PORTS Forum

Ports and Interfaces => USB => Topic started by: jb on March 03, 2021, 05:44:15 pm

Title: Draw current from CDP despite claiming 0 mA
Post by: jb on March 03, 2021, 05:44:15 pm

If a device detects that it's connected to a Charging Downstream Port, can it enumerate with maxPower = 0 mA but still draw current, because the CDP over-rules the enumeration?

Title: Re: Draw current from CDP despite claiming 0 mA
Post by: Jan Axelson on March 03, 2021, 09:56:18 pm

bMaxPower specifies how much bus current the device requires. A device that requires bus current but specifies bMaxPower = 0  might enumerate but wouldn't be compliant with the spec.