DaisySP Patch.Init Eurorack Firmware

Custom firmware for the Patch.Init Eurorack module using DaisySP DSP library.

Overview

This project provides a custom firmware implementation for the Electro-Smith Patch.Init Eurorack module. The Patch.Init is a versatile eurorack module featuring:

• 2x CV inputs (±5V)
• 2x CV outputs (±5V)
• 2x audio inputs
• 2x audio outputs
• Multiple GPIO pins for buttons, LEDs, and encoders
• STM32H7 microcontroller with floating-point unit

DuoPulse v5: 2-Voice Algorithmic Drum Sequencer

DuoPulse v5 is an opinionated 2-voice percussion sequencer designed for electronic music from club-ready techno to experimental IDM. Version 5 features zero shift layers - every parameter is directly accessible through 8 knobs across two modes.

Core Design Philosophy

1. Zero shift layers: Every parameter directly accessible
2. CV law: CV1-4 always modulate performance parameters regardless of mode
3. Knob pairing: Related functions across Performance/Config modes
4. Deterministic variation: Same settings + seed = identical output

Control Layout

Performance Mode (Switch UP)

Knob	Parameter	0%	100%
K1	ENERGY	Sparse	Busy
K2	SHAPE	Stable (euclidean)	Wild (weighted random)
K3	AXIS X	Grounded (downbeats)	Floating (offbeats)
K4	AXIS Y	Simple	Complex

Config Mode (Switch DOWN)

Knob	Parameter	0%	100%
K1	CLOCK DIV	÷4 (slow)	×4 (fast)
K2	SWING	Straight	Heavy swing
K3	DRIFT	Locked (same each phrase)	Evolving
K4	ACCENT	Flat (all hits equal)	Dynamic (ghosts to accents)

Key Features

SHAPE Zones: Three-way pattern character blending

• 0-30% STABLE: Humanized euclidean, techno, four-on-floor
• 30-70% SYNCOPATED: Funk, displaced, tension
• 70-100% WILD: IDM, chaos, weighted random

Voice Relationship (COMPLEMENT): Voice 2 (shimmer) fills gaps in Voice 1 (anchor) pattern. DRIFT controls placement variation.

ACCENT Velocity: Position-aware dynamics from ghost notes to accents based on metric weight.

AUX Output: Fill Gate (default) or secret Hat Burst mode via Hold+Switch gesture.

CV Inputs (Always Modulate Performance Params)

CV	Modulates	Range
CV 1	ENERGY	±50%
CV 2	SHAPE	±50%
CV 3	AXIS X	±50%
CV 4	AXIS Y	±50%

Power-On Behavior

Fresh-start boot: All settings reset to musical defaults

• Performance knobs read from hardware immediately
• ENERGY=50%, SHAPE=30%, AXIS X/Y=50%
• CLOCK DIV=×1, SWING=50%, DRIFT=0%, ACCENT=50%
• Nothing persists across power cycles

See docs/specs/ for the complete specification.

Prerequisites

• Hardware: Electro-Smith Patch.Init Eurorack module
• Software:
  • ARM GCC toolchain (for STM32)
  • arm-none-eabi-gcc compiler
  • make build system
  • dfu-util for firmware deployment (or STM32CubeProgrammer)
  • For testing: Catch2 testing framework (optional)
• DaisySP: Included as a git submodule

Installing Dependencies

macOS (using Homebrew):

brew install arm-none-eabi-gcc dfu-util

Linux (Debian/Ubuntu):

sudo apt-get update
sudo apt-get install gcc-arm-none-eabi dfu-util make

Catch2 (for unit testing):

# Option 1: Install system-wide (recommended)
git clone https://github.com/catchorg/Catch2.git
cd Catch2
cmake -Bbuild -H. -DBUILD_TESTING=OFF
sudo cmake --build build/ --target install

# Option 2: Use package manager
# macOS: brew install catch2
# Linux: sudo apt-get install catch2 (if available)

Project Structure

.
├── DaisySP/              # DaisySP library (git submodule)
├── src/                  # Source files
│   ├── main.cpp         # Main firmware entry point
│   └── ...
├── inc/                  # Header files
│   └── ...
├── tests/                # Unit tests
│   ├── test_main.cpp    # Test runner
│   └── ...
├── Makefile             # Build configuration
├── setup.sh             # Setup script for initial configuration
├── .cursor/             # Cursor IDE rules
│   └── rules
└── README.md            # This file

Build Instructions

Initial Setup

Quick Setup (recommended):

# Clone the repository
git clone --recursive https://github.com/yourusername/duopulse.git
cd duopulse

# Run setup script (initializes submodules and builds DaisySP)
./setup.sh

# Build the firmware
make

Manual Setup:

1. Clone the repository (including submodules):

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

   If you've already cloned without submodules:

   git submodule update --init --recursive

2. Build DaisySP library:

   cd DaisySP
   make
   cd ..

