Definition

USART (Universal Synchronous/Asynchronous Receiver/Transmitter)

Part of the Microprocessors glossary:

A USART (Universal Synchronous/Asynchronous Receiver/Transmitter) is a microchip that facilitates communication through a computer's serial port using the RS-232C protocol.

Like a UART (Universal Asynchronous Receiver/Transmitter), a USART provides the computer with the interface necessary for communication with modems and other serial devices. However, unlike a UART, a USART offers the option of synchronous mode. In program-to-program communication, the synchronous mode requires that each end of an exchange respond in turn without initiating a new communication. Asynchronous operation means that a process operates independently of other processes.

Practical differences between synchronous mode (which is possible only with a USART) and asynchronous mode (which is possible with either a UART or a USART) can be outlined as follows:

  • Synchronous mode requires both data and a clock. Asynchronous mode requires only data.
  • In synchronous mode, the data is transmitted at a fixed rate. In asynchronous mode, the data does not have to be transmitted at a fixed rate.
  • Synchronous data is normally transmitted in the form of blocks, while asynchronous data is normally transmitted one byte at a time.
  • Synchronous mode allows for a higher DTR (data transfer rate) than asynchronous mode does, if all other factors are held constant.

 

This was last updated in July 2012
Contributor(s): Stan Gibilisco
Posted by: Margaret Rouse

Related Terms

Definitions

  • segmented memory

    - Segmented memory is a system of addressing computer memory, which may be physical or virtual and may be operating in real or protected mode. The segmented memory system was used to expand the 64KB... (WhatIs.com)

  • Intel 8086

    - The Intel 8086 was Intel’s first x86 processor. Released in 1978, the 8086 began the long line of Intel’s most successful architecture, which eventually included the 80286, 80386 and 80486. (WhatIs.com)

  • Intel 80486

    - Intel 80486, also known as i486 or just 486, is the fourth-generation generation Intel x86 microprocessor. The 80486 was capable of over 40 million instructions per second (MIPS) and offered rough... (WhatIs.com)

Glossaries

  • Microprocessors

    - Terms related to microprocessors, including definitions about silicon chips and words and phrases about computer processors.

  • Internet applications

    - This WhatIs.com glossary contains terms related to Internet applications, including definitions about Software as a Service (SaaS) delivery models and words and phrases about web sites, e-commerce ...

Ask a Question About USART (Universal Synchronous/Asynchronous Receiver/Transmitter)Powered by ITKnowledgeExchange.com

Get answers from your peers on your most technical challenges

Tech TalkComment

Share
Comments

    Results

    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.