SparkFun 16 Output I/O Expander Breakout - SX1509

Jargon buster

Plain-language definitions for the technical terms used above.

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.

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.

Headers

Rows of connector contacts on a fixed pitch (commonly 2.54 mm) used to link a board to a breadboard, jumper wires, or another board. They come as male pin headers and female socket headers; when a module ships with pre-soldered headers it can be used straight away, whereas bare pads require soldering the pins yourself.

LED driver

An LED driver is a control chip or circuit that supplies and switches power to LEDs. For a display board, it reduces the number of microcontroller pins needed and handles tasks like lighting the right segments and adjusting brightness.

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.

multiplexer

A multiplexer (mux) is a chip or circuit that selects one of several input signals and routes it to a single shared output, with select lines choosing which input is connected; running the same idea in reverse, to send one input to a chosen output, gives a demultiplexer. Multiplexers let a single controller or line work with several signals or devices that would otherwise clash on a shared connection.

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.