tmk/tmk_keyboard
Tmk Keyboard
tmk_keyboard is keyboard firmware for AVR and Cortex-M microcontrollers designed to handle key matrix scanning and HID communication. It functions as an embedded hardware control library for managing GPIO pins and EEPROM storage, as well as a driver that transmits keystroke and mouse data to a host computer via USB or PS/2 protocols.
The project features a layer-based keymap engine that allows physical keys to be mapped to multiple virtual layers. It also includes a legacy keyboard protocol translator to convert signals from vintage hardware standards to modern computer interfaces.
The firmware supports a range of input configurations, including key macros, mouse input emulation, and advanced key modifiers. It provides capabilities for system control, such as media playback and power management, and includes tools for managing LED backlighting and debugging firmware communication.
Features
- Keyboard Firmware - Provides low-level firmware for managing key matrix scanning, debouncing, and keymap processing on microcontrollers.
- Layered Keymaps - Implements a layer-based keymap engine allowing physical keys to serve multiple virtual functions.
- Keyboard Key Mappings - Defines multiple keyboard layouts that can be toggled using dedicated trigger keys.
- Advanced Mapping Engines - Implements a logic engine that coordinates complex input behaviors like macros and tap-hold functions.
- Keyboard Matrix Scanning - Implements the polling of rows and columns in a physical switch matrix to detect key presses.
- Layer-Based Keymap Resolution - Implements logic to resolve physical key inputs to keycodes using a stack of functional layers.
- HID Device Implementations - Implements low-level USB and PS/2 HID communication to transmit keystroke data to the host.
- HID Keyboard Drivers - Implements a driver to transmit keystroke and mouse data to a host via USB or PS/2.
- Interrupt-Driven Signal Handlers - Uses hardware-timed interrupt routines to manage real-time HID communication for keystroke transmission.
- Keyboard Layout Layers - Provides dynamic mapping layers that change key functions based on the active virtual layer.
- Microcontroller Programming - Provides the means to write and deploy firmware to AVR and Cortex-M microcontrollers for keyboard control.
- Register-Level Controllers - Implements direct register manipulation for microcontroller I/O pins to ensure low-latency keyboard input processing.
- Embedded Device Hardware Control - Provides low-level management of embedded hardware peripherals including GPIO pins, EEPROM, and LED backlighting.
- Custom Key Behavior Definitions - Allows the creation of specialized key behaviors and functions through custom firmware-level event interception.
- Hardware Signal Emulation - Translates legacy keyboard signals into formats compatible with modern computer interfaces.
- HID Mouse Emulation - Emulates HID mouse report protocols to send cursor movement and click commands via keyboard keys.
- Input Sequence Macros - Records and plays back pre-defined sequences of keystrokes triggered by a single key.
- Protocol Translation - Translates signals from vintage keyboard hardware standards to modern computer interfaces.
- Legacy Protocol Translators - Converts signals from vintage hardware keyboard standards to modern computer interfaces.
- One-Shot Modifiers - Implements advanced input behaviors such as one-shot modifiers and tapping-based activation.
- N-Key Rollover Support - Reports many keys and modifiers simultaneously to prevent ghosting during rapid typing.
- Non-Volatile Setting Persistence - Provides non-volatile storage in EEPROM to preserve user keymaps and hardware settings across power cycles.
- Hardware Input Translation - Converts signals between different hardware standards to ensure compatibility between mismatched keyboard components.
- Modifier State Tracking - Maintains a boolean registry of active modifier keys to determine final output characters.
