The XR16C8721 (872) is a dual universal asynchronous receiver and transmitter (UART) with a 1284 bi-directional parallel port and ISA Bus Plug-and-Play (PnP) interface. The PnP interface supports auto configuration for desktop and embedded PC computers. The host bus interface can also be configured to manually support standard PC addresses COM1-4 and LPT1-2. The parallel port is compatible to IEEE 1284 specification and supports Compatible Centronics, Extended Capability (ECP) and Enhanced Parallel Port (EPP) protocols. The UARTs are software compatible to industry standard 16C550 and include enhanced features of 128 bytes of transmit and receive FIFOs, programmable transmit and receive FIFO trigger levels, transmit and receive FIFO counters, IrDA (Infrared Data Association) encoder/decoder, automatic RTS/CTS hardware flow control with selectable hysteresis and automatic software (Xon/Xoff) flow control. On board status registers provide interrupt priorities, receive data errors and modem status. Each channel has a programmable baud rate generator to provide data rates up to 460.8Kbps. The bidirectional parallel port can be configured as a general purpose input/output interface or connected to a printer or portable storage devices. The 872 operates on a single +5V and +3.3 power supply. It is available in a small 100pin QFP package and offers commercial and industrial temperature ranges. The chip is fabricated in an advanced CMOS process to reduce power consumption.