Pin Configurations - Philips SCC2691 Product Data Sheet

Universal asynchronous receiver/transmitter

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Philips Semiconductors

Universal asynchronous receiver/transmitter (UART)

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

2006 Aug 04