XR16C2550_07 Datasheet, PDF (1/37 Pages) Exar Corporation – 2.97V TO 5.5V DUART WITH 16-BYTE FIFO

XR16C2550
2.97V TO 5.5V DUART WITH 16-BYTE FIFO
FEBRUARY 2007
REV. 1.0.2
GENERAL DESCRIPTION
The XR16C2550 (2550) is a dual universal
asynchronous receiver and transmitter (UART). The
XR16C2550 is an improved version of the PC16550
UART with higher operating speed and faster access
times. The 2550 provides enhanced UART functions
with 16 byte FIFO’s, a modem control interface, and
data rates up to 4 Mbps. Onboard status registers
provide the user with error indications and
operational status. System interrupts and modem
control features may be tailored by external software
to meet specific user requirements. Independent
programmable baud rate generators are provided to
select transmit and receive clock rates from 50 bps to
4 Mbps. The Baud Rate Generator can be configured
for either crystal or external clock input. An internal
loopback capability allows onboard diagnostics. The
2550 is available in a 44-pin PLCC and 48-pin TQFP
packages. The 2550 is fabricated in an advanced
CMOS process capable of operating from 2.97 volt to
5.5 volt power supply.
APPLICATIONS
• Portable Appliances
• Telecommunication Network Routers
• Ethernet Network Routers
• Cellular Data Devices
• Factory Automation and Process Controls
FEATURES
• 2.97 Volt to 5.5 Volt Operation
• 5 Volt Tolerant Inputs
• Pin-to-pin compatible to Exar’s ST16C2450,
XR16L2550 and XR16L2750
• Pin-to-pin compatible to TI’s TL16C752B on the 48-
TQFP package
• Pin alike XR16C2850 48-TQFP package but
without CLK8/16, CLKSEL and HDCNTL inputs
• 2 independent UART channels
■ Up to 4 Mbps with external clock of 64 MHz
■ Up to 1.5 Mbps data rate with a 24 MHz crystal
frequency
■ 16 byte Transmit FIFO to reduce the bandwidth
requirement of the external CPU
■ 16 byte Receive FIFO with error tags to reduce
the bandwidth requirement of the external CPU
■ 4 selectable Receive FIFO interrupt trigger
levels
■ Modem control signals (CTS#, RTS#, DSR#,
DTR#, RI#, CD#)
■ Programmable character lengths (5, 6, 7, 8)
with even, odd, or no parity
• Crystal oscillator or external clock input
• 48-TQFP and 44-PLCC packages
FIGURE 1. XR16C2550 BLOCK DIAGRAM
A2:A0
D7:D0
IOR#
IOW#
CSA#
CSB#
INTA
INTB
TXRDYA#
TXRDYB#
RXRDYA#
RDRXYB#
Reset
8- bit Data
Bus
Interface
*All inputs are 5V tolerant
UART Channel A
UART
Regs
BRG
16 Byte TX FIFO
TX & RX
16 Byte RX FIFO
UART Channel B
( same as Channel A )
Crystal Osc / Buffer
2.97 V to5.5V
GND
TXA , RXA, DTRA#,
DSRA#, RTSA#,
DTSA#, CDA#, RIA#,
OP2A#
TXB, RXB, DTRB#,
DSRB#, RTSB#,
CTSB#, CDB#, RIB#,
OP2B#
XTAL1
XTAL2
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • [phone] • FAX [phone] • www.exar.com