HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Comment
Brandon
User Rank
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?



Partner Zone
Latest Analysis
Former DARPA official and Google executive Dr. Kaigham Gabriel believes sensor companies think too much like suppliers and need to bring their products closer to the consumer.
One way to keep a Formula One racing team moving at breakneck speed in the pit and at the test facility is to bring CAD drawings of the racing vehicleís parts down to the test facility and even out to the track.
Most of us would just as soon step on a cockroach rather than study it, but thatís just what researchers at UC Berkeley did in the pursuit of building small, nimble robots suitable for disaster-recovery and search-and-rescue missions.
Engineers at Festo were inspired by how a caterpillar builds its cocoon when designing its new 3D Cocooner printer.
Design engineers need to prepare for a future in which their electronic products will use not just one or two, but possibly many user interfaces that involve touch, vision, gestures, and even eye movements.
More:Blogs|News
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6 |  7 | 8 | 9


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Course June 28-30:
Sponsored by Proto Labs
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Technology Marketplace

Copyright © 2016 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service