| 摘要 |
A system for enhancing universal serial bus (USB) applications comprises an upstream processor, a downstream processor and a main controller. The upstream processor accepts standard USB signals from a USB host and independently provides responses required by USB specification within the required time frame. The upstream processor also contains storage for descriptors for a device associated with this upstream processor. The main controller obtains the descriptors by commanding the downstream processor, and passes them to the upstream processor. The downstream processor connectable to USB-compliant devices accepts the USB signals from the USB-compliant devices and provides responses required by USB specification within the required time frame. The main controller interconnects the upstream and downstream processors, and provides timing independence between upstream and downstream timing. The main controller also commands the downstream processor to obtain device descriptors independent of the USB host. |
