GENERAL DESCRIPTION
   The XR17D1521 (D152) is a monolithic dual PCI Bus Universal Asynchronous Receiver and Transmitter (UART) in Exar’s PCI Bus UART family. The device is designed to meet today’s 32-bit PCI Bus and high bandwidth requirement in communication systems.

FEATURES
● High Performance Dual PCI UART
● Universal PCI Bus Buffers - Auto-sense 3.3V and
   5V Operation
● 32-bit PCI Bus 2.3 Target Signalling Compliance
● A Global Interrupt Source Register for both 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
   ■ Programmable TX and RX FIFO Trigger Level
   ■ Automatic RTS/CTS or DTR/DSR Flow Control
   ■ Automatic Xon/Xoff Software Flow Control
   ■ Automatic RS485 HDX Control Output with
      Selectable Turn-around Delay
   ■ Infrared (IrDA 1.0) Data Encoder/Decoder
   ■ Programmable Data Rate with Prescaler
   ■ Up to 6.25 Mbps Data Rate at 8X Sampling
● Eight Multi-Purpose Inputs/outputs
● A General Purpose 16-bit Timer/Counter
● Sleep Mode with Automatic Wake-up
● EEPROM Interface for PCI Configuration
● Same package and pin-out as the XR17C152
   (14x14x1.0 mm TQFP)

APPLICATIONS
● Universal PCI Bus Add-in Card
● Network Management
● Factory Automation and Process Control
● Ethernet Network to Serial Ports
● Point-of-Sale Systems
● Multi serial ports RS-232/RS-422/RS-485 Cards