Low-power USB flash card reader using bulk-pipe streaming with UAS command re-ordering and channel separation

摘要

A flash-card reader improves transmission efficiency by using bulk streaming of multiple pipes. A bulk data-out pipe carries host write data to the card reader and can operate in parallel with a bulk data-in pipe that carries host read data that was read from a flash card attached to the card reader. Status packets do not block data packets since the he status packets are buffered through a separate status pipe, and commands are buffered through a command pipe. Flash data from multiple flash cards are interleaved as separate endpoints that share the bulk data-in pipe. A data in/out streaming state machine controls streaming bulk data through the bulk data-in and data-out pipes, while a status streaming state machine controls streaming status packets through the status pipe. Transaction overhead is reduced using bulk streaming where packets for several commands are combined into the same bulk streams.