EuroPi-Go

EuroPi-Go

An alternative firmware for the EuroPi Eurorack module, written in Go and compiled for the Raspberry Pi Pico with TinyGo. The official EuroPi firmware is written in MicroPython; EuroPi-Go explores what the same hardware feels like with a compiled language — faster execution, a real type system, and a familiar Go toolchain.

The module is a self-build Eurorack module that puts a Raspberry Pi Pico behind a small OLED display, two knobs, two buttons and a handful of CV inputs and outputs. EuroPi-Go boots into a menu of apps and lets you run them on the real hardware or in a mock on your desktop.

A stalled project, now worth re-checking

Development stalled on a TinyGo runtime bug: the Pico would freeze when using channels, goroutines and timers together — exactly the combination this firmware relies on. That issue was closed as completed on 23 September 2026, so it’s likely worth revisiting the project now.

Apps

The firmware ships a menu of small apps, several of them ports of ideas from the Python EuroPi scripts:

• Clock — a clock generator.
• Trigger Gate 2 — a trigger-to-gate converter (see the Python Trigger to Gate script).
• Trigger Mirror — mirrors an incoming trigger to an output.
• Pixels 4 — a four-pixel display toy.
• Font Display and Hello World — display demos.
• Menu Fun — a menu demo.
• Diagnostic — hardware diagnostics.

Display and fonts

Text is written to the display with a small drawing API. The default is three lines, or you can build with -tags lotslines for four lines (on the 32-pixel-high display the lines then sit flush against each other, so it’s a readability trade-off).

By default it uses the same custom 8x8 font as the original MicroPython firmware. A -tags tinyfont build switches to the TinyGo font library, which doesn’t look as good but can be pointed at a range of fonts.

Mock mode

You don’t need the hardware to develop against it. A mock build simulates the display, knobs and buttons and runs as a normal Go program, optionally with a Bubble Tea terminal UI:

go run ./cmd/mock        # plain text display output, handy for testing
go run ./cmd/mock -tea   # interactive terminal UI

The mock also accepts -lotslines and -tinyfont flags to match the hardware build tags.

Building and flashing

Install TinyGo, then from the project directory:

go mod tidy
tinygo flash -target=pico --monitor ./cmd/pico

If flashing fails, unplug the Pico, re-run the command, and hold the reset button while reconnecting the USB cable. To just prove it compiles, use tinygo build -target=pico ./cmd/pico. The code is developed with a tinygo build tag in VSCode so intellisense matches the target; disable that tag when running the mock or the tests.

Testing

go test ./...

There are tests for the display and control packages, using the mock implementations.

Relationship to the other EuroPi projects

• EuroPi - Trigger to Gate — the Python script that converts triggers into gates, with gate delay and a clock mode.
• EuroPi - Utility Classes — the Scheduler, Hysteresis Mitigation and Knob Pass Through classes for Python EuroPi scripts.

Technologies

Code: github.com/abulka/europi-go · MIT