Qwiic Directional Pad (PRT-26851)

Jargon buster

Plain-language definitions for the technical terms used above.

active LOW

Active LOW describes a signal that is treated as active, asserted or 'on' when it sits at a low voltage near ground, rather than at a high voltage. It applies to inputs, outputs and control lines (such as reset or chip-select), so it matters when wiring devices so that signal levels are interpreted as intended.

breakout

A breakout board carries a small or fine-pitched component and brings its connections out to standard, breadboard- and header-friendly pins. Describing a part as a breakout means it can be wired into a project without soldering directly to the component's tiny contacts.

GND

GND is the ground or reference connection (0 V) for a circuit. When connecting two devices together, their grounds must be joined so both agree on what counts as a low or high signal.

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.

I/O expander

An I/O expander is a chip that adds extra input and output pins controlled through a bus such as I2C or SPI. It can drive buttons, LEDs, relays, resets, or other control lines without using up scarce microcontroller pins.

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.

I2C address

An I2C address is the number a device uses so a microcontroller can tell it apart from other devices on the same I2C bus. It matters because two devices with the same fixed address may conflict if used together.

LED

A light-emitting diode (LED) is a small electronic component that emits light when current flows through it in the correct direction. Because it only conducts one way, its polarity matters, and a through-hole LED must be soldered the correct way around to light up.

microcontroller

A microcontroller is a small computer on a single chip that runs a stored program and controls connected inputs and outputs such as buttons, sensors, displays and communication interfaces. In a device built around one, it is the part that executes the code and coordinates the device's behaviour.

PCA9554

The PCA9554 is an I/O expander chip that adds extra digital input and output pins over an I2C bus. On a display driver board, it can handle support signals such as reset, buttons, or backlight control while leaving the main microcontroller pins free.

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, the three primary colours of light that are mixed in varying amounts to make a wide range of colours. In electronics RGB can refer to an LED or pixel that blends these three colours, or to a colour signal or interface that carries separate red, green and blue channels.