| 摘要 |
A system for a universal serial bus (USB) device to perform power configuration to operate with a USB host. A connection to the USB host is enabled. Then a high-power configuration is reported to the USB host and successful enumeration by the USB host is monitored for. If such enumeration is not forthcoming within a preset time, the connection to the USB host is disabled and re-enabled, and a low-power configuration is then reported to the USB host. Optionally, the system can further ramp up power usage until a preset high-power configuration is reached, or until there is voltage sag on the VBUS and then either ramp power usage back down or measure the sag and set to a calculated power usage.
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