Glossary

UF2

USB Flashing Format used for drag-and-drop firmware updates on supported boards.

REPL

Read-Eval-Print Loop. An interactive prompt where you can run JavaScript commands.

USB

Universal Serial Bus. Used here for power, serial access, and the on-device drive.

CDC

Communications Device Class. USB profile for serial console access.

MSC

Mass Storage Class. USB profile that shows the board as a drive.

GPIO

General-Purpose Input/Output. The digital pins you read from or write to.

PWM

Pulse-Width Modulation. Used for LED dimming, motors, or signal generation.

I2C

Inter-Integrated Circuit. Two-wire bus for sensors and peripherals.

SPI

Serial Peripheral Interface. Fast serial bus for displays, sensors, and storage.

ADC

Analog-to-Digital Converter. Reads analog voltages.

NeoPixel

Brand name for WS2812 addressable RGB LEDs, often using GRB color order.

RP2040

Dual-core microcontroller used in Raspberry Pi Pico.

RP2350

Microcontroller used in Raspberry Pi Pico 2.

BOOTSEL

A hardware button on Pico boards that starts the UF2 bootloader when held during power-on.

Bootloader

Small firmware that runs before your app and accepts new UF2 files.

Firmware

The compiled runtime that runs on the board.

CommonJS

The require() module system used by Node.js and mcujs.

JerryScript

The lightweight JavaScript engine used by mcujs.

Pico SDK

The Raspberry Pi Pico C/C++ SDK used to build the firmware.

Runtime

The core JavaScript environment running on the board.

Mascot

A friendly character that represents the project and shows up in docs or UI.