Game Boy-inspired oscillators for KORG logue synthesizers (minilogue xd, prologue, and Nu:Tekt NTS-1 digital kit).

logue-boy is a collection of three custom oscillators that recreate the iconic sound chip characteristics of Nintendo's Game Boy handheld console. These oscillators are built using the KORG logue SDK and provide authentic 8-bit sound generation for modern synthesizers.

The Game Boy's sound hardware featured a simple but characterful audio processing unit with four sound channels. This project recreates three of those channels:

• Pulse Wave Channel with variable duty cycle
• Wave Channel with custom wavetables (inspired by Pokémon Gold/Silver)
• Noise Channel with configurable shift register

Emulates the Game Boy's pulse wave channels (channels 1 and 2) with selectable duty cycles.

Features:

• Four duty cycle options: 12.5%, 25%, 50%, and 75%
• Envelope-based attenuation effect for authentic sound shaping
• Perfect for classic chiptune leads and bass lines

Parameters:

• Shape: Selects duty cycle (12.5% / 25% / 50% / 75%)
• Shift+Shape: Controls attenuation depth (0-100%)

Recreates the Game Boy's noise channel (channel 4) using a Linear Feedback Shift Register (LFSR).

Features:

• 15-bit LFSR implementation matching Game Boy hardware
• Two noise modes: short (7-bit) and long (15-bit)
• Pitch tracking for tonal noise effects

Parameters:

• Shape: Switches between short mode (< 50%) and long mode (≥ 50%)

Technical Details:

• Uses XOR feedback between bits 0 and 1
• Short mode creates more periodic, tonal noise
• Long mode produces less repetitive, white-noise-like sound

Implements the Game Boy's wave channel (channel 3) with wavetables inspired by Pokémon Gold and Silver sound design.

Features:

• 10 unique 32-sample wavetables
• Variable bit resolution (1-16 bit) for lo-fi effects
• Linear interpolation between wavetable samples

Parameters:

• Shape: Selects wavetable (0-9)
• Shift+Shape: Controls bit resolution (1-16 bit)

Wavetables: Each wavetable contains 32 samples with 4-bit values (0-15), normalized to audio range [-1.0, 1.0]. The wavetables recreate various timbres used in Game Boy games, from smooth sine-like waves to more complex harmonic content.

All oscillators are compatible with:

• KORG minilogue xd
• KORG prologue
• KORG Nu:Tekt NTS-1 digital kit

1. KORG logue SDK: The repository includes the SDK as a git submodule in libs/logue-sdk/
2. GNU ARM Embedded Toolchain: Required for cross-compilation
3. GNU Make: For building the oscillators
4. logue-cli (optional): For validating built units

git clone --recursive https://github.com/yourusername/logue-boy.git
cd logue-boy

The logue SDK requires the GNU ARM Embedded Toolchain version 5.4 (5-2016-q3-update) for cross-compilation.

macOS:

cd libs/logue-sdk/tools/gcc
./get_gcc_osx.sh
cd ../../../..

Note: On Apple Silicon Macs, the Intel x86_64 toolchain will run via Rosetta 2.

Linux:

cd libs/logue-sdk/tools/gcc
./get_gcc_linux.sh
cd ../../../..

Windows (MSYS2):

cd libs/logue-sdk/tools/gcc
./get_gcc_msys.sh
cd ../../../..

The logue-cli tool is used for validating built unit files and can also load them onto your device.

macOS:

cd libs/logue-sdk/tools/logue-cli
./get_logue_cli_osx.sh
cd ../../../..

Linux:

cd libs/logue-sdk/tools/logue-cli
./get_logue_cli_linux.sh
cd ../../../..

Windows (MSYS2):

cd libs/logue-sdk/tools/logue-cli
./get_logue_cli_msys.sh
cd ../../../..

Option 1: Build all oscillators for all platforms

Use the provided build script to build all 3 oscillators for all 3 platforms (9 units total):

./tools/build.sh

This will build and validate all units. Each build outputs .mnlgxdunit, .prlgunit, or .ntkdigunit files depending on the platform.

Option 2: Build specific oscillators

Build individual oscillators by navigating to their platform-specific directories:

# Example: Build pulse oscillator for minilogue xd
cd osc/pulse/platform/minilogue-xd
make

# Validate the built unit (requires logue-cli)
make check

Available oscillators and platforms:

• Oscillators: pulse, noise, pokegold
• Platforms: minilogue-xd, prologue, nutekt-digital
• Path pattern: osc/{oscillator}/platform/{platform}/

Compiled oscillators generate platform-specific unit files:

• minilogue xd: .mnlgxdunit
• prologue: .prlgunit
• Nu:Tekt NTS-1: .ntkdigunit

These files can be loaded onto your KORG device using:

• KORG's official librarian software
• logue-cli tool (see Installation section below)

The project includes unit tests for each oscillator using Google Test framework.

1. Install Meson and Ninja build system:

pip3 install meson ninja

2. Setup and run tests:

meson setup builddir
meson test -C builddir

Or run individual tests:

./builddir/pulse_test
./builddir/noise_test
./builddir/pokegold_test

The project uses clang-tidy for static analysis and clang-format for code formatting.

Run clang-tidy on all source files:

./tools/lint.sh

Scope:

• Header files (.hpp) in the osc/ directory
• Test files are excluded (checked by unit tests instead)
• Implementation files (.cpp) are excluded (they require SDK headers that clang-tidy cannot locate)

Format all source files:

./tools/format.sh

Check if files are properly formatted (without making changes):

./tools/format.sh --check

Scope:

• All C++ source and header files (.cpp, .hpp) in the osc/ directory
• Test files are excluded

clang-tidy and clang-format on macOS:

brew install llvm

clang-tidy and clang-format on Ubuntu/Debian:

sudo apt install clang-tidy clang-format

Other systems: Install via your package manager or download from LLVM releases

• clang-tidy: Configured via .clang-tidy in the project root

  • Tuned for the logue SDK and embedded development
  • Enables bug detection, code quality, performance, and readability checks
  • Disables checks that conflict with SDK-specific naming conventions (e.g., OSC_INIT)
  • Allows necessary embedded programming patterns (pointer arithmetic, reinterpret_cast, etc.)

• clang-format: Configured via .clang-format in the project root

  • Based on Google C++ style guide
  • 2-space indentation
  • 100-character line limit
  • Consistent spacing and alignment rules

1. Build the oscillator for your platform
2. Use KORG's librarian software or logue-cli to transfer the .ntkdigunit file to your device
3. Select the oscillator from the user oscillator slots on your synthesizer

Refer to KORG's official documentation for detailed installation instructions.

The original Game Boy (DMG-01) featured a custom sound chip with four channels:

• Channel 1: Pulse wave with sweep
• Channel 2: Pulse wave
• Channel 3: Programmable wave
• Channel 4: Noise

This project focuses on recreating the core sound generation algorithms rather than the complete hardware behavior (envelopes, sweep effects, etc.), allowing these sounds to be controlled by the logue synthesizer's own envelope and modulation capabilities.

• Sample Rate: 48kHz (logue platform standard)
• Bit Depth: 32-bit floating point internal processing
• Wave Resolution: Matched to Game Boy specifications (4-bit wavetable samples, LFSR periods)
• Language: C++11

Copyright 2021 Akiomi Kamakura

Licensed under the Apache License, Version 2.0. See LICENSE for details.

Contributions are welcome! Please feel free to submit issues or pull requests.

• KORG logue SDK
• Game Boy Sound Hardware