GENERAL DESCRIPTION
   The XR17L1521 (L152) 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 requirements in communication systems. The global interrupt source register provides a complete interrupt status indication for both channels to speed up interrupt parsing. 

FEATURES
• High Performance DUART
• PCI Bus 2.2 Target Interface Compliance
• 3.3 V PCI Bus Compliant up to 33 MHz Clock
• 5 Volt Tolerant Serial Inputs
• 32-bit PCI Bus Interface with EEPROM Interface
• 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 Half-duplex Control Output with
      Selectable Turn-around Delay (0 to 15 bit-times)
   • Infrared (IrDA 1.0) Data Encoder/Decoder
   • Programmable Data Rate with Prescaler
   • Up to 3.125 Mbps Data Rate at 8X Sampling
• Eight Multi-Purpose Inputs/outputs
• A General Purpose 16-bit Timer/Counter
• Sleep Mode with Automatic Wake-up Indicator
• Same package and pin-out as XR17C152 and
   XR17D152 (14x14x1.0 mm TQFP)

APPLICATIONS
• 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