DESCRIPTION

The Epic Ei88C681/Ei68C681 DUART Dual Universal Asynchronous Receiver and Transmitter is a data communication device that provides two fully independent full duplex asynchronous communication channels in a single package. The DUART is designed for use in microprocessor based systems and may be used in a polled or interrupt driven environment.

FEATURES

• Full duplex, dual channel asynchronous

receiver and transmitter

• Quadruple-buffered receiver and transmitter

• Stop bits programmable in 1/16-bit increments

• Internal bit rate generator with 23 bit rates

• Independent bit rate selection for each Rx

and Tx

• Maximum bit rate: 1 x clock - 2 Mb/sec., 16

x clock- 250 Kb/sec.

• Normal, auto-echo, local loop-back and

remote loop-back modes

• Multi-function 16-bit counter/timer

• Interrupt output with 8 maskable interrupting

conditions

• Interrupt vector output on acknowledge

• Programmable interrupt daisy chain

• Up to 15 I/O pins (depending on package

and version)

• Multidrop mode compatible with 8051 ninebit mode

• On-chip oscillator for crystal

• Stand-by mode to reduce operating power

• Advanced CMOS low power technology