Is there a way to pre-set / force JLink to never power or try power the board? I don't know if this make sense though, tbh ..

Basically, if my board is powered externally or from another USB source, I wouldn't want JLink to power it. What I see is, if I unplug power , say to reset whole system, JLink is supplying some power, and I have to unplug it to fully power down the board.
But I'm not sure if it's expected behaviour - is it sensing no power and then supplying it .. ?

I have tried to set power off permanently, by using the JLinkExe command shell , perm power off. But that doens't seem to persist , as on next GDBServer start it does, seems, put power back.

Hi Nino,

That is what I have tried originally. It doesnt' seem to work with this unit - JLink EDU.

I have the more expensive J-Trace, and I can see it is 'smart' enough to sense accurately when the board is powered (I observe it reacts with the led very quick every time i turn on/off the board).

My J-Trace is too good for this board though ...

I get 0.589V when just plugging the Cortex plug into the board, the J-Link EDU, with no external power on.

If I power the board then, connect JLinkExe, set power off perm, and then turn off power supply, I get a constant reading 1.867V on the board, coming from J-Link.
And then quitting from JLink , "q", seems to put it back around 0.9V ....

Is that normal? I think not.

With my J-Trace, it's ~ 0.0..V to start, and back to 0 with off.

So J-Link EDU is probably to cheap, and leaks current into the board .. ?

Tested now, I read ~1.3+ V on J-Link pins after doing "power off perm", with no devboard connected ...
Tried re-plugging it USB, same thing.

I realized I had a Segger USB J-Link Isolator lying around..

So with J-Link EDU connected through the isolator, I 've brought it down to < 30 mV. Now my devboard stays off when I turn power off at least.

The J-Link EDU seems is a little dodge, not worth the price _if_ you need isolator with it:
At my Mouser
- J-Link EDU: approx $20
- Segger USB isolator: approx $300 !! (whaaat?) and not in stock anyway .

Next cheapest non-Segger isolator is approx $50.

Hi,

Could you clarify which isolator you are currently using?

USB Isolator -> segger.com/products/debug-prob…tors/j-link-usb-isolator/

Does the same behavior occur when using another target board?

Yes, I have purchased identical other / copy board. Also, have you not seen my above post, where you asked me to measure on pins with no board connected .. ?

Could you measure the voltage of the J-Link's 5V-pin when power off perm is used?

Have you not seen my above post ? Nov 8th 2019, Please see above.

Do you get the same Voltage reading there?

Ok, now I'm unsure about which pin you asking : I used pin 1 (red ribbon) & ground.

Could you provide us with your J-Link EDU's serial number for reference?

Yes, I can. Please provide your email where I can send it. As this is private info which can uniquely identify me, I do not wish to share it on my public posts.

In which context did you use the J-Link EDU?

I see where you think you going, but it will be denied . I'm using this specific J-Link EDU for educational purposes, as I'm enrolled into a student program.
If your license management dept would like my info on that, please provide email where I can send it - but appropriate contact. (I'm ready to email them my course in-progress registration).

I also have a couple of J-Link EDU now: the original I'm having issue with, as reported here - J-Link EDU mini (tiny un-sealed/unboxed one), and J-Link EDU , white box, not tested yet even by me.
Can I get as many as I want.. ? Or do I have to be enrolled in separate course for each ... :D.

Could you elaborate?

Oh yes, I can with pleasure. As mentioned above, those are for educational use. The board used - for education / course. Hope that is elaborate enough.

In Addition (means, I also have .. ) I own a J-Trace Pro Cortex, which is not restricted to Education only use. (And in fact, was purchased by my company). But, on that, I could have filed support through ticketing system...I guess.

I hope these answers on your questions you had about licensing and my intended and actual use case, with licensing concerns, have been sufficiently answered by me here. On the thread about me having J-Link leaking current.

Please do not hesitate to request serial numbers by email to appropriate Segger department!

Best regards

Hey Fabian,
If you see above - I did already, see post from Oct 31st 2019 on this thread. I will re-check.

I will re-try with my J-Link EDU too, not mini, haven't had chance yet.

I can assure you, that we did not link the SN of any J-Link to any of our customers personal information at any openly accessible platform.

Yea but your distributors , whom I buy most, may. In any event, I can PM you / email you/Segger. No issues .

Please do not yet close this thread. I may take few days to reply due to travel.

Hello Fabian,

Issue does not appear with my JTrace, or, the non-mini EDU.

I would then like to return my EDU for replacement (or refund). [I understand that it's in-expensive, but, as it was like this from new I don't like to purchase broken hardware]

Please provide steps how I can return it to Segger or, the distributor? I suppose they may want to know what is broken in it, and my guess it's easier if Segger support gave me an official email saying that so I can pass it to them.

I will message (or email if you provide) you the SN for the unit and others.

Fabian,

Yea sorry for confusion : it is the J-Link EDU MINI that I _think_ /believe I have issue with, not J-Link EDU . ( The latter I used to re-test and , wrote that I don't observe problems with).


I PM'ed you asking if you still want my serials over a week ago ... I haven't received any replies, so perhaps you not getting PM's? I will send my serials to PM.

Please see your message box : you should have 2 messages from me now , one from 2nd Jan (on another matter) and one I sent just now with the serial numbers.
Please acknowledge that you have received them.

Hey Fabian, will do asap with photo & details, but i'm on something else this week and/or few days.