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Brandon
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Iron
Re: Nov 27 - Day 2: USB Over a Single Wire Pair
Brandon   11/28/2012 3:16:14 PM
NO RATINGS
I'm not sure if anyone is still montoring this chat, but if so I have a question regarding device powering.  I am having trouble understanding what actually controls the amount of current being delivered on VBUS to any one device.  To provide an example - I am working on a design of a device that has a 4-port hub as the direct connection to the USB host on a PC, and from that there are three devices currently connected.  When all of the devices enumerate as being bus-powered, how much current is actually available from the host?  Does it allow up to 500mA draw regardless of how many devices are actually downstream of the hub, or will it only provide 100mA per downstream device?



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