The MAX3420E contains the digital logic and analog circuitry necessary to implement a full-speed USB peripheral compliant to USB specification rev 2.0. A built-in full-speed transceiver features 15kV ESD protection and programmable USB connect and disconnect. An internal SIE (serial-interface engine) handles low-level USB protocol details such as error checking and bus retries. The MAX3420E operates using a register set accessed by an SPI interface that operates up to 26MHz. Any SPI master (microprocessor, ASIC, DSP, etc.) can add USB functionality using the simple 3- or 4-wire SPI interface.