On 2/28/19 8:54 AM, John Vaughters via TriEmbed wrote:
> But I need to go a step further. To assign a name like "NW-FOO" to the
XDS110 in the NW corner of my "test range" I'd need to interpose in
Udev somehow so it could do the thing to determine which is which.
Right, so are you saying that you do not have unique serial #'s?. The
technique described relies on specific devices with serial numbers,
I'm struggling to understand what you mean exactly by serial number in
this context. Does each USB interface chip (or emulation hardware) have
a unique serial number along with the manufacturer ID and device ID that
we see with lsusb? I just assumed they don't and it's up to me to
extract a standard ID (such as can be programmed into the debug probes)
or something ad hoc (e.g. with a custom Arduino boot loader recognizing
a "gimme your UID" command).
I went backwards from you, spending about 10 years with Debian Stable
before going to the dark side with Ubuntu 13. I regret that, but am
afraid some key tool my work depends on simply won't play with what was
a solid rock of reliability. Maybe I should grease up VirtualBox and see
if I could reverse course.
-Pete
so if you have to change an Arduino Nano out for instance, you would
also need to change the rule to use the new serial number. UDEV is
extremely flexible and I haven't even touched the surface of it, so if
you write more generic rules to just capture Arduino vs XYX, then I am
sure you could find a rule to increment your naming. I used this
technique to utilize the serial number to always connect to a specific
name. It worked quite well for fixing reconnects where it would
normally increment. However, it still did not fix just plain
disconnects common in USB. I am not a fan of the USB software layer
and I absolutely despise its physical connections. Having said all
that I still use it in many ways, I have to, it's all there is for
many things. And this solution described with UDEV and serial #'s
actually worked quite well at solving the vast majority of issues and
was quite stable. Probably fine for non-critical uses.
Example FTDI Serial #
ATTRS{serial}=="A600G5OZ"
>I regret going with Ubuntu 18.04
You are making me feel better about keeping my Ubuntu 16 or is it 14?
Anyway, I am done with Ubuntu. it drives me crazy in the same way that
windows does, by making decisions for you and assuming the user needs
to be probed constantly to act. I have always been a RedHat person,
but thanks to Rpi and many other embedded devices, I am now a HUGE fan
of Debian. I will not be going to Ubuntu for new installs unless I am
setting it up for non-technical users, then Ubuntu is still the #1 go
to. For me though, Ubuntu just annoys the crap out of me in so many
ways. The problem with RedHat (Centos) is it just doesn't keep up to
date for newer software, so I have to use something else for that. It
has been Ubuntu, but now it's Debian.
On Wednesday, February 27, 2019, 8:55:07 PM EST, Pete Soper via
TriEmbed <[email protected]> wrote:
On 2/27/19 7:16 PM, John Vaughters via TriEmbed wrote:
Pete,
If you are using the same USB devices all the time and do not expect
changes, consider doing udev rules. Below is an article I wrote about
it. Basically it recognizes your USB device based on certain ID's and
you can name the device whatever you want. As far as communicating,
"expect" scripts is as good as any tool I can think of. The only thing
that is probably
Thanks. That's a nice how-to and will make it easy to differentiate
between the TI XDS110 debug probes and Beaglebone boards that both
manifest as /dev/ttyACMn and between instances of custom devices and
the Arduino Nano's I'm using to run some motors that both manifest as
/dev/ttyUSBn. But I need to go a step further. To assign a name like
"NW-FOO" to the XDS110 in the NW corner of my "test range" I'd need to
interpose in Udev somehow so it could do the thing to determine which
is which. For the XDS110 there's a TI program that (if you repeat it
enough times: flaky as heck) puts out strings including the ID string,
but for the custom device I need to use expect to poke something into
the port and get back the ID (and same for the Arduino motor
controllers).
So the question is whether there's a hook mechanism with Udev that
would allow running a command as a side effect of the device's
detection and name assignment under /dev. Especially if that could be
run as root I could create the symbolic link and properly set its
group id. Or maybe the invoked program/script could simply rename the
device after it's probed it?
I agree that USB has got further to go. I regret going with Ubuntu
18.04 for my latest PC 'cause Code Composer Studio seems to be much
less able to manage the debug probes than when it's running on 16.04.
Over on the TriLUG list there's been griping about 18.04 having
regressions and that matches my experience.
-Pete
better is Tera-Term, but that is strictly windows. It is quite good
though and I wrote a tool to run scripts to 300 edge routers using
Tera-Term. One thing I used to do is use "socat" to send the serial
device to a raw TCP port and communicate over the network. In general
I do everything I can to not communicate to USB devices due to their
constant connection issues. I prefer using UART if possible.
Good Luck,
John Vaughters
Arduino Communications Device Naming with udev - Combustory
<http://combustory.com/wiki/index.php/Arduino_Communications_Device_Naming_with_udev>
Arduino Communications Device Naming with udev - Combustory
<http://combustory.com/wiki/index.php/Arduino_Communications_Device_Naming_with_udev>
On Wednesday, February 27, 2019, 4:41:50 PM EST, Pete Soper via
TriEmbed <[email protected]> <mailto:[email protected]> wrote:
It's been many years since I used the Unix "expect" command but that was
the industrial strength solution for automated interaction with a serial
connection such as via ssh where you specify a "script" of "this is
sent, this is what's received back", interactions and the logic to take
actions based on the interaction details. What's out there now that I
should be using, or is this still the best way to go? My host
environment choices are Linux or Cygwin (inside a VM).
My situation is that I have three or four flavors of device that I need
to connect to with either ssh or a terminal emulator where a script of
some sort dictates what I have to send and what I expect back. This, in
turn, is to deal with the musical chair situation with USB connections
such as when I get intermittent electrical service from Duke Energy (at
no extra cost!) I've got an automated test system where there are, for
example, /dev/ttyACM{0,1,2,3,4,5,6,7}, /dev/USB{0,1,2,3}, etc, and I
need to establish and keep fresh meaninfully named symlinks that get
associated with the right devices assigned randomly by system startups,
being forced to unconnect/reconnect cables, etc.
.
Thanks,
Pete
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