XR21V1412 2-CH FULL-SPEED USB UART DECEMBER 2013 REV. 1.3.0 FEATURES GENERAL DESCRIPTION USB 2.0 Compliant, Full-Speed (12 Mbps) The XR21V1412 (V1412) is an enhanced 2-channel Universal Asynchronous Receiver and Transmitter Supports USB suspend, resume and remote (UART) with a USB interface. The USB interface is wakeup operations fully compliant to Full Speed USB 2.0 specification 5 kV HBM ESD protection on USB data pins that supports 12 Mbps USB data transfer rate. The 2 kV HBM ESD protection on all other pins USB interface also supports USB suspend, resume and remote wakeup operations. Enhanced Features of each UART The V1412 operates from an internal 48MHz clock UART data rates up to 12 Mbps therefore no external crystal/oscillator is required as Fractional Baud Rate Generator in previous generation UARTs. With the fractional 128 byte TX FIFO baud rate generator, any baud rate can accurately be 384 byte RX FIFO generated using the internal 48MHz clock. 7, 8 or 9 data bits The large 128-byte TX FIFO and 384-byte RX FIFO 1 or 2 stop bits of the V1412 helps to optimize the overall data throughput for various applications. If required, the Odd, even, mark, space or no parity multidrop mode and automatic RS-485 half-duplex Automatic Hardware (RTS/CTS or DTR/DSR) direction control feature further simplifies typical Flow Control multidrop RS-485 applications. Automatic Software (Xon/Xoff) Flow Control The V1412 operates from a single 2.97 to 3.63 volt Multidrop mode power supply and has 5V tolerant inputs. The V1412 Auto RS-485 Half-Duplex Control is available in a 32-pin QFN package. Half-Duplex mode WHQL certified software drivers for Windows 2000, Selectable GPIO or Modem I/O XP, Vista, 7, 8, and CE, as well as Linux and Mac are Internal 48 MHz clock supported for the XR21V1412. Single 3.3V power supply APPLICATIONS 5V tolerant GPIO inputs Portable Appliances 32-pin QFN package External Converters (dongles) Virtual COM Port WHQL certified drivers Battery-Operated Devices Windows 2000, XP, Vista, Win7 and Win8 Cellular Data Devices Windows CE 4.2, 5.0, 6.0, 7.0 Factory Automation and Process Controls Linux Industrial applications Mac Exar Corporation 48720 Kato Road, Fremont CA, 94538 (510) 668-7000 FAX (510) 668-7017 www.exar.com XR21V1412 2-CH FULL-SPEED USB UART REV. 1.3.0 FIGURE 1. XR21V1412 BLOCK DIAGRAM 128-byte TXA TX FIFO Fractional 3.3V VCC BRG GND 384-byte RXA RX FIFO GPIOA5/RTSA /RS485A Internal GPIOA4/CTSA GPIOA3/DTRA Status and GPIOs/ USB Slave USBD+ Control Modem IO GPIOA2/DSRA Interface USBD- Registers GPIOA1/CDA GPIOA0/RIA UART Channel A 2 128-byte I C SDA TXB TX FIFO Fractional Interface SCL BRG 384-byte RXB RX FIFO GPIOB5/RTSB /RS485B GPIOB4/CTSB Internal GPIOB3/DTRB Status and GPIOs/ Internal Control GPIOB2/DSRB Modem IO 48MHz GPIOB1/CDB Registers Oscillator GPIOB0/RIB UART Channel B 2