Nuked-SC55

Notice: development and maintaining of this emulator has stopped

Thanks to everyone who was using and enjoying it! You can use one of awesome forks like the one from jcmoyer.

This was my dream project for about a decade (since I got SC-55 unit in 2014) and culmination of my reverse-engineering works, and I'm glad I was able to pull it through.

Unfortunately this project also caused me pretty severe burnout, so I decided to take a break from project back in 2024. This coupled with pressure to relicense the project and usage info/code from my code against my will/without permission or outright license violations, made me very hard to pick it back.

So in 2026 decision was made to relicense the project to GPL2, archive the repository and completely cease any further work. Sorry if I disappointed anyone with this decision, but doing so is going be better to my mental health.

Nuked SC-55

Roland SC-55 emulator, by nukeykt.

Supported models:

• SC-55mk2/SC-155mk2 (v1.01 firmware is confirmed to work)
• SC-55mk1 (v1.0/v1.21/v2.0 firmwares are confirmed to work)
• CM-300/SCC-1 (v1.10/v1.20 firmwares are confirmed to work)
• SCC-1A
• SC-55st (v1.01)
• JV-880 (v1.0.0/v1.0.1)
• SCB-55/RLP-3194
• RLP-3237
• SC-155

Special thanks:

• John McMaster: SC-55 PCM chip decap.
• org/ogamespec: deroute tool.
• SDL team.
• Wohlstand: linux/macos port.
• mattw.
• HardWareMan.
• giulioz: JV-880 support
• Cloudschatze.
• NikitaLita.
• Karmeck.

License

Nuked SC-55 can be distributed and used under the GPL v2.0 or later license. See LICENSE file for the details.

Status

3 ICs are needed to be emulated:

• Roland PCM chip
• Hitachi H8/532 MCU
• Mitsubishi M37450M2 MCU

MCUs are emulated using info from their datasheets. PCM chip info is derived from analyzing decapped chip.

PCM chip tracing progress

MCU emulation progress

Install

Put firmware image into the same folder as Nuked SC-55. Files should be names as such:

…

Additional info

• Nuked SC-55 will listen to the specified MIDI IN port (default is port 0). Use -p: command line argument to specify port number. To use it with the other applications use external MIDI pipe software (e.g. loopMIDI).

• SC-55mk2/SC-55mk1 buttons are mapped as such (currently hardcoded):

Q -> POWER
W -> INST ALL
E -> INST MUTE
R -> PART L
T -> PART R
Y -> INST L
U -> INST R
I -> KEY SHIFT L
O -> KEY SHIFT R
P -> LEVEL L
LEFTBRACKET  -> LEVEL R
A -> MIDI CH L
S -> MIDI CH R
D -> PAN L
F -> PAN R
G -> REVERB L
H -> REVERB R
J -> CHORUS L
K -> CHORUS R
LEFT -> PART L
RIGHT -> PART R

• JV-880 buttons are mapped as such (currently hardcoded):

P -> PREVIEW
LEFT -> CURSOR L
RIGHT -> CURSOR R
TAB -> DATA
Q -> TONE_SELECT
A -> PATCH_PERFORM
W -> EDIT
E -> SYSTEM
R -> RHYTHM
T -> UTILITY
S -> MUTE
D -> MONITOR
F -> COMPARE
G -> ENTER
COMMA -> ENCODER L
PERIOD -> ENCODER R

• -mk2, -st, -mk1, -cm300, -jv880, -scb55, -rlp3237, -sc155 and -sc155mk2 command line arguments can be used to specify rom set. If no model is specified emulator will try to autodetect rom set (based on file names).

• Due to a bug in the SC-55mk2's firmware, some parameters don't reset properly on startup. Do GM, GS or MT-32 reset using buttons to fix this issue.

• SC-155 doesn't reset properly on startup (firmware bug?), use Init All option to workaround this issue.

• SC-155's additional buttons/sliders are not emulated at the moment. They will be emulated in the future after proper GUI is implemented.