Gio

gio

A 2 HP Eurorack generative arpeggiator module built around the Seeed XIAO RP2350. Produces scale-quantised V/Oct pitch CV and gate outputs driven by a probability-layered generative engine. Open-source hardware and firmware.

Spiritual successor to funkfinger/xiao-ra4m1-arp, ported to the RP2350 with an encoder + OLED UI and an external I2C DAC (MCP4725) in place of the RA4M1's onboard DAC.

Status

Planning / pre-prototype. No hardware fabricated yet; no firmware released. See docs/decisions.md for the bring-up plan and docs/stories/ for the story-driven development backlog.

Repo layout

gio/
├── firmware/arp/     PlatformIO project for the arpeggiator firmware
├── hardware/         KiCad project — populated post-breadboard validation
├── docs/             Specification, decisions, user stories
└── CHANGELOG.md      Keep a Changelog format; updated on every commit

Documentation

• Specification — hardware spec, firmware architecture, BOM, calibration
• Decisions — tooling, scope, workflow, licensing, versioning
• Stories — user-story-driven development backlog

Toolchain

• Firmware: PlatformIO with the earlephilhower Arduino-Pico platform (board = seeed_xiao_rp2350)
• Tests: host-side unit tests via pio test -e native for pure-logic modules (scales, arp, tempo). HAL is bench-verified.
• Hardware: KiCad (project deferred — see decisions)
• CI: GitHub Actions runs host tests on push and PR

Versioning

• Firmware: Semantic Versioning, scoped tags per firmware: arp/v0.1.0
• Hardware: Rev N.M notation, silkscreened on the PCB
• Docs: unversioned; history lives in git log

See decisions §12 for full rules.

Licensing