This repository includes mechanical and electrical documentation for the Input Module system in the Framework Laptop 16. Input Modules are hot-swappable USB 2.0-interfaced devices that enable deep customization of the input system on the Framework Laptop 16. It's also possible to use these as standalone USB 2.0 devices with a simple adapter for development purposes.

Input Modules come in three sizes, each of which has the same electrical interface:

1. Keyboard-sized modules (283.16mm wide)
2. Numpad-sized modules (67.85mm wide)
3. Half-sized modules (33.825mm wide)

For reference firmware for different types of modules, check out these additional repositories:

• QMK firmware for the keyboard and numpad modules
• inputmodule-rs firmware and application for other input modules

Input Modules © 2023-2026 by Framework Computer Inc is licensed under CC BY 4.0. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

All keyboards (ANSI, ISO, Numpad, Macropad) run QMK firmware. Find the latest binary releases and source code in our FrameworkComputer/qmk_firmware repository.

To configure keybindings, use our hosted VIA fork, which has the right configurations built in at https://keyboard.frame.work. Or the qmk_hid native Python or Rust software GUI and console applications.

HALs for RTOS or baremetal environments:

• rust-embedded
  • capslock Sample
  • white_backlight Sample
• Zephyr

IS31FL3743 LED Controller Drivers:

• QMK
• rust-embedded
• CircuitPython

Official firmware that ships with the modules is available in source and binary at FrameworkComputer/inputmodule-rs. That same repository also contains a Rust commandline utility and Python scripts to control the matrix.

HALs for RTOS or baremetal environments:

• rust-embedded
  • ledtest Sample
• Zephyr

IS31FL3741 LED Controller Drivers:

• QMK
• rust-embedded
• CircuitPython

Third party applications that interact with the official firmware:

• https://github.com/jpadgett314/led-matrix-vocab - A japanese vocab trainer

Third party firmware projects that run on the official hardware:

• https://github.com/sigroot/FW_LED_Matrix_Firmware - Arduino based firmware with an alternative host protocol
• https://github.com/vddCore/sparkle-fw16 - Pico SDK based firmware with an alternative host protocol

CircuitPython can run on all modules.

Sample Code:

• github.com/FrameworkComputer/Framework_Inputmodule_CircuitPython

Libraries:

• Keyboard RGB Controller Adafruit_CircuitPython_IS31FL3741
• Keyboard RGB Controller - Framework CircuitPython_IS31FL3743

In the Mechanical folder, we have 2D drawings of the different Input Module sizes. Note that there are two version of each:

1. A version with full mechanical structure with a separate interface PCB and brackets. This is what our production modules are based on.
2. A simplified version that allows the PCB to be used as the mechanical structure of the module, making it much cheaper and easier to make. Note that to make the PCB attach securely in the system, you'll need to solder SMT nuts like Keystone 24929 or to adhere a steel plate to attract to the magnets in the system.

In the Electrical folder, we have a reference version of a minimal RP2040-based Input Module, made in KiCAD.

Viewed from top:

The LED matrix and plastic spacers are both C size.

Each Input Module supports up to 500mA on the 5V rail and 100mA on the 3.3V rail when active.

The Framework Laptop 16 has a protection scheme in place to prevent Input Modules from powering on unless the input deck is fully populated. Module detection is done using the BOARD_ID pin. It is possible to override this setting on the system through BIOS settings, but at the risk of shorting the system or modules.

System firmware expects that pogo connector where the module presents the board ID, is at the very left of the module. It uses this assumption to calculate size and position of modules and detect if the input deck is fully populated and all pogo pins are covered.

On the first generation Framework 16 with BIOS 3.XX the SLEEP# pin is low whenever the system is in S0ix (suspend) state or the lid is closed.

On the 2nd gen or 1st gen with BIOS 4.XX the SLEEP# pin is only low if the lid is closed. This change was made because the keyboard and touchpad firmware couldn't decide between

When SLEEP# is low or USB is in Selective Suspend mode, modules should drop below 500uA on each rail. This will typically occur when the system enters an S0ix state. In S3/S4/S5 or when the laptop lid is closed, the power rails will typically be off.

F2 on boot > Setup Utility > Advanced > Force Power for Input Modules:

• Force Off: Power always off
• Require Modules (default): Power on only if all modules are present
• Force On: Power always on

In the case of Force On, there is a risk of damage when the pins are exposed and come into contact with conductive material.

This section describes the Touchpad Module connection on the system side, including the pin define and the pin map of the connector. There are three connectors for the touchpad, to allow moving it around. They are all shorted together on the same I2C bus with the same interrupt lines.

Pins on the connector have ESD protection to meet IEC 61000-4-2 Level 4 protection.

The contacts on the Touchpad should be designed so that the ground pins engage first when the Touchpad is sliding in. Pin 7 should be 0.5mm longer than the other pins to ensure it engages first.

The below picture for pads is shown in perspective. The view angle is on top of the PCB.

Around the signal pads there should be a ground fill keepout to prevent the pogo connectors from shorting the pads to ground or other signals when sliding in if the solder mask is scraped away.

The I2C bus from the touchpad is connected to the CPU for HID over I2C and implements the Precision Touchpad Protocol.

It's also connected to the EC. This is used when booting without a touchpad. If the Windows driver tries to connect to an I2C device but finds it does not respond, it will disable that device. So we make the EC pretend to be the touchpad and send the same HID report descriptor as the touchpad would.

See One Key Module.