Dual Asynchronous Receiver/Transmitter (DUART)

  • Archived
  • This page contains information on a product that is no longer manufactured (discontinued). Specifications and information herein are available for historical reference only.

Product Details

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Block Diagram

SCC68681C1A44, SCC68681C1N40, SCC68681E1A44, SCC68681E1N40


Key Features

  • S68000 bus compatible
  • Dual full-duplex asynchronous receiver/transmitter
  • Quadruple buffered receiver data registers
  • 16-bit programmable Counter/Timer
  • Parity, framing and overrun error detection
  • False start bit detection
  • Line break detection and generation
  • Multifunction programmable 16-bit counter/timer
  • Maximum data transfer rates: 1× = 1 MB/s; 16× = 125 kB/s
  • Automatic wake-up mode for multidrop applications
  • Start-end break interrupt/status
  • Detects break, which originates in the middle of a character
  • On-chip crystal oscillator
  • Single +5 V power supply
  • Commercial and industrial temperature ranges available
  • DIP and PLCC packages

Programmable Data Format

  • 5 to 8 data bits plus parity
  • Odd, even, no parity or force parity
  • 1, 1.5 or 2 stop bits programmable in 1/16-bit increments

Baud Rate for The Receiver and Transmitter Selectable

  • 22 fixed rates: 50 to 115.2 kBd
  • Non-standard rates to 115.2 kB
  • Non-standard user-defined rate derived from programmable counter/timer
  • External 1x or 16x clock

Programmable Channel Mode

  • Normal (full-duplex)
  • Automatic echo
  • Local loopback
  • Remote loopback

Multi-function 6-Bit Input Port

  • Can serve as clock or control inputs
  • Change-of-state detection on four inputs
  • 100 kΩ typical pull-up resistors

Multi-function 8-Bit Output Port

  • Individual bit set/reset capability
  • Outputs can be programmed to be status/interrupt/DMA signals
  • Auto 485 turn-around

Versatile Interrupt System

  • Single interrupt output with eight maskable interrupting conditions
  • Interrupt vector output on interrupt acknowledge
  • Output port can be configured to provide a total of up to six separate wire-ORable interrupt outputs


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