XR17V254
66MHZ PCI BUS QUAD UART WITH POWER MANAGEMENT SUPPORT
FEBRUARY 2007
REV. 1.0.0
GENERAL DESCRIPTION
• Instrumentation
• Multi-port RS-232/RS-422/RS-485 Cards
• Point-Of-Sales
1
The XR17V254 (V254) is a single chip 4-channel
66MHz PCI (Peripheral Component Interconnect)
UART (Universal Asynchronous Receiver and
FEATURES
Transmitter)
solution,
optimized
for
higher
performance and lower power. The V254 device with
its fifth generation register set is designed to meet the
• High performance 32-bit 66MHz PCI UART
• PCI 3.0 compliance
high
bandwidth
and
power
management
requirements for multi-serial communication ports for
system administration and management. The 32-bit
66MHz PCI interface is compliant with PCI 3.0 and
PCI power management revision 1.1 specifications.
The device provides an upgrade path for Exar’s
33MHz 5V and Universal PCI UART family of
products in a 144-pin LQFP package.
• PCI power management rev. 1.1 compliance
• EEPROM interface for PCI configuration
• 3.3V supply with 5V tolerant non-PCI (serial) inputs
• Data read/write burst operation
• Global interrupt register for all four UART channels
• Up to 8 Mbps serial data rate
The V254 consists of four independent UART
channels, each with set of configuration and
enhanced registers, 64 bytes of Transmit (TX) and
Receive (RX) FIFOs, and a fractional Baud Rate
Generator (BRG). A global interrupt source register
provides a complete interrupt status indication for all
4 channels to speed up interrupt parsing. The V254
device operates at 33/66MHz and features fully
programmable TX and RX FIFO level triggers,
automatic hardware and software flow control, and
automatic RS-485 half duplex direction control output
for software and hardware design simplification.
• Eight multi-purpose inputs/outputs
• A 16-bit general purpose timer/counter
• Sleep mode with wake-up Indicator
• Four independent UART channels controlled with
■ 16C550 compatible register Set
■ 64-byte TX and RX FIFOs with level counters
and programmable trigger levels
■ Fractional baud rate generator
■ Automatic RTS/CTS or DTR/DSR hardware
NOTE 1: Covered by U.S. Patents #5,649,122 and #5,949,787
flow control with programmable hysteresis
APPLICATIONS
■ Automatic Xon/Xoff software flow control
• Remote Access Servers
■ RS-485 half duplex direction control output
with selectable turn-around delay
• Storage Network Management
• Factory Automation and Process Control
■ Infrared (IrDA 1.0) data encoder/decoder
FIGURE 1. BLOCK DIAGRAM OF THE XR17V254
(5V Tolerant
Serial Inputs)
3.3V VCC
UART Channel 0
CLK (upto
66MHz)
64 Byte TX FIFO
TX0, RX0, DTR0#,
UART
Regs
IR
DSR0#, RTS0#,
CTS0#, CD0#, RI0#
TX & RX
ENDEC
RST#
BRG
64 Byte RX FIFO
AD[31:0]
C/BE[3:0]#
FRAME#
IRDY#
UART Channel 1
TRDY#
Device
Configuration
Registers
PCI Local
Bus
Interface
DEVSEL#
STOP#
IDSEL
PERR#
SERR#
PAR
UART Channel 2
INTA#
PME#
TX3, RX3, DTR3#,
DSR3#, RTS3#,
CTS3#, CD3#, RI3#
UART Channel 3
Configuration
Space
Registers
Multi-purpose
Inputs/Outputs
.
MPIO0- MPIO7
16-bit
Timer/Counter
EECK
EEDI
EEDO
EECS
EEPROM
Interface
XTAL1
XTAL2
Crystal Osc/Buffer
TMRCK
GND
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www.exar.com