LinuxQuestions.org
View the Most Wanted LQ Wiki articles.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Newbie
User Name
Password
Linux - Newbie This Linux forum is for members that are new to Linux.
Just starting out and have a question? If it is not in the man pages or the how-to's this is the place!

Notices

Reply
 
Search this Thread
Old 01-04-2013, 10:43 AM   #1
JonCombat
LQ Newbie
 
Registered: Jan 2013
Posts: 1

Rep: Reputation: Disabled
USB Low Level commands (embedded Linux, terminal commands)


I am a Linux newb. I need to test a USB port on a device. I would like to test it like a comport (short tx/rx together, send char, read char). Is it possible to send a char or just to toggle the tx line high so I can measure the status change? Also, to does a command exist to simply read the status of the RX line. Here are my usb devices
root@TSSC:/$ lsusb
Bus 001 Device 001: ID 1d6b:0002
Bus 002 Device 001: ID 1d6b:0002
Bus 001 Device 002: ID 0424:7500
root@TSSC:/$
 
Old 01-04-2013, 12:52 PM   #2
theNbomr
LQ 5k Club
 
Registered: Aug 2005
Distribution: OpenSuse, Fedora, Redhat, Debian
Posts: 5,395
Blog Entries: 2

Rep: Reputation: 903Reputation: 903Reputation: 903Reputation: 903Reputation: 903Reputation: 903Reputation: 903Reputation: 903
You could do what you are proposing iff there was some sort of device which looks like a serial port plugged into the USB port. USB, in and of itself, is a bus used by other devices. The device drivers that use USB provide the mechanism for sending and receiving data. There are a couple of USB-Serial chips that are well supported in Linux; FTDI is one, and the other eludes my recollection at the moment. There is no userspace software that I know of that lets you control (send & receive data) the USB bus itself directly.

--- rod.
 
Old 01-05-2013, 02:34 PM   #3
onebuck
Moderator
 
Registered: Jan 2005
Location: Midwest USA, Central Illinois
Distribution: Slackware®
Posts: 11,281
Blog Entries: 3

Rep: Reputation: 1446Reputation: 1446Reputation: 1446Reputation: 1446Reputation: 1446Reputation: 1446Reputation: 1446Reputation: 1446Reputation: 1446Reputation: 1446
Member Response

Hi,

You can look at: Introduction to FTDI bitbang mode
Quote:
It was an interface that launched a thousand hacks. Near trivial to program, enough I/O lines for useful work, and sufficiently fast for a multitude of applications: homebrew logic analyzers, chip programmers, LCD interfaces and LED light shows, to name a few.
Today the parallel printer port is on the brink of extinction (and good riddance, some would say). Largely rendered obsolete by USB, few (if any) new peripherals even include a parallel connector, and today’s shrinking computers — nettops, netbooks, media center PCs — wouldn’t have space for it anyway. That’s great for tidy desks, but not so good if you enjoyed the dirt-cheap hacks that the legacy parallel port made possible.
You can use USB FTDI TTL-232 cable - TTL-232R 3.3V from Boardino;
Quote:
This is a FTDI FT232RL usb/serial chip embedded in a cable that has a 6-pin socket at the end. These are perfect for use with a Boarduino, Meggy's, or other Arduino clones, and Fuzeboxen. Useful whenever you want to communicate with a TTL serial device, such as an XPort, GPS, XBee or SIM module through a breakout board. The version we have is the 3.3V. The data signals are at 3V and the power line provides 5V. We suggest this for any product that needs FTDI cables. Because the cable is 5V compliant, you can use it with 3v or 5v logic just fine - no level shifting required!.
If you have a device that is running at 5V logic and requires 5V power, this cable will work fine.
If you want to tweak the voltages and signals a little, you should also check out the FTDI friend
You can download the drivers and datasheet direct from FTDI
If you want a hardware solution then 'Boarduino is an Arduino clone'

HTH!
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need help for Windows cmd commands into Linux terminal commands. windowsNilo Linux - Software 2 07-02-2008 06:26 PM
Need help for Windows cmd commands into Linux terminal commands. windowsNilo Linux - General 2 07-01-2008 06:53 AM
Using Terminal commands in Linux Tec1 Linux - Newbie 2 11-03-2003 01:30 PM


All times are GMT -5. The time now is 02:31 AM.

Main Menu
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration