sigroot FW LED Matrix Firmware

sigroot FW LED Matrix Firmware is an alternate firmware for the Framework Laptop 16 LED Matrix Input Module, written in Arduino/C++ by sigroot¹. It was created to address two limitations of the official FrameworkComputer/inputmodule-rs firmware: the inability to produce all 256 brightness levels and difficulty developing with the provided interface software¹.

The firmware supports full 256 brightness levels, achieves approximately 80 FPS full refresh rate, and includes a rich set of serial commands for animations and pixel-level control¹. It is recognized as a third-party firmware project by Framework's official InputModules documentation².

Background

The Framework LED Matrix is a 9×34 (306 LED) monochrome display panel driven by an RP2040 microcontroller and an IS31FL3741A LED controller²³. The official firmware, written in Rust, cannot produce all 256 brightness levels possible on the hardware¹. Sigroot's firmware solves this by allowing programs to write both PWM and scale values (as defined by the IS31FL3741A documentation) for single LEDs, all LEDs, or as a 9×34 pixel image¹.

Capabilities

Brightness Control

The firmware allows writing both PWM and scale values for¹:

• Single LEDs (per-pixel PWM and scale control)
• All LEDs at once
• Full 9×34 pixel grid images

A gamma correction function is included that changes the PWM brightness curve to be more visible across its entirety by the human eye³.

Animations

The firmware includes several built-in demo animations¹³:

Animation	Description
Boot-up animation	Custom startup animation1
Fire / Fireplace	Animated fire effect1
Diamond	Animated diamond pattern1
Spinning gear	Rotating gear animation1
Spinning ring	Rotating ring animation1
Test pattern	Cycles through all brightness levels on every pixel13

Performance

Metric	Value
Brightness levels	256 (full range)1
Refresh rate	~80 FPS (full grid refresh)1
LED controller	IS31FL3741A3
Grid size	9×34 (306 LEDs)1

Installation

The firmware can be installed via two methods¹:

UF2 File

Download the UF2 file from the repository, enter BOOTSEL mode on the LED Matrix module (DIP switch pin 2 ON), and copy the UF2 file to the mass storage device that appears¹.

Arduino IDE

Follow Joe Schroedl's instructions for reinstalling firmware to his RGB LED Matrix, but install the Arduino code from this repository instead. The Adafruit NeoPixel Library is not required¹.

Ecosystem

The firmware is part of a companion ecosystem of repositories by sigroot:

Repository	Description
FW_LED_Matrix_Firmware	The Arduino firmware itself1
FW_LED_Matrix_Interface	Rust library for interfacing between this firmware and other Rust programs14
FW_LED_Matrix_Board	Divides the 9×34 matrix into 3 smaller 9×11 "applets" with a language-agnostic interface15
FW_LED_Applet_Interface	Rust library for developing applets1

Applet System

The FW_LED_Matrix_Board server holds four total applets: Applet 0 is a 9×1 status bar across the top, and Applets 1–3 are 9×11 grids (each with an optional separator bar) from top to bottom of the LED matrix⁵. This allows multiple programs to display content on different regions of the matrix simultaneously.

Technical Specifications

Specification	Details
Language	Arduino/C++1
Target	Framework Laptop 16 LED Matrix Input Module (RP2040)1
LED controller	IS31FL3741A3
Grid size	9×34 (306 LEDs)1
Brightness	256 levels (full range)1
Refresh rate	~80 FPS1
Interface	USB serial1
License	MIT1
Commits	201
GitHub Stars	41
Source	sigroot/FW_LED_Matrix_Firmware (GitHub)1

Related Projects

Project	Description
sparkle-fw16	C-based alternative firmware using the Glitter Protocol (USB HID)
LED Matrix Controllers	Cross-firmware JS/TS library supporting sigroot firmware
LED Matrix Vocab	Japanese vocabulary tool with sigroot firmware auto-detection
led-matrix-manager	Qt GUI for LED matrix management
fw16-led-matrixd	Cross-platform Rust daemon for the LED matrix

Footnotes

1. sigroot/FW_LED_Matrix_Firmware — GitHub (README, capabilities, installation instructions) ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰ ↩²¹ ↩²² ↩²³ ↩²⁴ ↩²⁵ ↩²⁶ ↩²⁷ ↩²⁸ ↩²⁹ ↩³⁰ ↩³¹ ↩³² ↩³³

2. FrameworkComputer/InputModules — GitHub (official InputModules documentation, lists third-party firmware) ↩ ↩²

3. sigroot/FW_LED_Matrix_Firmware — rp2040_firmware.h — GitHub (source code: IS31FL3741A registers, gamma correction, pixel mapping) ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

4. sigroot/FW_LED_Matrix_Interface — GitHub (Rust interface library) ↩

5. sigroot/FW_LED_Matrix_Board — GitHub (applet server, 9×11 grid division) ↩ ↩²