The XR16L25501 (L2550) is a dual universal asynchronous receiver and transmitter (UART). The XR16L2550 is an improved version of the ST16C2550 UART with lower operating voltages and 5 volt tolerant inputs. The L2550 provides enhanced UART functions with 16 byte FIFOs, a modem control interface and data rates up to 4 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. Independent programmable baud rate generators are provided to select transmit and receive clock rates up to 3.125 Mbps. The Baud Rate Generator can be configured for either crystal or external clock input. An internal loopback capability allows onboard diagnostics. The L2550 is available in a 44-pin PLCC, 48-pin TQFP and 32-pin QFN packages. The L2550 is fabricated in an advanced CMOS process.