The MCP2221 is a USB-to-UART/I2C serial converter which enables USB connectivity in applications that have a UART and I²C interfaces. The device reduces external components by integrating the USB termination resistors and the oscillator needed for USB operation. The MCP2221 also has four GP pins providing miscellaneous functionalities (GPIO, USBCFG, SSPND, Clock Output, ADC, DAC, interrupt detector). Please see our MikroElektronika click board! http://www.mikroe.com/click/usb-i2c