DUT powered without ui

Technical Discussion
1

Is it possible to leave the DUT powered when exiting the joulescope_ui?

joulescope_ui : 1.0.29
joulescope driver : 1.3.18
joulescope : JS110

2

Hi @kada and welcome to the Joulescope forum!

I think that the default Joulescope UI behavior is to leave the JS110 working when you exit the UI.

I just did a quick test. Upon exit, the JS110’s sensor-side LED (under IN) remained illuminated and the target remained powered.

Is this not what you find?

3

No, Every time I close the joulescope_ui the LED is turned off and the DUT is turned off.
There is maybe a delay of 1sek from the time that the ui is closed and until the LED turns off.
The LED comes back on when the ui is executed again.

4

I used Windows 11 for the quick test. What OS are you using?

5

Linux Manjaro:

$ cat /etc/lsb-release 
DISTRIB_ID="ManjaroLinux"
DISTRIB_RELEASE="23.0.0"
DISTRIB_CODENAME="Uranos"
DISTRIB_DESCRIPTION="Manjaro Linux"

$ uname -a
Linux esja 6.4.12-1-MANJARO #1 SMP PREEMPT_DYNAMIC Thu Aug 24 17:37:05 UTC 2023 x86_64 GNU/Linux
6

I just tried this on Ubuntu 22.04 LTS, and the JS110 remains powered. So, I suspect something about how Manjaro Linux handles USB devices.

This sounds like the OS is performing a USB suspend on the JS110. I found this in a quick search for “manjaro linux disable usb suspend”. Does this help?

7

Thank you, Adding

ATTR{power/autosuspend}="-1"

to the udev rule solved the issue, i.e. it now looks like:

ACTION=="add", SUBSYSTEM=="usb", ATTR{idVendor}=="05c6", ATTR{idProduct}=="9205", ATTR{power/autosuspend}="-1"
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