Adafruit Bluefruit LE UART Friend - Bluetooth Low Energy (BLE)

Jargon buster

Plain-language definitions for the technical terms used above.

AT command set

An AT command set is a text-based control language sent over a serial terminal to configure a device. It matters because you can change settings such as baud rate and flow control without writing custom firmware.

BLE

BLE stands for Bluetooth Low Energy, a Bluetooth mode designed for low power use and broad compatibility with modern phones and computers. It connects well to battery-powered and mobile devices, including Apple hardware, though it behaves differently from Bluetooth Classic and its serial-style profiles.

CTS

CTS stands for Clear To Send, a serial flow-control signal that tells the other device it may transmit. It matters for reliable high-speed serial communication where buffers could otherwise overflow.

HID

Human Interface Device is a USB device class used for keyboards, mice, gamepads and similar controls. If a board supports HID over USB, it can act like an input device to a computer without needing a custom driver.

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.

OTA

OTA means over-the-air updating, where a device's firmware is updated wirelessly rather than through a programming cable. This lets firmware be updated or maintained after a device is installed without a physical connection.

RTS

RTS stands for Request To Send, a serial flow-control signal used to manage when a device is ready to receive data. It matters when moving fast serial streams because flow control can help prevent lost data.

RX

RX means receive, usually showing data being received by the board. An RX indicator LED can help with troubleshooting USB or serial communication.

Shield

An add-on board that plugs into a main controller board to give it extra features such as sensing, motor control or communication. Knowing a product supports shields helps you judge whether it can connect neatly into an existing maker-board setup.

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.

TX

TX means transmit, usually showing data being sent from the board. A TX indicator LED can help you see when the board is communicating or uploading code.

TX/RX pins

TX and RX are the transmit and receive pins used for serial communication between electronic devices. They matter when wiring the board to another controller because TX usually connects to the other device’s RX, and the voltage level must be compatible.

UART

UART is a simple asynchronous serial interface that sends data over separate transmit and receive wires, usually labelled TX and RX, with both ends set to the same baud rate. It is a common way for microcontrollers and other serial devices to exchange data.