xr
NOVEMBER 2005
XR16C2850
2.97V TO 5.5V DUAL UART WITH 128-BYTE FIFOS
REV. 2.1.3
GENERAL DESCRIPTION
The XR16C2850
1
(2850) is an enhanced dual
universal asynchronous receiver and transmitter
(UART). Enhanced features include 128 bytes of TX
and RX FIFOs, programmable TX and RX FIFO
trigger level, FIFO level counters, automatic (RTS/
CTS) hardware and (Xon/Xoff) software flow control,
automatic RS-485 half duplex direction control output
and data rates up to 6.25 Mbps at 5V and 8X
sampling clock.
Onboard status registers provide the user
with operational status and data error flags. An internal
loopback capability allows system diagnostics.
The 2850
has a full modem interface and can operate at 2.97V
to 5.5V and is pin-to-pin compatible to Exar’s
ST16C2550 and XR16C2750 except the 48-TQFP
package. The 2850 register set is compatible to the
industry standard ST16C2550 and is available in 48-
pin TQFP and 44-pin PLCC packages.
N
OTE
:
1 Covered by U.S. Patent #5,649,122 and #5,949,787
FEATURES
Added feature in devices with a top mark date code of
"F2 YYWW" and newer:
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5V tolerant inputs
0 ns address hold time (T
AH
)
•
Pin-to-pin compatible and functionally compatible to
Exar’s ST16C2550 and XR16L2750 and TI’s
TL16C752B in the 48-TQFP package
•
Pin-alike Exar’s XR16L2750 and ST16C2550 48-
TQFP package but with additional CLK8/16,
CLKSEL and HDCNTL inputs
•
Two independent UART channels
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APPLICATIONS
•
Portable Appliances
•
Telecommunication Network Routers
•
Ethernet Network Routers
•
Cellular Data Devices
•
Factory Automation and Process Controls
Register set compatible to 16C550
Up to 6.25 Mbps at 5V, and 4 Mbps at 3.3V
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
Auto RS-485 Half-duplex Direction Control
Wireless Infrared (IrDA 1.0) Encoder/Decoder
Full modem interface
•
Device Identification and Revision
•
Crystal oscillator or external clock input
•
Industrial and commercial temperature ranges
•
48-TQFP and 44-PLCC packages
F
IGURE
1. XR16C2850 B
LOCK
D
IAGRAM
A2:A0
D7:D0
IOR#
IOW#
CSA#
CSB#
INTA
INTB
TXRDYA#
TXRDYB#
RXRDYA#
RXRDYB#
HDCNTL#
CLKSEL
CLK8/16
Reset
8-bit Data
Bus
Interface
UART Channel A
UART
Regs
BRG
128 Byte TX FIFO
TX & RX
IR
ENDEC
2.97V to 5.5V VCC
GND
TXA, RXA, DTRA#,
DSRA#, RTSA#,
DTSA#, CDA#, RIA#,
OP2A#
128 Byte RX FIFO
TXB, RXB, DTRB#,
DSRB#, RTSB#,
CTSB#, CDB#, RIB#,
OP2B#
XTAL1
XTAL2
UART Channel B
(same as Channel A)
Crystal Osc/Buffer
Exar
Corporation 48720 Kato Road, Fremont CA, 94538
•
(510) 668-7000
•
FAX (510) 668-7017
•
www.exar.com
EXAR [ EXAR CORPORATION ]
