Adafruit Feather STM32F405 Express

Jargon buster

Plain-language definitions for the technical terms used above.

Bootloader

Small starter software on a microcontroller that lets new code be uploaded before the main program runs. Knowing how to enter bootloader mode matters when you need to program the board or recover it after a faulty sketch.

CircuitPython

A beginner-friendly version of Python designed to run directly on microcontroller boards. If a product supports CircuitPython, you can often program it by copying code files onto the board rather than setting up a more complex toolchain.

DFU

Device Firmware Update is a mode that lets you load new firmware onto a board over USB. It matters when recovering a board or installing firmware without using a separate programmer.

FPU

A floating-point unit is hardware inside a processor that speeds up calculations with decimal numbers. This helps when projects use maths-heavy tasks such as motion sensing, filtering sensor readings, or audio processing.

GPIO

General-purpose input/output pins are microcontroller pins you can set in software to read signals, switch devices on and off, or connect to peripherals. The number of GPIO pins matters because it limits how many buttons, LEDs, sensors, and other parts you can wire directly to the board.

I2C

I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.

LiPo

A lithium polymer rechargeable battery commonly used in portable electronics projects. It matters because LiPo batteries need correct charging circuitry and care, and this board includes hardware intended for that battery type.

MicroPython

A version of the Python programming language made to run on microcontrollers. It matters because it lets beginners write readable code to control LEDs, sensors, motors and displays without needing to start with lower-level languages.

microSD card

A microSD card is a small removable memory card used to store files such as audio tracks. For this product, the card is where the sound files live, so its capacity and formatting can affect how many sounds you can use.

NeoPixel

A type of addressable LED system where colour data is sent along a single digital data line from one LED or controller to the next. Compatibility matters because the timing and signal format must match for the lights or driver board to respond correctly.

PWM

Pulse Width Modulation is a way for a digital pin to simulate variable output power by switching on and off very quickly. It matters for controlling things like LED brightness, motor speed, or servo-style signals from a microcontroller pin.

Qwiic

Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.

RGB

Short for red, green and blue, usually referring to an LED that can mix those three colours. It matters because controlling an RGB LED teaches how separate outputs combine to create different colours.

SPI

A fast serial communication bus often used for displays, memory cards, and sensors. It matters because SPI devices need specific pins for clock and data, plus a separate chip-select line for each device.

SRAM

Fast temporary memory used by a processor while a program is running. More SRAM helps with projects that handle larger data buffers, networking, displays, or more complex code.

STEMMA

A plug-and-cable connection system used on some maker electronics boards to make wiring simpler. If a product uses STEMMA, you need the matching cable or connector type to plug it in without soldering.

STEMMA QT

A small plug-in connector system for I2C boards that lets you connect compatible sensors and controllers without soldering. It matters because it can make wiring faster and less error-prone, especially when adding several small modules to a project.

STM32

STM32 is a family of microcontroller chips commonly used in embedded electronics. Knowing a product uses an STM32 can help when looking at firmware updates, pin connections, or low-level serial control options.

UART

UART is a simple serial connection that sends data over separate transmit and receive wires, often labelled TX and RX. It matters because this module is designed to replace a wired UART cable with a wireless link while keeping the same serial data format.