SCC2681TC1A44

Dual asynchronous receiver/transmitter (DUART)


The Philips Semiconductors SCC2681 Dual Universal Asynchronous Receiver/Transmitter (DUART) is a single-chip MOS-LSI communications device that provides two independent full-duplex asynchronous receiver/transmitter channels in a single package. The SCC2681T features a faster bus cycle time than the standard SCC2681. The quick bus cycle eliminates or reduces the need for wait states with fast CPUs and permits high throughput in I/O intensive systems. Higher external clock rates may be used with the transmitter, receiver and counter timer which in turn provide greater versatility in baud rate generation. The SCC2681T interfaces directly with microprocessors and may be used in a polled or interrupt driven system. It is manufactured in CMOS technology.

The operating mode and data format of each channel can be programmed independently. Additionally, each receiver and transmitter can select its operating speed as one of eighteen fixed baud rates, a 16× clock derived from a programmable counter/timer, or an external 1× or 16× clock. The baud rate generator and counter/timer can operate directly from a crystal or from external clock inputs. The ability to independently program the operating speed of the receiver and transmitter make the DUART particularly attractive for dual-speed channel applications such as clustered terminal systems.

Each receiver is quadruple buffered to minimize the potential of receiver over-run or to reduce interrupt overhead in interrupt driven systems. In addition, a flow control capability is provided to disable a remote DUART transmitter when the receiver buffer is full.

Also provided on the SCC2681T are a multipurpose 7-bit input port and a multipurpose 8-bit output port. These can be used as general purpose I/O ports or can be assigned specific functions (such as clock inputs or status/interrupt outputs) under program control.

For a complete functional description and programming information for the SCC2681T, refer to the SCC2681 product specification.

Features and benefits

  • Fast bus cycle times reduce or eliminate CPU wait states
  • Dual full-duplex asynchronous receiver/transmitters
  • Quadruple buffered receiver data registers
  • 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
  • 16-bit programmable Counter/Timer
  • Programmable baud rate for each receiver and transmitter selectable from:
    • 22 fixed rates: 50 to 115.2 k baud
    • Non-standard rates to 115.2
    • Non-standard user-defined rate derived from programmable counter/timer
    • External 1× or 16× clock
  • Parity, framing, and overrun error detection
  • False start bit detection
  • Line break detection and generation
  • Programmable channel mode
    • Normal (full-duplex)
    • Automatic echo
    • Local loopback
    • Remote loopback
  • Multi-function programmable 16-bit counter/timer
  • Multi-function 7-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
    • Output port can be configured to provide a total of up to six separate wire-ORable interrupt outputs
  • Maximum data transfer rates:
    • 1× ? 1 MB/sec transmitter and receiver
    • 16× ? 500 kB/sec receiver and 250 kB/sec transmitter
  • 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 temperature range
All information on this product information page is subject to the subsequent disclaimers:

Devices listed on this page should not be used for new designs!

This product has been discontinued.
Click here for discontinuation information.

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Show functional diagram

Block diagram: SCC2681TC1A44
Block diagram: SCC2681TC1A44

Parametrics of this product

Type numberPackageNumber of pinsReceiver/Transmitter typeApplicationFunctionOperating Temperature(Cel)
SCC2681TC1A44SOT187-2
(PLCC44)		44Dual UARTsData CommunicationReceivers/Transmitters0~70

Similar products

Package

All type numbers in the table below are discontinued. See the table Discontinuation information at the bottom of this page for more information.

Type numberOrderable part numberOrdering code (12NC)Product statusPackagePackingMarking
SCC2681TC1A44SCC2681TC1A44,5129352 745 19512Discontinued
Replacement product		SOT187-2
(PLCC44) 		Tube Dry PackSCC2681TC1A44
SCC2681TC1A44SCC2681TC1A44,5299352 745 19529Discontinued
Replacement product		SOT187-2
(PLCC44) 		SCC2681TC1A44
SCC2681TC1A44SCC2681TC1A44,5189352 745 19518Discontinued
Replacement product		SOT187-2
(PLCC44) 		Reel Dry Pack, SMD, 13"SCC2681TC1A44

Outline drawing

Package VersionPackage NamePackage DescriptionReference CodesIssue Date
SOT187-2PLCC44plastic leaded chip carrier; 44 leadsEDR-7319 (EIAJ); MS-018 (JEDEC); 112E10 (IEC); 2001-11-14

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Wave soldering

Discontinuation information

Type numberOrdering code (12NC)Last-time buy dateLast-time delivery dateReplacement productDN NoticeStatusComments
SCC2681TC1A4493527451951231-Dec-1230-Jun-13SCC2692AC1A44DN NXP-DN_201206034DNFull WithdrawalStandard End of Life. Multiple Source.
SCC2681TC1A4493527451952931-Dec-1230-Jun-13SCC2692AC1A44DN NXP-DN_201206034DNFull WithdrawalStandard End of Life. Multiple Source.
SCC2681TC1A4493527451951831-Dec-1230-Jun-13SCC2692AC1A44DN NXP-DN_201206034DNFull WithdrawalStandard End of Life. Multiple Source.

Quality, reliability & chemical content

All type numbers in the table below are discontinued. See the table Discontinuation information at the bottom of this page for more information.

Type numberOrderable part numberChemical contentRoHSLeadfree conversion dateRHFIFR (FIT)MTBF (hours)MSLMSL LF
SCC2681TC1A44SCC2681TC1A44,512SCC2681TC1A44week 9, 20053.03.333333333333333E833
SCC2681TC1A44SCC2681TC1A44,529SCC2681TC1A44week 9, 20053.03.333333333333333E833
SCC2681TC1A44SCC2681TC1A44,518SCC2681TC1A44week 9, 20053.03.333333333333333E833
Quality and reliability disclaimer

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Discontinuation information

Type numberOrdering code (12NC)Last-time buy dateLast-time delivery dateReplacement productDN NoticeStatusComments
SCC2681TC1A4493527451951231-Dec-1230-Jun-13SCC2692AC1A44DN NXP-DN_201206034DNFull WithdrawalStandard End of Life. Multiple Source.
SCC2681TC1A4493527451952931-Dec-1230-Jun-13SCC2692AC1A44DN NXP-DN_201206034DNFull WithdrawalStandard End of Life. Multiple Source.
SCC2681TC1A4493527451951831-Dec-1230-Jun-13SCC2692AC1A44DN NXP-DN_201206034DNFull WithdrawalStandard End of Life. Multiple Source.

Documentation for this product

File nameTitleTypeFormatDate
SCC2681TDual asynchronous receiver/transmitter (DUART)Data sheetpdf2004-04-06
AN10307UART to Bluetooth interfacingApplication notepdf2004-08-11
AN10353Application of UART in GPS navigation systemApplication notepdf2005-03-01
AN10320Addressing migrations of SCN devices to more advanced technologiesApplication notepdf2004-06-29
75017168High-speed UARTs and Bridge ICsBrochurepdf2012-05-14

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