Thread: Direct USB manipulation

  1. #1
    Registered User
    Join Date
    Nov 2010

    Direct USB manipulation

    My problem is im trying to communicate with a device that does not follow the USB specification. Here is the protocol it uses (SAE J1850 Description, Electrical Interface Bus) I am interested in the 10.4Kbps Variable Pulse Width (VPW) single wire approach on the link's page. I was wondering how i would go about detecting the device, and then how i would communicate with it using a USB end connected to a computer, and the other end connected with the ground wire, one data wire, and the power wire. Reading data should be fairly straightforward but if there is something i am not aware of, please let me know.

    I would prefer a operating system independent solution, but if i had to choose an OS, I would prefer a Windows solution.

    And how would i implement the newer standard protocol ISO 15765 CAN which has a high and low wire coming from the device. I assume that it would be just like communicating with a USB device since there are two wires on each. I could probably figure this one out eventually but i would like to avoid any trouble i can.

    I am a proficient C++ programmer, but not an expert by any means. I know some assembly but im also only proficient.

    Thanks in advance for any help

    - Rory
    Last edited by rj.alaskan; 11-05-2010 at 09:06 PM. Reason: Forgot stuff

  2. #2
    and the hat of int overfl Salem's Avatar
    Join Date
    Aug 2001
    The edge of the known universe
    Given the signalling voltages, I wouldn't risk making a direct electrical connection to you USB (and PC).

    I would suggest going here -> Jan Axelson's Lakeview Research
    In particular, there is a large USB section, and also a web forum.

    For what it's worth, I think you need something like this
    blueroomelectronics Unicorn kit
    There are 100's of kits like this which sit on the end of a USB cable, and allow you to do all sorts of interesting things. With a bit of digging on LVR (and google), you should be able to find something a lot closer to what you want.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  3. #3
    Registered User
    Join Date
    Nov 2010
    Thanks for the reply. Ive checked out that link and that Unicorn kit looks like a cool bit of hardware. I'll look into this and see what i come up with.

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. superhighspeed usb 3.0
    By kryptkat in forum Tech Board
    Replies: 14
    Last Post: 08-16-2010, 10:07 PM
  2. [Hardware + Software][C++ or C#] USB Fan
    By Mywk in forum C++ Programming
    Replies: 16
    Last Post: 07-04-2009, 03:12 PM
  3. Write protecting USB drive
    By stevesmithx in forum Tech Board
    Replies: 8
    Last Post: 01-17-2009, 04:37 PM
  4. usb programming
    By ygfperson in forum A Brief History of
    Replies: 7
    Last Post: 07-24-2002, 08:06 PM
  5. Printers On USB
    By (TNT) in forum A Brief History of
    Replies: 1
    Last Post: 03-10-2002, 11:48 AM