3. Build the firmware:

   make

Build Targets

• make or make all - Build the firmware
• make clean - Remove build artifacts
• make rebuild - Clean and rebuild
• make test - Build and run unit tests
• make program - Flash firmware to Patch.Init module (requires DFU mode)
• make daisy-update - Update DaisySP submodule to latest version

Build Configuration

The Makefile supports the following variables:

• DAISYSP_PATH - Path to DaisySP (default: ./DaisySP)
• BUILD_DIR - Build output directory (default: build)
• TARGET - Target board (default: patch)
• DEBUG - Enable debug symbols (set DEBUG=1)

Example:

make DEBUG=1 BUILD_DIR=debug_build

Test Instructions

Running Unit Tests

The project includes a unit test framework using Catch2:

1. Run all tests:

   make test

2. Run specific test:

   ./build/test_runner [test_name]

3. Run tests with verbose output:

   ./build/test_runner --success

Writing Tests

Tests are located in the tests/ directory. Each test file should:

• Include the Catch2 header: #include <catch2/catch.hpp>
• Use TEST_CASE() macro for test cases
• Use REQUIRE() or CHECK() for assertions

Example:

#include <catch2/catch.hpp>
#include "../src/my_module.h"

TEST_CASE("MyModule processes audio correctly")
{
    MyModule module;
    module.Init(48000.0f);
    
    float input = 0.5f;
    float output = module.Process(input);
    
    REQUIRE(output >= -1.0f);
    REQUIRE(output <= 1.0f);
}

Test Coverage

To generate test coverage reports:

make test-coverage

This requires gcov and lcov to be installed.

Deploy Instructions

Preparing the Module

1. Enter DFU (Device Firmware Update) mode:

   • Power off the module
   • Hold the BOOT button (if available) or use the DFU jumper
   • Power on the module while holding BOOT
   • Release BOOT button
   • The module should now be in DFU mode

2. Verify DFU mode:

   dfu-util --list

   You should see the STM32 device listed.

Flashing Firmware

Method 1: Using Makefile (recommended)

make program

Method 2: Using dfu-util directly

dfu-util -a 0 -s 0x08000000:leave -D build/patch-init-firmware.bin

Method 3: Using STM32CubeProgrammer

1. Open STM32CubeProgrammer
2. Select "USB" connection
3. Connect to the device
4. Load the .bin or .hex file from build/
5. Click "Download"

Post-Flash

After flashing:

1. Power cycle the module (or use :leave flag with dfu-util)
2. The module should boot with the new firmware
3. Test audio and CV I/O to verify functionality

Troubleshooting

• Device not found: Ensure module is in DFU mode and USB cable is connected
• Permission denied: Add udev rules for STM32 DFU devices (Linux) or run with sudo
• Flash fails: Verify module is in DFU mode and try resetting the module

Upgrading DaisySP

Update to Latest Version

1. Navigate to DaisySP directory:

   cd DaisySP

2. Fetch and checkout latest version:

   git fetch origin
   git checkout master  # or specific tag/commit
   git pull origin master

3. Rebuild DaisySP:

   make clean
   make

4. Return to project root and rebuild:

   cd ..
   make clean
   make

Update to Specific Version/Tag

cd DaisySP
git fetch --tags
git checkout v1.0.0  # Replace with desired version
make clean
make
cd ..
make clean
make

Update Submodule Reference

After updating DaisySP, commit the submodule reference:

git add DaisySP
git commit -m "Update DaisySP to version X.X.X"

Checking Current Version

cd DaisySP
git describe --tags
cd ..

Development Workflow

1. Create a feature branch:

   git checkout -b feature/my-feature

2. Make changes and test:

   make clean
   make
   make test

3. Flash and test on hardware:

   make program

4. Commit changes:

   git add .
   git commit -m "Description of changes"

5. Push and create pull request

Hardware Configuration

Patch.Init Pin Assignments

Refer to the Patch.Init documentation for specific pin assignments. Common configurations:

• CV Inputs: ADC channels 0-1
• CV Outputs: DAC channels 0-1
• Audio Inputs: I2S/SAI interface
• Audio Outputs: I2S/SAI interface
• GPIO: Configurable via daisy::GPIO

Sample Rate

Default sample rate: 48kHz

To change:

patch.SetAudioSampleRate(daisy::SaiHandle::Config::SampleRate::SAI_96KHZ);

Block Size

Default block size: 4 samples

To change:

patch.SetAudioBlockSize(8);

Contributing

1. Follow the coding standards in .cursor/rules
2. Write unit tests for new features
3. Update documentation as needed
4. Test on hardware before submitting PR

License

[Specify your license here]

Resources

• DaisySP Documentation
• Daisy Hardware Documentation
• Patch.Init Module Info
• STM32 Documentation

Troubleshooting

Build Issues

• Missing toolchain: Install ARM GCC toolchain
• DaisySP not found: Run git submodule update --init --recursive
• Linker errors: Ensure DaisySP is built (cd DaisySP && make)

Runtime Issues

• No audio output: Check audio callback registration and hardware connections
• CV not working: Verify ADC/DAC configuration and pin assignments
• Module crashes: Check for stack overflow, uninitialized variables, or division by zero

Debugging

Enable debug output:

make DEBUG=1

Use a debugger (OpenOCD + GDB) for hardware debugging:

make debug

Runtime Logging

The firmware includes a USB serial logging system for debugging without a hardware debugger.

Viewing Log Output:

# macOS/Linux - using screen
screen /dev/tty.usbmodem* 115200

# Alternative - using make target (saves to /tmp)
make listen

# Exit screen: Ctrl-A then \ then y

Log Levels:

• TRACE: Verbose debugging
• DEBUG: Development info (mode changes, events)
• INFO: Normal operation (boot, config)
• WARN: Warnings
• ERROR: Critical issues

Configuration:

Adjust log levels in Makefile:

# Development: DEBUG+ logs, default INFO
CXXFLAGS += -DLOG_COMPILETIME_LEVEL=1
CXXFLAGS += -DLOG_DEFAULT_LEVEL=2

# Release: WARN/ERROR only
CXXFLAGS += -DLOG_COMPILETIME_LEVEL=3
CXXFLAGS += -DLOG_DEFAULT_LEVEL=3

See CLAUDE.md for complete logging documentation.

Support

For issues and questions:

• Open an issue on GitHub
• Check the DaisySP documentation
• Visit the Daisy Forum