Pipe regions PIPE0 to PIPEe (or endpoint regions) are allocated in a packet buffer, registers in which are set page sizes MPS0 to MPe (maximum packet size) and numbers of pages BP0 to BPe for the pipe regions are provided, and data is transferred between pipe regions and endpoints, region sizes RS0 to RSe of the pipe regions being set by the page sizes and numbers of pages. The page sizes and numbers of pages are set in registers that are used in common during both host operation and peripheral operation in accordance with the USB on-the-go standard. Transfer condition information such as transfer types TT0 to TTe is set in the registers, transactions with respect to the endpoints are automatically issued, and data is automatically transferred. Pipe regions are allocated in the packet buffer during host operation whereas endpoint regions are allocated during peripheral operation.