Change the values in configuration descriptor for the Self-powered hub for CY7C66113

Question: How does the hub handle the GetStatus requests by changing the values in configuration descriptor (bmAttributes=self-powered and MaxPower=0)?

 

Answer:

In order to configure the part as a self powered device, does not effect how the hub responds to the any USB requests . The hub will handle the Get_Staus request the same way as if it were a bus powered device. Setting the self-powere bit in bmAttributes field lets the host know that the device is a self powered device and does not rely on the host for power.

In self powered hubs you MUST implement overcurrent protection (external circuitry) to limit the downstream ports from drawing more than 500 mA.