
Exar Corporation 48720 Kato Road, Fremont CA, 94538 (510) 668-7000 FAX (510) 668-7017 www.exar.com
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XR17D154
UNIVERSAL (3.3V AND 5V) PCI BUS QUAD UART
AUGUST 2005
REV. 1.2.2
GENERAL DESCRIPTION
The XR17D1541 (D154) is a quad PCI Bus Universal
Asynchronous Receiver and Transmitter (UART) with
same package and pin-out as the Exar XR17C158,
XR17D158 and XR17C154. The device is designed
to meet today’s 32-bit PCI Bus and high bandwidth
requirement in communication systems. The global
interrupt source register provides a complete interrupt
status indication for all 4 channels to speed up
interrupt parsing. Each UART is independently
controlled and has its own 16C550 compatible 5G
register set, transmit and receive FIFOs of 64 bytes,
fully programmable transmit and receive FIFO trigger
levels, transmit and receive FIFO level counters,
automatic hardware flow control with programmable
hysteresis,
automatic
software
(Xon/Xoff)
flow
control, IrDA (Infrared Data Association) encoder/
decoder, 8 multi-purpose inputs/outputs and a 16-bit
general purpose timer/counter.
NOTE: 1 Covered by U.S. Patents #5,649,122, #5,949,787
APPLICATIONS
Universal Form Factor PCI Bus Add-in Card
Remote Access Servers
Ethernet Network to Serial Ports
Network Management
Factory Automation and Process Control
Point-of-Sale Systems
Multi-port RS-232/RS-422/RS-485 Cards
FEATURES
High Performance Quad PCI UART
Universal PCI Bus Buffers - Auto-sense 3.3V or 5V
Operation
32-bit PCI Bus 2.3 Target Signalling Compliance
A Global Interrupt Source Register for all 4 UARTs
Data Transfer in Byte, Word and Double-word
Data Read/Write Burst Operation
Each UART is independently controlled with:
■ 16C550 Compatible 5G Register Set
■ 64-byte Transmit and Receive FIFOs
■ Transmit and Receive FIFO Level Counters
■ Automatic RTS/CTS or DTR/DSR Flow Control
■ Automatic Xon/Xoff Software Flow Control
■ Automatic RS485 Half-duplex Control Output
with Selectable Turn-around Delay
■ Infrared (IrDA 1.0) Data Encoder/Decoder
■ Programmable Data Rate with Prescaler
■ Up to 6.25 Mbps Serial Data Rate at 8X
Eight Multi-Purpose Inputs/outputs
General Purpose 16-bit Timer/Counter
Sleep Mode with Automatic Wake-up
EEPROM Interface for PCI Configuration
Same package and pin-out as the XR17D158,
XR17C158 and XR17C154 (20x20x1.4mm 144-
LQFP)
FIGURE 1. BLOCK DIAGRAM
TMRCK
Device
Configuration
Registers
XTAL1
XTAL2
Crystal Osc/Buffer
UART Channel 0
TX0, RX0, DTR0#,
DSR0#, RTS0#,
CTS0#, CD0#, RI0#
PCI Local
Bus
Interface
Configuration
Space
Registers
.
MPIO0- MPIO7
Multi-purpose
Inputs/Outputs
TX3, RX3, DTR3#,
DSR3#, RTS3#,
CTS3#, CD3#, RI3#
UART Channel 3
UART Channel 2
UART Channel 1
16-bit
Timer/Counter
EECK
EEDI
EEDO
EECS
EEPROM
Interface
64 Byte TX FIFO
64 Byte RX FIFO
BRG
IR
ENDEC
TX & RX
UART
Regs
VCC (Core
Logic)
GND
ENIR
CLK (33MHz)
RST#
AD[31:0]
C/BE[3:0]#
PAR
FRAME#
IRDY#
TRDY#
DEVSEL#
STOP#
IDSEL
PERR#
SERR#
INTA#
3.3V or 5V
(PCI VI/O
Power Supply)