Open Source Keyboard Appliance powered by Rust

OSKAR is a firmware for the Raspberry Pi Pico it combines the 9elements picoprog project and additional Hid code into a firmware for our multi-feature Makro-Keypad.

Prerequisites

Before you can compile and use OSKAR, you need to install the following dependencies:

• Rust and Cargo: Follow the instructions on the official Rust website to install Rust and Cargo.
• Install flip-link and elf2uf2

# Only Linux
sudo apt install build-essential libudev-dev pkg-config

# All systems
cargo install flip-link elf2uf2-rs

Compiling the Firmware

To compile the firmware, follow these steps:

1. Clone the repository:

git clone https://github.com/9elements/OSKAR.git
cd OSKAR

Build the firmware:

cargo run --release

3. The compiled binary will be located in the target/thumbv6m-none-eabi/release directory.

Flashing the Firmware

To flash the firmware onto the Raspberry Pi Pico, follow these steps:

1. Connect the Raspberry Pi Pico to your computer while holding the BOOTSEL button. This will put the Pico into USB mass storage mode.

2. Copy the UF2 file to the Pico:

# Linux
cp target/thumbv6m-none-eabi/release/oskar.uf2 /path/to/pi/volume

# macOS
cp target/thumbv6m-none-eabi/release/picoprog.uf2 /Volumes/RPI-RP2/

3. The Pico will automatically reboot and start running the new firmware.

Usage

Modes

The Device features a 3-position selection switch on its left side. When the switch is moved all the way to the back it simply acts ats the picoprog featuring SPI and UART capabillities (Green LED). Moved all the way to the fromt it acts as Macro Keyboard (Red LED). With the switch in the middle position the device combines Both features at once (purple led).

Makro Keyboard

The standard firmware of the Keyboard hase the encoder configured as volume knob with mute on press. The keys 1-3 (from left to right) are configured as o s and f (for open source firmware).

At the top of the file src/hid.rs there is a constant struct called KEYLAYOUT.

const KEYLAYOUT:KeyLayout = KeyLayout {
    encoder_left: KeyType::Media(MediaKey::VolumeDecrement),
    encoder_right: KeyType::Media(MediaKey::VolumeIncrement),
    encoder_button: KeyType::Media(MediaKey::Mute),
    key1: KeyType::Keycode(KeyboardUsage::KeyboardOo),
    key2: KeyType::Keycode(KeyboardUsage::KeyboardSs),
    key3: KeyType::Keycode(KeyboardUsage::KeyboardFf),
};

The struct holds the current configuration of the Keyboard, each key can be configured to any keycode of the enum KeyType located in src/hid_codes.rs for example:

const KEYLAYOUT:KeyLayout = KeyLayout {
    encoder_left: KeyType::Media(MediaKey::VolumeDecrement),
    encoder_right: KeyType::Media(MediaKey::VolumeIncrement),
    encoder_button: KeyType::Media(MediaKey::Mute),
    key1: KeyType::Keycode(KeyboardUsage::KeyboardF10),
    key2: KeyType::Keycode(KeyboardUsage::KeyboardF11),
    key3: KeyType::Keycode(KeyboardUsage::KeyboardF12),
};

Wich could then be used to be configured as hotkeys in your operating system.

Serial (picocom or combined mode)

Once the firmware is running, you can use any terminal program to communicate with the UART and SPI peripherals via USB. The device will appear as a USB CDC (Communications Device Class) device. Currently /dev/ttyACM0 (macOS: /dev/tty.usbmodemOSFC20241) is a debug console that prints information about the picos current operation.

UART Communication (picocom or combined mode)

To communicate with the UART peripheral, open the corresponding serial port (e.g., /dev/ttyACM1 on Linux, /dev/tty.usbmodemOSFC20243 on macOS) with your terminal program. For now the Baud is fixed at 115200 but can be changed in code. Dynamic reconfiguration is still planned.

Using Flashrom or Flashprog (picocom or combined mode)

To interact with the Raspberry Pi Pico in for reading and writing SPI flash chips, you can use tools like flashrom or flashprog. These tools support the serprog protocol, which allows communication over a serial interface.

1. Install flashrom or flashprog e.g.:

# Debian or Debian-based Linux distributions
sudo apt-get install flashrom

# macOS with Homebrew
brew install flashrom

2. Use the following command to read from the SPI flash chip:

flashrom -p serprog:dev=/dev/ttyACM2 -r backup.bin

This command reads the contents of the SPI flash chip and saves it to backup.bin.

3. Use the following command to write to the SPI flash chip:

flashrom -p serprog:dev=/dev/ttyACM2 -w firmware.bin

This command writes the contents of firmware.bin to the SPI flash chip.

Make sure to replace /dev/ttyACM2 with the correct serial port if your device is connected to a different port or if you're on a different operating system (on macOS it will be /dev/tty.usbmodemOSFC20245).

License

This project is licensed under the Apache 2.0 License. See the LICENSE file for details.