xr
AUGUST 2005
XR16C850
2.97V TO 5.5V UART WITH 128-BYTE FIFO
REV. 2.3.1
GENERAL DESCRIPTION
The XR16C850
1
(850) is a Universal Asynchronous
Receiver and Transmitter (UART). This device
supports Intel and PC mode data bus interface and is
software compatible to industry standard 16C450,
16C550, ST16C580 and ST16C650A UARTs.
The 850 has 128 bytes of TX and RX FIFOs and is
capable of operating up to a serial data rate of 2
Mbps. The internal registers include the 16C550
register set plus Exar’s enhanced registers for
additional features to support today’s highly
demanding data communication needs. The
enhanced features include automatic hardware and
software flow control, selectable TX and RX trigger
levels, and wireless infrared (IrDA) encoder/decoder.
The XR16C850 is available in the 44 pin PLCC and
48 pin TQFP packages. They both provide the
standard Intel Bus mode and PC ISA bus (PC) mode.
The Intel Bus mode is compatible with the ST16C450
and ST16C550 while the PC mode allows connection
to the PC ISA bus.
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
0 ns address hold time (T
AH
)
•
2.97 to 5.5 volt operation
•
Pin to pin compatible to ST16C550, ST16C580,
ST16C650A and TL16C750
•
128-byte Transmit and Receive FIFOs
•
Transmit/Receive FIFO Counters
•
Programmable TX/RX FIFO Trigger Levels
•
Automatic Hardware/Software Flow Control
•
Auto RS-485 half duplex direction support
•
Programmable Xon/Xoff characters
•
Infrared (IrDA) TX and RX Encoder/Decoder
•
Sleep Mode (100 uA stand-by)
APPLICATIONS
•
Battery Operated Electronics
•
Internet Appliances
•
Handheld Terminal
•
Personal Digital Assistants
•
Cellular Phones DataPort
•
Wireless Infrared Data Communications Systems
F
IGURE
1. B
LOCK
D
IAGRAM
RESET
1 2 8 B y te T X F IF O
A 2 :A 0
D 7 :D 0
IO R #
IO R
IO W #
IO W
CS2#
CS1
CS0
IN T
TXRDY#
RXRDY#
D D IS #
BRG
P re s c a le r
PCM O DE#
S1
S2
S3
IR Q A
IR Q B
IR Q C
B a u d R a te G e n e ra to r
PC
M o e to
C O Md1 :
4
D e c o d e L o g ic
X T A L 1 /C L K
XTAL2
In te l o r
P C D a ta
Bus
In te rfa c e
UART
C o n fig u ra tio n
Regs
C T S F lo w
C o n tro l
M o d e m C o n tro l S ig n a ls
R T S F lo w
C o n tro l
T ra n s m itte r
In fra re d
Encoder
TX
DTR#, RTS#
DSR#, CTS#,
C D # , R I#
In fra re d
Decoder
RX
R e c e iv e r
1 2 8 B y te R X F IF O
C ry s ta l O s c /B u ffe r
Exar
Corporation 48720 Kato Road, Fremont CA, 94538
•
(510) 668-7000
•
FAX (510) 668-7017
•
www.exar.com
EXAR [ EXAR CORPORATION ]
