Exar
Corporation 48720 Kato Road, Fremont CA, 94538
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(510) 668-7000
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FAX (510) 668-7017
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www.exar.com
XR16C864
2.97V TO 5.5V QUAD UART WITH 128-BYTE FIFO
APRIL 2013 REV. 2.2.0
GENERAL DESCRIPTION
The XR16C864
1
(864) is an enhanced quad
Universal Asynchronous Receiver and Transmitter
(UART) each with 128 bytes of transmit and receive
FIFOs, transmit and receive FIFO counters and
trigger levels, automatic hardware and software flow
control, automatic RS-485 half-duplex direction
control and data rates of up to 2 Mbps. Each UART
has a set of registers that provide the user with
operating status and control, receiver error
indications, and modem serial interface controls.
System interrupts may be tailored to meet design
requirements. An internal loopback capability allows
onboard diagnostics. The 864 is available in the 100-
pin QFP package. The XR16C864 offers faster
channel status access by providing separate outputs
for TXRDY and RXRDY, offer separate Infrared TX
outputs and a separate clock input for channel C
(CHCCLK). The XR16C864 is compatible with the
industry standard ST16C654 and XR16C854.
N
OTE
:
1 Covered by U.S. Patent #5,649,122 and #5,949,787.
FEATURES
Added feature in devices with top mark date code of
"F2 YYWW" and newer:
■
5 volt tolerant inputs
•
2.97 to 5.5 Volt Operation
•
Pin-to-pin compatible with the industry standard
ST16C654 and XR16C854
•
Intel or Motorola Data Bus Interface select
•
Four independent UART channels
■
Register Set Compatible to 16C550
■
Data rates of up to 2 Mbps
■
Transmit and Receive FIFOs of 128 bytes
■
Programmable TX and RX FIFO Trigger Levels
■
Transmit and Receive FIFO Level Counters
■
Automatic Hardware (RTS/CTS) Flow Control
■
Selectable Auto RTS Flow Control Hysteresis
■
Automatic Software (Xon/Xoff) Flow Control
■
Wireless Infrared (IrDA 1.0) Encoder/Decoder
•
Sleep Mode (200 uA typical)
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Crystal oscillator or external clock input
APPLICATIONS
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Portable Appliances
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Telecommunication Network Routers
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Ethernet Network Routers
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Cellular Data Devices
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Factory Automation and Process Controls
F
IGURE
1. XR16C864 B
LOCK
D
IAGRAM
X TA L1
X TA L2 C ry s tal O sc/B uffer
Intel o r
M o to ro la
D ata B us
In terface
U A R T C ha n ne l A
128 B yte T X F IFO
128 B yte R X FIF O
BR G
IR
EN D E C
TX & R X
U A R T
R egs
2.97V to 5.5V V C C
854 B LK
TX B , R X B , IR T X B, D T R B # ,
D S R B # , R TS B #, C T S B# ,
C D B# , R IB # , O P 2 B # ,
O P 1B # /R S -4 8 5
U A R T C ha n nel B
(sa m e a s C ha nnel A )
A2 :A 0
D 7:D 0
C S # A-D
16/68#
IN T A -D
IO W #
IO R #
R ese t
IN TS E L
C H C C LK
TX R D Y # A-D
R X R D Y # A -D
U A R T C ha n nel C
(sa m e a s C ha nnel A )
TX A , R X A , IR T X A, D T R A # ,
D S R A # , R TS A #, C T S A# ,
C D A# , R IA # , O P 2 A # ,
O P 1A # /R S -4 8 5
TX C , R X C , IR T X C , D TR C # ,
D S R C # , R T SC # , C TS C # ,
C D C #, R IC #, O P 2C # ,
O P 1C #/R S -485
U A R T C ha n nel D
(sa m e a s C ha nnel A )
TX D , R X D , IR T X D , D TR D # ,
D S R D # , R T SD # , C TS D # ,
C D D #, R ID #, O P 2D # ,
O P 1D #/R S -485
5V to le ran t inp uts (except XTA L1)
TC
AE N
D A C K A -D
TX D R Q # A -D
R X D R Q # A -D
D irect
M e m ory
Ac cess
BC L K A -D
C LK S E L
