What is uart
Last updated: April 1, 2026
Key Facts
- UART is one of the oldest and most widely used serial communication protocols in electronics
- The protocol sends data asynchronously without a separate clock signal, using start and stop bits for synchronization
- Common UART baud rates include 9600, 19200, 38400, 57600, and 115200 bits per second
- UART connections typically use two wires for data transmission (TX and RX) plus ground
- UART is found in microcontrollers, computers, IoT devices, and many embedded systems
Overview of UART Technology
UART stands for Universal Asynchronous Receiver-Transmitter and represents a fundamental communication interface in electronics and computing. This hardware module handles the conversion between parallel data used internally by processors and serial data transmitted bit-by-bit across wires. Despite being developed in the 1960s, UART remains ubiquitous in modern devices, from Arduino microcontrollers to industrial equipment, demonstrating its reliability and practicality in diverse applications.
How UART Works
UART operates on asynchronous serial communication, meaning data transmission and reception occur without a shared clock signal. Instead, both sender and receiver operate at predetermined baud rates in bits per second that must match for proper communication. Data frames consist of a start bit, typically 5-8 data bits, an optional parity bit for error checking, and one or more stop bits. This frame structure allows the receiving device to synchronize and properly interpret the incoming data stream without requiring external clock synchronization.
Advantages and Limitations
The primary advantages of UART include simplicity, low cost, and widespread compatibility across devices and platforms. The protocol requires minimal wiring—just two data wires (transmit and receive) plus ground—making it ideal for resource-constrained applications. However, UART operates at relatively low speeds compared to modern protocols like SPI or I2C. The asynchronous nature also makes it susceptible to timing errors if baud rates are not precisely matched. Additionally, longer cables can introduce signal degradation and communication errors.
Modern Applications
Today, UART appears in numerous applications including Arduino and Raspberry Pi development boards, GPS modules, GSM cellular modules, and debugging interfaces for firmware development. Many microcontroller development boards include UART interfaces for serial communication with computers, enabling developers to upload code and monitor device behavior in real-time. In industrial settings, UART continues to be used for legacy equipment communication and specialized applications requiring simple, reliable serial data transfer across distances.
Related Questions
What is the difference between UART and USART?
USART (Universal Synchronous Asynchronous Receiver-Transmitter) supports both asynchronous and synchronous communication modes, while UART only supports asynchronous communication. USART provides more flexibility but adds complexity to implementation.
How do you connect a UART device to a computer?
UART devices connect to computers using USB-to-UART adapter cables, which convert UART serial signals to USB protocol. The adapter connects to the device's TX and RX pins while sharing ground connections.
What baud rate should I use for UART?
Common baud rates include 9600 (default for many devices), 115200 (faster communication), and 38400 (compromise option). Both sender and receiver must use identical baud rates for proper communication.
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Sources
- Wikipedia - UARTCC-BY-SA-4.0
- Electronics Tutorials - UARTFair Use