Adafruit CH9328 UART to HID Keyboard Breakout

Jargon buster

Plain-language definitions for the technical terms used above.

baud

Baud is the signalling rate of a serial connection, often used as the speed setting for UART communication. Matching the baud rate matters because both connected devices must use the same setting for readable data.

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.

DIP switch

A DIP switch is a small set of physical on/off switches used to configure hardware settings without software. It matters because changing features such as auto power-on or charging limits may require moving these tiny switches correctly.

ESP32

ESP32 is a family of low-cost microcontroller chips and modules from Espressif with built-in WiFi and Bluetooth. They support programmable firmware and over-the-air updates, and are commonly programmed with toolchains such as the Arduino core and ESP-IDF.

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.

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.

native USB

Native USB means the microcontroller itself handles USB communication, rather than using a separate USB-to-serial chip. This matters for programming, debugging, and projects that need the board to act directly as a USB device.

single-board computer

A complete computer built onto one circuit board, usually including the processor, memory, ports, and connectors. This matters because accessories like heatsinks must match the board’s layout and mounting holes to fit properly.

Type-C

USB Type-C (USB-C) is a small, reversible USB connector used for charging, power, and data transfer on many modern devices. A Type-C port or plug indicates the cable and charger connection needed to power, charge, or communicate with a device.

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.

USB host

A USB host is the side of a USB connection that controls attached devices, like a computer talking to a keyboard or flash drive. This matters because most microcontroller boards are normally USB devices, so adding USB host support lets them use common USB peripherals.

USB Type-C

USB Type-C is a small, reversible USB connector used for power, data and sometimes video on many modern devices. The connector itself does not guarantee a particular speed or voltage, so check the supported USB version, data rate and whether it carries more than 5V via USB Power Delivery.