scn68681 NXP Semiconductors, scn68681 Datasheet - Page 2

• Manufacturer Part Number: scn68681
• Description: Dual Asynchronous Receiver/transmitter Duart
• Manufacturer: NXP Semiconductors

also interface easily with other microprocessors. The DUART can be
systems. In addition, a flow control capability is provided to disable a
Philips Semiconductors
DESCRIPTION
The Philips Semiconductors SCN68681 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 is compatible with other S68000 family devices, and can
used in polled or interrupt driven systems.
The operating mode and data format of each channel can be
programmed independently. Additionally, each receiver and
transmitter can select its operating speed as one of eighteen 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 DUART particularly
attractive for dual-speed channel applications such as clustered
terminal systems.
Each receiver is quadruply buffered to minimize the potential of
receiver overrun or to reduce interrupt overhead in interrupt driven
remote DUART transmitter when the buffer of the receiving device is
full.
Also provided on the SCN68681 are a multipurpose 6-bit input port
and a multipurpose 8-bit output port. These can be used as general
purpose I/O ports or can be assigned specific functions (such as
clock inputs or status/interrupt outputs) under program control.
FEATURES
ORDERING INFORMATION
2004 Mar 02
40-Pin Plastic Dual In-Line Package (DIP)
44-Pin Plastic Leaded Chip Carrier (PLCC)
S68000 bus compatible
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
– Non-standard rates to 115.2 kb
– Non-standard user-defined rate derived from programmable
– External 1X or 16X clock
Dual asynchronous receiver/transmitter (DUART)
counter/timer
DESCRIPTION
T
amb
V
SCN68681C1N40
SCN68681C1A44
2
COMMERCIAL
CC
= 0 C to +70 C
= +5 V + 5 %,
16-bit programmable Counter/Timer
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 6-bit input port
– Can serve as clock or control inputs
– Change-of-state detection on four inputs
– 100 k typical pull-up resistors
Multi-function 8-bit output port
– Individual bit set/reset capability
– Outputs can be programmed to be status/interrupt signals
Versatile interrupt system
– Single interrupt output with eight maskable interrupting
– Interrupt vector output on interrupt acknowledge
– Output port can be configured to provide a total of up to six
Maximum data transfer rates:
1X - 1 MB/sec, 16X - 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
conditions
separate wire-ORable interrupt outputs
T
amb
V
SCN68681E1N40
SCN68681E1A44
CC
INDUSTRIAL
= –40 C to +85 C
= +5 V + 10 %,
SCN68681
SOT129-1
SOT187-2
Product data
DWG #