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shamanhugh

Beginner

Date of registration: Jun 9th 2017

Posts: 5

1

Friday, June 9th 2017, 1:04pm

[SOLVED] Rasperry pi 3, VTarget = 0.000V. Pin and cable are tested by multimeter and show 3.26V.

Hi,

I am trying to debug my rasperry pi 3 using J-Link edu. I connect the pins as following (The links are generated and made public by dropbox).

https://www.dropbox.com/s/76mba0selrayuq…nk-pin.png?dl=0

And I am using J-Link Commander v4.92 on my Win 7 Ultimate. However, when I 'st' and 'hwinfo', I get the following output.

https://www.dropbox.com/s/oa9s7rwjbzi6r5…nk-out.png?dl=0

I have tested pin 1 on rasberry pi 3 using multimeter and it's showing 3.26V. Then I test the output of pin 1 on the other side of the jtag cable , it also gives me 3.26V.

Can anyone help me out?

Thank you!

This post has been edited 3 times, last edit by "shamanhugh" (Jun 9th 2017, 1:11pm)


SEGGER - Niklas

Super Moderator

Date of registration: Oct 6th 2014

Posts: 1,619

2

Friday, June 9th 2017, 3:28pm

Hi,


in the pinout it says that pin 1 is connected to N/A.
You need to connect pin 1 of J-Link to a pin of the raspberry which provides VTREF / VDD.


Best regards,
Niklas
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shamanhugh

Beginner

Date of registration: Jun 9th 2017

Posts: 5

3

Friday, June 9th 2017, 7:54pm

Hi,

Thank you for your reply. N/A there simply means it is not GPIO.

Please refer the pinout of rasperry pi 3 as following.

https://www.dropbox.com/s/zljag7f2j5lf6hy/pi3_gpio.png?dl=0


Thank you!

SEGGER - Niklas

Super Moderator

Date of registration: Oct 6th 2014

Posts: 1,619

4

Friday, June 9th 2017, 8:09pm

Hi,


in order to be able to communicate with the target, you need to connect a ref voltage of the pi to Pin 1 of the J-Link.

Quoted

Pin 1 (VTREF) is the target reference voltage.
It is used to check if the target has power, to create the logic-level reference for the input comparators and to control the output logic levels to the target. It is normally fed from Vdd of the target board and must not have a series resistor.


The 20 pin JTAG/SWD pinout of J-Link can be found here:
https://www.segger.com/products/debug-pr…ace-description


Best regards,
Niklas
Would you like to be added to the J-Link software update notification list, so you get informed automatically when a new version becomes available?
Just write me a PM or in case you want to subscribe to it yourself, please use this link: Link
Notification for J-Link, J-Link Debugger, SystemView & J-Scope: Link
Notification for Embedded Studio: Link

shamanhugh

Beginner

Date of registration: Jun 9th 2017

Posts: 5

5

Friday, June 9th 2017, 8:26pm

Hi,

I have connected the pin 1 on rasperry pi to pin 1 on j-link. I think I get this right. And I have used multimeter to double check.

My question is, why it still telling me target power low even if I have already connected the right pins.

Thank you!

SEGGER - Niklas

Super Moderator

Date of registration: Oct 6th 2014

Posts: 1,619

6

Monday, June 12th 2017, 9:23am

Hi,


Sorry, I misread what you had written before.

Well first of all V4.92 is pretty ancient.
While it should work though, could you please give the current version of the J-Link software & documentation pack a try?

What happens if you connect a 3.3V Battery or "Lab Voltage" to Pin 1 and Pin 4?
Please note that Pin 14/16/18/20 are reserved on current J-Link probes.

Best regards,
Niklas
Would you like to be added to the J-Link software update notification list, so you get informed automatically when a new version becomes available?
Just write me a PM or in case you want to subscribe to it yourself, please use this link: Link
Notification for J-Link, J-Link Debugger, SystemView & J-Scope: Link
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shamanhugh

Beginner

Date of registration: Jun 9th 2017

Posts: 5

7

Monday, June 12th 2017, 3:00pm

Hi,

I am using J-Link Commander V6.4b now. And I have connected two AA 1.5V batteries to get 3.18V voltage. I connect the + and - side of them to the pin 1 and pin 4 respectively. But still, the J-Link commmender is complaining VTref = 0.000V.

Thank you!

SEGGER - Niklas

Super Moderator

Date of registration: Oct 6th 2014

Posts: 1,619

8

Monday, June 12th 2017, 6:31pm

Hi,

Quoted

J-Link Commander V6.4b

There is no version named "V6.4b". Are you referring to "6.14b"? If yes, why did you not download the latest version (V6.16b) instead of a "random" version?

Quoted

And I have connected two AA 1.5V batteries to get 3.18V voltage. I connect the + and - side of them to the pin 1 and pin 4 respectively. But still, the J-Link commmender is complaining VTref = 0.000V.

If this is the case, and you did not confuse the pins somehow, the J-Link is broken.
For J-Link EDU, you need to contact the reseller regarding the RMA procedure.


Best regards,
Niklas
Would you like to be added to the J-Link software update notification list, so you get informed automatically when a new version becomes available?
Just write me a PM or in case you want to subscribe to it yourself, please use this link: Link
Notification for J-Link, J-Link Debugger, SystemView & J-Scope: Link
Notification for Embedded Studio: Link

shamanhugh

Beginner

Date of registration: Jun 9th 2017

Posts: 5

9

Monday, June 12th 2017, 9:11pm

Hi,

I don't know why I typed 6.4b... I was using 6.16b. Sorry about that.

Yea, I will contact the seller.

Thank you for your help!

Sincerely,
Ruide