Roland MT-32 emulation

Copperline includes built-in Roland MT-32 emulation via mt32-rs, a Rust port of Munt’s mt32emu. Emulated MIDI audio is mixed alongside the Amiga’s native four-channel Paula output.

An interactive virtual front panel can be displayed beneath the video output.

ROM requirements¶

To use MT-32 emulation, you must provide two ROM images:

Control ROM (e.g., v1.07 or v2.07)
PCM ROM (sample data)

Supported modules include MT-32 (revisions 1 and 2), CM-32L, LAPC-I, and CM-32LN.

Example ROM hashes¶

Filename	Version	SHA-1 Hash
`mt32_ctrl_2_07.rom`	v2.07	`47b52adefedaec475c925e54340e37673c11707c`
`MT32_CONTROL.ROM`	v1.07	`b083518fffb7f66b03c23b7eb4f868e62dc5a987`
`MT32_PCM.ROM`	All	`f6b1eebc4b2d200ec6d3d21d51325d5b48c60252`

ROMs are verified by size and SHA-1 checksum upon loading.

Configuration¶

In the launcher:

Navigate to I/O Ports -> Serial Port.
Set Device / Mode to MIDI.
Set MIDI output to MT-32.
Select paths for Control ROM and PCM ROM.
Optionally enable Front panel and select an LCD display style.

In copperline.toml:

[serial]
mode = "midi"
midi_out = "mt32"
mt32_control_rom = "~/Amiga/MT32_CONTROL.ROM"
mt32_pcm_rom = "~/Amiga/MT32_PCM.ROM"
mt32_panel = true          # Show front panel (default: false)
mt32_lcd = "mt32"          # Display style: mt32, superjv, sseries, or oled

Command-line usage:

./target/release/copperline --model A1200 KICK31.ROM \
  --midi-out mt32 \
  --mt32-control-rom MT32_CONTROL.ROM \
  --mt32-pcm-rom MT32_PCM.ROM \
  --mt32-panel

`[serial]` configuration keys¶

Key	Values	Description
`midi_out`	`"mt32"`	Route serial MIDI output to built-in MT-32
`midi_in`	`"mt32"`	Wire MT-32 MIDI OUT back to serial input
`mt32_control_rom`	File path	Path to Control ROM image
`mt32_pcm_rom`	File path	Path to PCM ROM image
`mt32_panel`	`true` / `false`	Display virtual front panel (default: `false`)
`mt32_lcd`	`"mt32"`, `"superjv"`, `"sseries"`, `"oled"`	LCD appearance style (default: `"mt32"`)

Patch editors and librarians¶

Software such as patch editors and librarians (e.g., Caged Artist MT-32 Editor) send SysEx requests and expect responses. Set midi_in = "mt32" to route the virtual synthesizer’s MIDI output back into the Amiga’s serial port.

Virtual front panel¶

When mt32_panel = true is set, a reproduction of the MT-32 hardware panel is shown below the video output:

Left click: Press a button.
Right click: Latch/hold a button down (used for multi-button combinations).

Panel controls¶

Control	Function
PART 1-5, PART R	Select part to configure
SOUND GROUP	Cycle sound group (Preset A, Preset B, Memory, Rhythm)
SOUND	Select patch number (0-63)
VOLUME	Adjust volume for selected part (0-100)
MASTER VOLUME	Adjust overall synthesizer output level
Dial	Adjust parameter values (click or drag)
POWER	Power cycle the synthesizer engine

Multi-button combinations (Powered on)¶

Hold MASTER VOLUME (right-click), then click the corresponding button:

Combination	Function
`MASTER VOLUME` + `GROUP`	Adjust master tuning (427.5 to 452.6 Hz)
`MASTER VOLUME` + `VOLUME`	Select reverb mode (0-3)
`MASTER VOLUME` + `SOUND`	Set MIDI device unit number
`MASTER VOLUME` + `PART 1, 2, 3`	Select parts 6, 7, and 8
`MASTER VOLUME` + `PART 4`	Overflow assign mode (confirm with `PART 1`)
`MASTER VOLUME` + `PART 5`	Remap parts 1-8 to MIDI channels 1-8 (confirm with `PART 1`)
`MASTER VOLUME` + `PART R`	System master reset (confirm with `PART 1`)

Startup combinations (Power off)¶

With power off, right-click button combination and click POWER:

Combination	Function
`MASTER VOLUME` + `POWER`	Built-in demo sequence (requires v2.x ROM)
`1` + `3` + `MASTER VOLUME` + `POWER`	ROM test / firmware version display

LCD display styles¶

Value	Appearance	Preview
`mt32`	Classic 1987 green-backlit LCD
`superjv`	Orange-backlit display
`sseries`	Fluorescent display styling
`oled`	High-contrast white OLED styling

Runtime controls¶

In an active emulation window, the top menu bar under Serial Port allows switching MIDI output between MT-32, Coppersynth, or host MIDI ports without restarting emulation.

ROM images can be loaded or changed dynamically from the Serial Port -> MT-32 menu.

Building without MT-32 support¶

To exclude MT-32 support when compiling from source:

cargo build --release --no-default-features \
  --features "midi,frontend,wasm-boards,control,ctl-bin,net-nat,net-bridge,fluxbridge,coppersynth,cpu-jit,profile-stats,game-library,mhi,cd-mp3"

Troubleshooting¶

MT-32: missing ROM(s): One or both ROM paths are missing or invalid.
MT-32: invalid ROM(s): Provided files failed SHA-1 verification.
Diagnostic logging: Set COPPERLINE_MT32_DEBUG=1 or COPPERLINE_MIDI_DEBUG=1 in the environment to log MIDI message flow.