Exar Corporation 48720 Kato Road, Fremont CA, 94538 (510) 668-7000 FAX (510) 668-7017 www.exar.com
XR16M752/XR68M752
HIGH PERFORMANCE DUART WITH 64-BYTE FIFO
JUNE 2009
REV. 1.1.1
GENERAL DESCRIPTION
The XR16M752/XR68M7521 (M752) is a high
performance dual universal asynchronous receiver
and transmitter (UART) with 64 byte TX and RX
FIFOs. The M752 operates from 1.62 to 3.63 volts. It
is pin-to-pin and software compatible to the
TL16C752B and SC16C752B, but with additional
features such as a programmable fractional baud rate
generator, automatic RS-485 half-duplex direction
control, infrared mode and 8X and 4X sampling rate.
The standard features include 16 selectable TX and
RX FIFO trigger levels, automatic hardware (RTS/
CTS) and software (Xon/Xoff) flow control, and a
complete modem interface. Onboard registers
provide the user with operational status and data
error flags. An internal loopback capability allows
system diagnostics. Each channel is independently
programmable for data rates up to 16 Mbps at 3.3V
with a 4X sampling rate. The XR68M752 has an
additional 16/68# pin to select between the Intel and
Motorola bus interface. The M752 is available in the
48-pin TQFP, 32-pin QFN and 49-pin STBGA
packages.
NOTE: 1 Covered by U.S. Patent #5,649,122
APPLICATIONS
Portable Appliances
Telecommunication Network Routers
Ethernet Network Routers
Cellular Data Devices
Factory Automation and Process Controls
FEATURES
1.62 to 3.6 Volt Operation
Pin-to-pin and software compatible to TI’s
TL16C752B and Philips’ SC16C752B in the 48-
TQFP package
Two independent UART channels
■ Data rate of up to 16 Mbps at 3.3 V
■ Data rate of up to 12.5 Mbps at 2.5 V
■ Data rate of up to 8 Mbps at 1.8 V
■ Fractional Baud Rate Generator
■ Data sampling rates of 16X, 8X and 4X
■ Transmit and Receive FIFOs of 64 bytes
■ Programmable TX and RX FIFO Trigger Levels
■ Automatic Hardware (RTS/CTS) Flow Control
■ Automatic Software (Xon/Xoff) Flow Control
■ Halt and Resume Transmission Control
■ Automatic
RS-485
Half-duplex
Direction
Control Output via RTS#
■ Wireless Infrared (IrDA 1.0) Encoder/Decoder
■ Automatic sleep mode
■ Full modem interface
Crystal oscillator (up to 24MHz) or external clock
(up to 64MHz) input
48-TQFP, 32-QFN and 49-STBGA packages
FIGURE 1. XR16M752 BLOCK DIAGRAM
XTAL1
XTAL2
Crystal Osc/Buffer
TXA, RXA, DTRA#,
DSRA#, RTSA#,
DTSA#, CDA#, RIA#,
OP2A#
8-bit Data
Bus
Interface
UART Channel A
64 Byte TX FIFO
BRG
IR
ENDEC
TX & RX
UART
Regs
1.62 to 3.63 Volt VCC
GND
TXB, RXB, DTRB#,
DSRB#, RTSB#,
CTSB#, CDB#, RIB#,
OP2B#
UART Channel B
(same as Channel A)
A2:A0
D7:D0
CSA# (CS#)
CSB# (A3)
INTA (IRQ#)
INTB (NC)
IOW# (R/W#)
IOR# (NC)
Reset/Reset#
TXRDYA#
TXRDYB#
RXRDYA#
RXRDYB#
64 Byte RX FIFO
16/68#