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
Here's a variety of views into the complex production processes at Santa's factory. Happy Holidays!
The Beam Store from Suitable Technologies is managed by remote workers from places as diverse as New York and Sydney, Australia. Employees attend to store visitors through Beam Smart Presence Systems (SPSs) from the company. The systems combine mobility and video conferencing and allow people to communicate directly from a remote location via a screen as well as move around as if they are actually in the room.
Thanks to 3D printing, some custom-made prosthetic limbs, and a Lego set, one lucky dog and a tortoise has learned new tricks.
An MIT research team has invented what they see as a solution to the need for biodegradable 3D-printable materials made from something besides petroleum-based sources: a water-based robotic additive extrusion method that makes objects from biodegradable hydrogel composites.
With Radio Shack on the ropes, let's take a memory trip through the highlights of Radio Shack products.
More:Blogs|News
Design News Webinar Series
12/11/2014 8:00 a.m. California / 11:00 a.m. New York
12/10/2014 8:00 a.m. California / 11:00 a.m. New York
11/19/2014 11:00 a.m. California / 2:00 p.m. New York
11/6/2014 11:00 a.m. California / 2:00 p.m. New York
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  |  67


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.
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service