DESCRIPTION
   The XR16C2850 (2850) is a dual universal asynchronous receiver and transmitter (UART). The 2850 provides enhanced UART functions with 128 byte FIFO, automatic RS-485 half duplex control, a modem control interface, and data rates up to 1.5 Mbps. Onboard status registers provide the user with error indications and operational status. System interrupts and modem control features may be tailored by external software to meet specific user requirements. An internal loopback capability allows onboard diagnostics.

FEATURES
• Pin and functionally compatible to ST16C2550,
   software compatible with INS8250, NS16C550
• 1.5 Mbps transmit/receive operation (24 MHz
   Max.).
• 128 byte transmit FIFO to reduce bandwidth requirement of the external CPU.
• 128 byte receive FIFO with error flags to reduce
   bandwidth requirement of the external CPU.
• Independent transmit and receive UART control.
• RS-485 half duplex control.
• Programmable transmit/receive FIFO trigger levels.
• Hardware / software flow control.
• Selectable RTS flow control hysterisis.
• Modem control signals (-CTS, -RTS, -DSR, -DTR,
   -RI, -CD, and software controllable line break).
• Programmable character lengths (5, 6, 7, 8) with
   even, odd, or no parity.
• Infrared receive and transmit encoder/decoder.
• Device identification.
• Crystal or external clock input.
• 460.8 Kbps transmit/receive operation with 7.3728
   MHz crystal or external clock source.