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