
Exar
Corporation 48720 Kato Road, Fremont CA, 94538
(510) 668-7000
FAX (510) 668-7017
www.exar.com
xr
XR16L2752
2.25V TO 5.5V DUART WITH 64-BYTE FIFO
AUGUST 2004
GENERAL DESCRIPTION
REV. 1.2.0
The XR16L2752
1
(2752) is a low voltage dual
universal asynchronous receiver and transmitter
(UART) with 5 Volt tolerant inputs. The device
operates from 2.25 to 5.5 Volt supply range and is
pin-to-pin compatible to Exar’s ST16C2552 and
XR16C2852. The 2752 register set is compatible to
the ST16C2552 and the XR16C2852 enhanced
features. It supports the Exar’s enhanced features of
64 bytes of TX and RX FIFOs, programmable FIFO
trigger level and FIFO level counters, automatic
hardware (RTS/CTS) and software flow control,
automatic RS-485 half duplex direction control output
and a complete modem interface. Onboard registers
provide the user with operational status and data
error flags. An internal loopback capability allows
system diagnostics. Independent programmable
baud rate generators are provided in each channel to
select data rates up to 6.25 Mbps at 5 Volt and 8X
sampling. The 2752 is available in the 44-pin PLCC
package.
N
OTE
:
1 Covered by U.S. Patent #5,649,122 and #5,949,787
APPLICATIONS
Portable Appliances
Telecommunication Network Routers
Ethernet Network Routers
Cellular Data Devices
Factory Automation and Process Controls
FEATURES
2.25 to 5.5 Volt Operation
5 Volt Tolerant Inputs
Pin-to-pin compatible to Exar’s ST16C2552 and
XR16C2852
Larger FIFO version of PC16C552
Two independent UART channels
■
Reg set compatible to 16C2552 and 16C2852
■
Up to 6.25 Mbps at 5 Volt, 4 Mbps at 3.3 Volt
and 3 Mbps at 2.5 Volt with 8X sampling rate
■
Transmit and Receive FIFOs of 64 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
■
Automatic
RS-485
Control Output via RTS#
■
Wireless Infrared (IrDA 1.0) Encoder/Decoder
■
Automatic sleep mode
■
Full modem interface
Alternate Function Register
Device Identification and Revision
Crystal oscillator or external clock input
Industrial and commercial temperature ranges
44-PLCC package
Half-duplex
Direction
F
IGURE
1. XR16L2752 B
LOCK
D
IAGRAM
MFA#
(OP2A#,
BAUDOUTA#, or
RXRDYA#)
MFB#
(OP2B#,
BAUDOUTB#, or
RXRDYB#)
XTAL1
XTAL2
CTS#A/B, RI#A/B,
CD#A/B, DSR#A/B
Crystal Osc/Buffer
TXA (or TXIRA)
8-bit Data
Bus
Interface
UART Channel A
64 Byte TX FIFO
64 Byte RX FIFO
BRG
IR
ENDEC
TX & RX
UART
Regs
2.25 V to 5.5 V VCC
GND
*5 Volt Tolerant Inputs
(Except External Clock Input)
2752BLK
UART Channel B
(same as Channel A)
A2:A0
D7:D0
IOR#
CS#
CHSEL
INTA
INTB
IOW#
Reset
TXRDYA#
TXRDYB#
RXA (or RXIRA)
Modem Control Logic
DTR#A/B, RTS#A/B
TXB (or TXIRB)
RXB (or RXIRB)