Communication is key in electronics, and USART (Universal Synchronous and Asynchronous Receiver-Transmitter) is a critical protocol that enables devices to exchange data efficiently. It’s widely used in embedded systems, microcontrollers, and serial communication applications. In this blog, we’ll explore what USART is, how it works, and its applications.
What is USART?
USART stands for Universal Synchronous and Asynchronous Receiver-Transmitter, a hardware communication protocol used to send and receive serial data.
It can operate in two modes:

Synchronous Mode: Data transfer is synchronized with a clock signal.
Asynchronous Mode [UART]: Data transfer does not require a clock signal, relying instead on specific timing.
USART is versatile, supporting both modes and enabling seamless communication between devices.
How Does USART Work?
USART converts parallel data from a device (like a microcontroller) into a serial stream for transmission and vice versa for reception. It works through two main processes.
1. Transmission

Converts parallel data from the device into serial format.
Adds start, stop, and optional parity bits to frame the data.
Sends data bit by bit over a communication line.
2. Reception

Receives serial data bit by bit.
Strips off the start, stop, and parity bits.
Converts the data back into parallel format for the device.
Key Features of USART
1. Baud Rate Control
Specifies the speed of data transmission in bits per second (bps).
2. Data Framing
Data is sent with a start bit, data bits, an optional parity bit, and one or more stop bits.
3. Full-Duplex Communication
Simultaneous transmission and reception of data are possible.
4. Error Detection
Parity checking ensures data integrity during transmission.
Synchronous vs. Asynchronous Mode
Feature | Synchronous Mode | Asynchronous Mode |
Clock Signal | Requires a clock signal |