-register DAC trick, a built-in tempo-synced echo, and Game Gear stereo.

One source tree builds two ROMs:

• smsggdj.sms — Master System (full screen).
• smsggdj.gg — Game Gear / GGDJ (handheld screen, real stereo).

Prebuilt ROMs are on the Releases page — download smsggdj.sms / smsggdj.gg, flash to a cart or open in an emulator, no toolchain needed.

       L I T T L E - S C A L E

Needs WLA-DX (wla-z80 + wlalink) and Python 3. make run launches the bundled Emulicious (needs Java).

make          # build both: build/smsggdj.sms and build/smsggdj.gg
make run      # build both, launch the SMS ROM
make run-gg   # build both, launch the Game Gear ROM
make clean

Both ROMs boot to a blank song, ready to make music. The bundled demo song is loadable any time from the PROJECT screen (DEMO — a two-press confirm).

Drop a ROM on a flashcart (Master Everdrive etc.) or open it in an emulator, and press play.

• MANUAL.md — the user guide: controls, screens, writing a song, instruments, commands, live mode, saving, sync.
• tools/patcher.html — drop a built ROM + your own sounds in a browser, tune them (trim, gain, tanh, fades), audition the exact console sound, and download a ROM with your sample bank. No toolchain.
• tools/savetool.html — unpack songs from a .sav, assemble a cart image (pick 8/16/32 KB), or click a slot to view a song's notes, commands and instruments — in the browser.

• CLAUDE.md — build system, architecture, and the hard invariants (IRQ shadow registers, VDP write spacing, per-region tables).
• DESIGN.md — the design contract: hardware constraints, the song data model, the sound engine, the command set, the sample pool, sync, and the GGDJ build (§15). Read the relevant section before changing behaviour.
• SAVEFORMAT.md — the SRAM / .sav / .smdj save format.
• CHANGELOG.md — what changed, per version.
• HARDWARE.md — controller-port and Game Gear EXT pinouts, sync cabling, and the EXT paddle-PCB notes.

src/        Z80 assembly (main, vdp, input, psg, engine, sample, editor)
tools/      Python build tools + the browser apps:
              makefont / maketables / makedemo / makelogo  (build inputs)
              smsggdj_sample.py   WAV/pool -> sample bank
              savetool.py       song/.sav manager (CLI)
              patcher.html      browser sample patcher
              savetool.html     browser song/save manager
              palette.html      browser UI-palette recolourer
samples/    sample sources; samples/pool.bin (if present) is the baked bank
art/        the logo art

The committed samples/pool.bin is the production sample bank (tuned in the patcher) and is baked into every build. To build from raw recordings instead, delete samples/pool.bin and put WAVs in samples/ — make converts them. The pool is identical in both flavours, so one bank serves .sms and .gg.

MIT — see LICENSE. Use it, fork it, learn from it.

The bundled Emulicious emulator (tools/emulicious/, not in this repo) has its own license.

Made by little-scale.