The XR16C854/854D1 (854) is an enhanced quad Universal Asynchronous Receiver and Transmitter (UART) each with 128 bytes of transmit and receive FIFOs, transmit and receive FIFO counters and trigger levels, automatic hardware and software flow control, and data rates of up to 2 Mbps. Each UART has a set of registers that provide the user with operating status and control, receiver error indications, and modem serial interface controls. System interrupts may be tailored to meet design requirements. An internal loopback capability allows onboard diagnostics. The 854 is available in 64-pin TQFP, 68-pin PLCC and 100-pin QFP packages. The 64-pin package only offers the 16 mode interface, but the 68 and 100 pin packages offer an additional 68 mode interface which allows easy integration with Motorola processors. The