HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Comment
Christian Légaré
User Rank
Blogger
Re: Nov 28 - Day 3: Understanding the USB Protocol
Christian Légaré   11/28/2012 3:06:12 PM
NO RATINGS
Can you achieve a overall sampling rate of 100Hz for up to 32 USB FS devices connected, when the payload is 4 floats per device. Could this be achieve with HID/Joystick type class, or should I go directly with a custom class??

 

We will have to do the math. First, HID is the right class to use, because it is peioritized by the Host.

(Your 4 floats are 64 bits each? this would mean 32 bytes per transfer)

Second, let's look at the Full Spee table for Interrupt transfer using 32 bytes transfer and see the maximum throughput.

 

At 100Hz, that would mean once every 10 frames. Or stated otherwise, that would mean you can server 3.2 device per frame and have covers the 32 devices in 10 frames.



Partner Zone
Latest Analysis
Businesses cutting across industries are increasingly making use of portable display stands in the UK for marketing.
XYZ, Rabbit, and Disney innovate on the 3d printer in different ways -- from price point to using materials such as yarn.
Materials engineer Dave Palmer shares his top advice for new engineering students; he wishes someone would have given him these tips.
Programs to boost domestic manufacturing combined with technological advances are bringing production back to the US.
Google's Project Tango is in its second iteration, this time taking the form of a tablet. Join us as we unravel the new goodies that Google has packed into the Project Tango Tablet.
More:Blogs|News
Design News Webinar Series
7/23/2014 11:00 a.m. California / 2:00 p.m. New York
7/17/2014 11:00 a.m. California / 2:00 p.m. New York
6/25/2014 11:00 a.m. California / 2:00 p.m. New York
5/13/2014 10:00 a.m. California / 1:00 p.m. New York / 6:00 p.m. London
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Sep 8 - 12, Get Ready for the New Internet: IPv6
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6


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 Class: September 30 - October 2
Sponsored by Altera
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