The XR20V21721 (V2172) is a high performance two channel universal asynchronous receiver and transmitter (UART) with 64 byte TX and RX FIFOs, a selectable I2C/SPI slave interface and RS232 transceiver. The V2172 operates from 3.3 to 5.5 volts. The enhanced features in the V2172 include a programmable fractional baud rate generator, an 8X and 4X sampling rate that allows for a maximum baud rate of 1 Mbps at 3.3V. The standard features include 16 selectable TX and RX FIFO trigger levels, automatic hardware (RTS/CTS) and software (Xon/ Xoff) flow control, and a complete modem interface. Onboard registers provide the user with operational status and data error flags. An internal loopback capability allows system diagnostics. The V2172 is available in the 64-pin QFN.