DESCRIPTION

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. It interfaces directly with microprocessors and may be used in a polled or interrupt driven system. It is manufactured in a CMOS process.

FEATURES

• Dual full-duplex asynchronous receiver/transmitter

• 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

• Programmable baud rate for each receiver and transmitter selectable from:

– 22 fixed rates: 50 to 115.2 k baud

• 16-bit programmable Counter/Timer

– Non-standard rates to 115.2 kb

– One user-defined rate derived from programmable timer/counter

– 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 resistor

• Multi-function 8-bit output port

– Individual bit set/reset capability

– Outputs can be programmed to be status/interrupt signals

– 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: 1× – 1 MB/sec; 16× – 125 kB/sec

• 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