XR88C681
CMOS Dual Channel
UART (DUART)
June 2006
FEATURES
D Two Full Duplex, Independent Channels
D Asynchronous Receiver and Transmitter
D Quadruple-Buffered Receivers and Dual Buffered
Transmitters
D Programmable Stop Bits in 1/16 Bit Increments
D Internal Bit Rate Generators with More than 23 Bit
Rates
D Programmable Interrupt Daisy Chain
D 8 General Purpose Outputs (40 Pin DIP and 44 Pin
PLCC Packages Only)
D 7 General Purpose Inputs with Change of States
Detectors on Inputs (40 Pin DIP and 44 Pin PLCC
Packages Only)
D Multi-Drop Mode Compatible with 8051 Nine Bit
Mode
D Independent Bit Rate Selection for Each Transmitter
and Receiver
D On-Chip Oscillator for Crystal
D Standby Mode to Reduce Operating Power
D Compatible with the Motorola MC2681 and
Signetics SCC2692 devices
D External Clock Capability
D Maximum Bit Rate: 1X Clock - 1Mb/s, 16X Clock -
125kb/s
D Advanced CMOS Low Power Technology
D Normal, AUTOECHO, Local LOOPBACK and
Remote LOOPBACK Modes
D Multi-function 16 Bit Counter/Timer
D Interrupt Output with Eight Maskable Interrupt
Conditions
APPLICATIONS
D Multimedia Systems
D Serial to Parallel/Parallel to Serial Converter
D DTE for Modem Communication Systems
D Interrupt Vector Output on Acknowledge (40 Pin DIP
and 44 Pin PLCC Packages Only)
GENERAL DESCRIPTION
The EXAR Dual Universal Asynchronous Receiver and
Transmitter (DUART) is a data communications 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.
The DUART is fabricatedusing advancedtwo layer metal,
with a high performance density EPI/CMOS 1.8 process
to provide high performance and low power consumption,
and is packaged in a 40 pin PDIP, a 28 pin PDIP, and a 44
pin PLCC.
The XR88C681 device offers a single IC solution for the
8080/85, 8086/88, Z80, Z8000, 68xx and 65xx
microprocessor families.
ORDERING INFORMATION
Operating
Part No.
Pin Package
44 PLCC
Temperature Range
XR88C681CJ
XR88C681CN/40
XR88C681CP/28
XR88C681CP/40
XR88C681J
0°C to 70°C
0°C to 70°C
40 CDIP
28 PDIP
40 PDIP
44 PLCC
40 CDIP
28 PDIP
40 PDIP
0°C to 70°C
0°C to 70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
XR88C681N/40
XR88C681P/28
XR88C681P/40
Rev. 2.11
E2006