Device-side controller, host-side controller, communication controller, USB system, and packet communications method

摘要

A host-side control section of a host-side controller, when having received a SOF packet transmitted from a host to a device, avoids transmission of the received SOF packet to a device side. A device-side control section of a device-side controller transmits a SOF packet to the device at a predetermined interval after connection between the host and the device has been established. This eliminates the need for SOF packet transmission between the controllers. Thus, a communication bandwidth between the controllers of low communication speeds can be used only for packets other than the SOF packet. This increases communication efficiency of these other packets.