MonoSync Controller Firmware

MonoSync is a unified USB Gamepad + USB MIDI Controller platform built around the RP2040, supporting two hardware tiers: MonoSync Lite and MonoSync XL. This repository contains the firmware for both models, designed for modularity, stability, and cross-platform compatibility.

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Features

MonoSync Lite

• 8 Gamepad Buttons: UP, DOWN, LEFT, RIGHT, A, B, START, SELECT
• 4 Ultra-stable analog pots (MIDI CC output)
• USB Composite Device: HID Gamepad + MIDI
• Clean, compact hardware (RP2040)
• GPIO0 & GPIO1 reserved for expansion

MonoSync XL (Planned)

• All Lite features
• Additional buttons, rotary encoders, MIDI pads
• Internal clock, sequencer, arpeggiator, MIDI clock OUT
• 7-segment/OLED display for tempo, CC, mode
• EEPROM/FRAM storage for user settings
• Advanced transport and sync features

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Firmware Architecture

• input.c — GPIO, ADC acquisition, filtering
• engine.c — State change detection, HID & MIDI dispatch
• usb_gamepad.c — HID report generation
• usb_midi.c — MIDI stream I/O
• usb_descriptors.c — USB composite HID+MIDI descriptors
• tusb_config.h — TinyUSB configuration

Key Firmware Features

• 32× oversampling, EMA smoothing, hysteresis for analog inputs
• Change-only sending for HID and MIDI (no spam)
• D-pad mapped to X/Y axes, A/B/SELECT/START to HID buttons
• MIDI CC mapping for each pot (Lite), extended controls for XL

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Hardware Overview

• RP2040 module-based
• Low-noise analog section (ferrite bead, RC filtering, decoupling)
• THT tactile switches and pots
• Optional headers for expansion
• USB powered (no battery in Lite)

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Supported Platforms

• Android, PC, Mac, Retro handhelds, Raspberry Pi
• Tested on M8 Headless and mobile DAWs

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Getting Started

1. Clone this repository
2. Build the firmware using the provided CMake configuration
3. Flash to RP2040 using your preferred method (UF2, OpenOCD, etc.)
4. Connect via USB — device will enumerate as HID Gamepad + MIDI

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Project Roadmap

• MonoSync Lite firmware and PCB v1.0
• MonoSync XL schematic/layout
• Encoder support in firmware
• Clock/arp/sequencer engine
• FRAM/EEPROM memory map
• Enclosure and panel design
• Expanded documentation

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Project Preview

▶️ Demo Video

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License

Open hardware and firmware. See LICENSE for details.

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Contributing

Contributions, issues, and feature requests are welcome! Please see the documentation and roadmap for guidance.

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