| 摘要 |
A polling method, apparatus, and system capable to detect the attachment and detachment of Universal Serial Bus (USB) devices in a wireless USB system. A USB hub provides a wired connection to the host, while providing wireless attachment points for its devices. The USB host periodically queries the hub looking for changes in the hub's status register. During each period, the hub sends a polling message through each of its wireless ports, and awaits a response. A peripheral device that wishes to attach to the system responds to the message by sending its unique peripheral address. If a device currently occupies the port, the hub sends out the device's unique assigned address as part of the polling message. If the device is still present, it responds by sending its unique peripheral address. If the host does not receive a response after multiple retries, the device is considered detached. The hub thus determines the status of the ports and updates the appropriate bits in the status register, which is then queried by the host.
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