The XR16C28501 (2850) is an enhanced dual universal asynchronous receiver and transmitter (UART). Enhanced features include 128 bytes of TX and RX FIFOs, programmable TX and RX FIFO trigger level, FIFO level counters, automatic (RTS/CTS) hardware and (Xon/Xoff) software flow control, automatic RS485 half duplex direction control output and data rates up to 6.25 Mbps at 5V and 8X sampling clock. Onboard status registers provide the user with operational status and data error flags. An internal loopback capability allows system diagnostics. The 2850 has a full modem interface and can operate at 3.3 V or 5 V and is pin-to-pin compatible to Exar's ST16C2550 and XR16C2750 except the 48-TQFP package. The 2850 register set is compatible to the industry standard ST16C2550 and is available in 48pin TQFP 44-pin PLCC and 40-pin PDIP packages. ,