Cypress’s FX2LP (CY7C6801x) is one of the smallest footprint MCUs that offer a high-speed USB (480 Mbit/s) device peripheral with built-in PHY (many others lack the PHY!). It contains a 8051 core for bookkeeping and setting up data streams through its hardware multiplexed parallel FIFO interface to/from an external processor, be it MCU, DSP, or FPGA/CPLD.
This is a breadboard-friendly minimal system PCB for CY7C68013 in QFN56 package. It integrates 3.3 V power supply, core clock, reset circuit/button, and I2C EEPROM (the MCU does not have built-in flash). It breaks out all IO pins through 2 rows x 20 pins 0.1″ pitch headers with 0.7″ row spacing.
summivox has shared the board on OSH Park: