SCC2691

General description

The Philips Semiconductors SCC2691 Universal Asynchronous Receiver/Transmitter (UART) is a single-chip CMOS-LSI communications device that provides a full-duplex asynchronous receiver/transmitter. It is fabricated with Philips Semiconductors CMOS technology which combines the benefits of high density and low power consumption.

The operating speed of the receiver and transmitter can be selected independently as one of 18 fixed baud rates, a 16X clock derived from a programmable counter/timer, or an external 1X or 16X 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 UART particularly attractive for dual-speed channel applications such as clustered terminal systems.

The receiver is quadruple buffered to minimize the potential of receiver overrun or to reduce interrupt overhead in interrupt driven systems. In addition, a handshaking capability is provided to disable a remote UART transmitter when the receiver buffer is full.

The UART provides a power-down mode in which the oscillator is frozen but the register contents are stored. This results in reduced power consumption on the order of several magnitudes.

The UART is fully TTL compatible and operates from a single +5V power supply.

Features

• Full-duplex asynchronous receiver/transmitter
• Quadruple buffered receiver data register
• 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
• Baud rate for the receiver and transmitter selectable from:
  • 22 fixed rates: 50 to 115.2K baud
  • Non-standard rates to 115.2 kb
  • Non-standard user-defined rate derived from programmable timer/ counter
  • External 1X or 16X clock
• Parity, framing, and overrun 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
• Single interrupt output with seven maskable interrupting conditions
• On-chip crystal oscillator
• Low power mode
• TTL compatible
• Single +5V power supply
• Commercial (0 Cel to +70 Cel) and industrial (-40 Cel to +85 Cel) temperature versions available
• SOL, PLCC and 300 mil wide DIP packages available

Products/packages

The variants in the table below are discontinued. See the table Discontinued information for more information.

Quality/reliability/chemical content

The variants in the table below are discontinued. See the table Discontinued information for more information.

Quality and reliability disclaimer

Pricing/ordering/availability

Discontinued information

Applications

Related applications
LCD TV - MMS functionality
Set-top box - MMS functionality

Block diagrams/pinning

Design support

Application Notes

AN10353; Application of UART in GPS navigation system (2005-03-01)

AN10251; Automatic '485' turn-around (2003-10-27)

AN405; SCN2681/SCN68681 And SCC2691 Data Communications (1998-09-21)

AN10307; UART to Bluetooth interfacing (2004-08-11)

AN413; Using The Datacomm Product's On-Chip Oscillator (1988-10-02)

Support Documents

web; IBIS and HSPICE Model ()

Parametrics/similar products

Similar products
SCC2691 links to the similar products page containing an overview of products that are similar in function or related to the type number(s) as listed on this page. The similar products page includes products from the same catalog tree(s), relevant selection guides and products from the same functional category.

Print / Email

• Print this information
• Email this information

Disclaimers

• General product disclaimer
• Quality and reliability disclaimer