usb communicatioons

Posted on 2012-03-17
Last Modified: 2012-03-17
I would like to write a java routine to send and receive from a usb port.  I have been looking at several sites and it appears to more than a trivial task.  I did run into this response to the question on a site and am curious about the statement concerning mounting it and writing to it like a drive.  Anyone have any insite on this approach and maybe a little explanation as to how to do it?

The following is the posting from the other site:

if you are looking to directly build something in low level you can see for information about specs...

If you want some examples of code you can look at ... It's in C though.

If you just want to communicate with the USB in linux, you can just have linux mount it and write to it as a regular drive without having to deal with all the other stuff...
Question by:sargent240
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 5
  • 3
LVL 83

Accepted Solution

Dave Baldwin earned 500 total points
ID: 37733777
USB is a network interface, not just a port.  Most devices require low level drivers.  Generally speaking, I don't believe java is suited to that.  So for most devices, you need to talk to the driver and not the USB 'port'.  If it 'looks' like a disk drive to Linux, you can address it that way.

Author Comment

ID: 37733782
Your saying it does not look like a disk drive, right?

Author Comment

ID: 37733785
I'm trying to control a music keyboard with a computer and can do it with the rs232 port.  When I plug in the usb to midi cable "midi1" appears in the dev directory.
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!


Author Comment

ID: 37733802
Can you tell me what value there is in the "midi1" entry in the /dev directory when I plug in the usb to midi cable if any?
LVL 83

Expert Comment

by:Dave Baldwin
ID: 37733816
I suggest you try to send your data to the 'midi1' device like you would a file.  That would be standard practice in Linux.  Open, read, write.  You should get the same responses as from your RS-232 version I would think.  Just a different interface.

Author Closing Comment

ID: 37733864
Again Thanks.

Author Comment

ID: 37733875
I have one other question and I will open a new question if you like, but how is the baud rate controlled if it is handled like a file?
LVL 83

Expert Comment

by:Dave Baldwin
ID: 37733976
Midi only operates at 31.5 kBaud as far as I know.  You don't have to set it for a USB MIDI interface.  This seems to be the best Linux MIDI resource I can find at the moment.  Many older links for this subject are dead.

Featured Post

 Database Backup and Recovery Best Practices

Join Percona’s, Architect, Manjot Singh as he presents Database Backup and Recovery Best Practices (with a Focus on MySQL) on Thursday, July 27, 2017 at 11:00 am PDT / 2:00 pm EDT (UTC-7). In the case of a failure, do you know how long it will take to restore your database?

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Whether you’re a college noob or a soon-to-be pro, these tips are sure to help you in your journey to becoming a programming ninja and stand out from the crowd.
In this post we will learn how to make Android Gesture Tutorial and give different functionality whenever a user Touch or Scroll android screen.
This theoretical tutorial explains exceptions, reasons for exceptions, different categories of exception and exception hierarchy.
With the power of JIRA, there's an unlimited number of ways you can customize it, use it and benefit from it. With that in mind, there's bound to be things that I wasn't able to cover in this course. With this summary we'll look at some places to go…
Suggested Courses

635 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question