Communication system realizing USB communications between a host computer and its peripheral device and a communication controller transmitting a USB signal under the USB standard

摘要

A two-way transmission system of the present invention is arranged in such a manner that, when a host-side controller confirms the receipt of an IN packet from a USB host, the host-side controller transfers the IN packet to a function-side controller, and receives a DATA packet from the function side. The received DATA packet is temporarily stored in a FIFO. At the time of the receipt of the IN packet again, the host-side controller supplies, to the USB host, the DATA packet stored in the FIFO.