The PL-2551 is a single chip Hi-Speed USB general-purpose device controller. It is designed to provide a solution for users to develop diverse USB related applications with embedded turbo 8032 compliant MCU and internal 16MB ROM. The chip supports up to 16 endpoints. Aside from the endpoint 0, the default control endpoint, the other 15 endpoints can be configured as control, bulk in/out, isochronous in/out, or interrupt in/out endpoints according to the requirement of the desired applications. A centralized data buffer architecture is adopted so that users can develop required functionality with as less limitation as possible. A Programmable DMA (PDMA) controller is provided to perform data transfer between the application and USB interface. The data transfer protocol can be designed using the micro code of the DMA controller and written to the embedded code RAM by firmware. Protocols such as IEEE1284, ATA PIO and DMA mode, CMOS sensor interface etc. have been proven using the PDMA.