The XR20V2170 (2170) and XR20V2172 (2172) are high performance single and dual channel universal asynchronous receiver and transmitters (UART) with a selectable I²C/SPI slave interface. These devices are software compatible with the industry standard 16550 UART, but with some additional enhanced features such as larger 64-byte TX/RX FIFOs, automatic hardware and software flow control, programmable fractional baud rate generator, 8X and 4X sampling rates and an integrated RS-232 transceiver.