GUI2C (proof of concept)
GUI2C is the POC of an open high-level protocol that allows Eurorack modules to send visual information to dedicated display modules over I2C.
Key Features
- Offloads display rendering from the module
The module only sends compact high-level display commands. The display module handles rendering locally, reducing CPU load, firmware complexity, and display-driver dependencies on the client side. Modules can stay focused on sound generation, control, and interaction, while display-specific hardware and rendering logic live in the display module. - Reusable display hardware
A dedicated display module can serve multiple products or systems instead of being tied permanently to one module design. Users can decide which module uses which display. A display can show one module today and another tomorrow, depending on the patch and the system setup. - Manufacturer-independent compatibility
GUI2C is designed so display modules and Eurorack modules from different manufacturers can work together through a shared protocol. - Open standard
The specification, documentation, libraries, firmware, and demo code are freely available so any manufacturer or developer can implement GUI2C-compatible hardware and software. - Community-driven development
GUI2C is intended to evolve cooperatively. We invite manufacturers, developers, and users to test it, improve it, extend it, and help shape future versions. - Future-ready multi-view concept
GUI2C is being designed with future split-screen and multi-view display scenarios in mind, where one display module could potentially serve different visual areas or clients.
The GUI2C specification, documentation, client library, server firmware, and demo code are freely available. We invite Eurorack manufacturers, developers, and curious builders to implement GUI2C-compatible modules, test the protocol, suggest improvements, and participate in its further development.
GUI2C is not meant to be a closed product feature. It is meant to become a shared language for Eurorack displays.
Links
- GUI2C Specification
https://github.com/any-frequency/gui2c
Protocol specification, architecture notes, and documentation. - GUI2C Client Library for RP2040/RP2350
https://github.com/any-frequency/gui2c_client_library_rp2350_rp2040
C/Pico-SDK client library for Eurorack modules that want to drive GUI2C displays. - GUI2C ILI9488 Display Server
https://github.com/any-frequency/gui2c_server_ili9488
Pico-based display-server firmware and rendering stack for ILI9488 display modules. - GUI2C Demo Client
https://github.com/any-frequency/gui2c_demo_client
Example client firmware showing text, values, bars, rings, and waveform graphics on a GUI2C display.




