XR16L2552 Datasheet | Exar

DESCRIPTION The XR16L2552 (L2552) is a dual universal asynchronous receiver and transmitter (UART) with 5 volt tolerant inputs. The XR16L2552 is an improved version of the ST16C2552 UART with lower operating voltages and 5 volt tolerant inputs. The L2552 provides enhanced UART functions with 16 byte TX and RX FIFOs, automatic hardware (RTS/CTS) and software (Xon/Xoff) flow control, and a plete modem control interface. Onboard status registers provide the user with error indications and operational status. Indepedendent programmable baud rate generators are provided to select transmit and receive clock rates up to 3.125Mbps. An internal loop-back capability allows onboard diagnostics. The L2552 provides block mode data transfers (DMA) through FIFO controls. DMA transfer monitoring is provided through the signals TXRDY# and RXRDY#. An Alternate Function Register provides the user with the ability to write the control registers for both UARTs concurrently and selection of the Multi-Function output (Baudout#, OP2#, or RXRDY#). NOTE: 1 Covered by U.S. Patent #5,649,122. FEATURES - 2.25 to 5.5 Volt Operation - 5 Volt Tolerant Inputs - Pin-to-pin and functionally patible to National PC16552 - Pin-to-pin patible to Exar’s ST16C2552, XR16L2752 and XR16C2852 in the 44-PLCC - 2 Independent UART Channels - - - - - - - - - - - APPLICATIONS - Portable Appliances - Telemunication Network Routers - Ethernet Network Routers - Cellular Data Devices - Factory Automation and Process Controls FIGURE 1. XR16L2552 BLOCK DIAGRAM Up to 3.125Mbps with external clock of 50 MHz Register Set patible to 16C550 16 byte Transmit FIFO to reduce the bandwidth requirement of the external CPU 16 byte Receive FIFO with error tags to reduce the bandwidth requirement of the external CPU 4 selectable RX FIFO Trigger Levels Automatic RTS/CTS hardware flow control Automatic Xon Xoff software flow control Wireless infrared encoder/decoder Full Modem Interface (CTS#, RTS#, DSR#, DTR#, RI#, CD#)...