nRF52840 DK J-link not working

[GaryS]

Hi - I'm using a nRF52840 DK for the first time with my 2010 MacBook pro running OSX Sierra version 10.12.6. I have SEGGER Embedded Studio for ARM 4.12 installed and Segger J-link V6.40 tools running in /Applications/SEGGER/JLink. My DK board has a PCA10056 debugger chip v1.0.0. 

I have the Power switch on the DK board set to on, coin cell battery removed, power switch set to VDD. 

When I connect the DK board to my Mac via micro USB cable, I see LED5 blinking about once a second, and LED1 pulsating about once per 3 sec. 

The big problem I'm having is that I can't get the Segger Embedded Studio to see the DK; when I select "Connect J-Link" in the Target menu, I keep getting a "Can't connect to J-Link via USB" pop-up. 

Also, I don't consistently see a "JLINK" drive widget in my Finder window. And even when I do see it and tell Segger ES to connect to the board, it ejects the JLINK drive and fails to connect as it does in all other cases. 

Any ideas?

Thanks. 

[GaryS]

Hi - I don't think it's in BOOTLOADER mode because it doesn't say "BOOTLOADER" in the left side of the Finder window. I can put it in bootloader mode though by powering it up while holding down the reset button. Should I do that and copy the file where you suggested?

[GaryS]

I power-cycled it while holding down reset key, copied the file into BOOTLOADER drive folder, then power cycled again, but it didn't fix any of the strange behaviors. 

[AndreasF]

Hi again.

Please try/confirm the following:

1. Does the device show up in System Information on your computer? Please try to connect and disconnect the kit a few times. It might show up with unexpected names.

Search for System Information in Lion or later (or System Profiler in Snow Leopard and earlier versions of Mac OS) in Spotlight (press ⌘ and Space).

The program is in /Applications/Utilities and is the tool to see the connected USB devices and other hardware details. It is quite simliar to Device Manager on Windows.

Alternatively you can access it via the Apple Menu

 -> About This Mac -> More Info... -> System Report...

2. Have you tried a different USB cable? Faulty cables are surprisingly often the problem.

3. Have you tried using a different computer? If it works on a different computer we know that the kit is not broken and that it is probably a driver issue.

4. Have you measured the supply voltage on the kit? It should be somewhere between 2.8V-3.3V. If it isn't, then the hardware is probably broken.

5. Have you made sure that you are using the latest J-Link driver version?

6. Have you tried this guide?

Best regards,

Andreas

[GaryS]

OK, here's the answer to your question 1. I plugged the USB cable into my mac 5 times. In one of those 5 times, I saw this in my system report

and saw a JLINK drive icon in my finder window (see below):

After the remaining four plug-ins, there was no JLINK drive shown in my finder window and the system report didn't include the MSD Volume info, as shown below. I'll answer your other questions sequentially after some more time. 

[GaryS]

2. Tried another cable - no joy, unfortunately. 

3. Will try a different computer later. 

4. Will measure supply voltage later. 

5. Regarding Jlink version, I'm running V6.40 which I think is the latest version. Most times when I run /Applications/SEGGER/JLink/JLinkExe it fails right away like this:

Gary-Sugars-MacBook-Pro:~ gsugar$ /Applications/SEGGER/JLink/JLinkExe
SEGGER J-Link Commander V6.40 (Compiled Oct 26 2018 15:07:23)
DLL version V6.40, compiled Oct 26 2018 15:07:12

Connecting to J-Link via USB...FAILED: Cannot connect to J-Link via USB.

Sometimes (when the JLINK drive icon appears in finder window) I see this:

Gary-Sugars-MacBook-Pro:~ gsugar$ /Applications/SEGGER/JLink/JLinkExe
SEGGER J-Link Commander V6.40 (Compiled Oct 26 2018 15:07:23)
DLL version V6.40, compiled Oct 26 2018 15:07:12

Connecting to J-Link via USB...Updating firmware: J-Link OB-SAM3U128-V2-NordicSemi compiled Jul 12 2018 11:44:41
Replacing firmware: J-Link OB-SAM3U128-V2-NordicSemi compiled Jul 24 2017 17:30:12
FAILED: Communication timeout. Emulator did not re-enumerate.

[GaryS]

6. Since I can't connect to the DK via JLinkExe, I would think that this approach won't work. Let me know if you disagree. 

[GaryS]

OK here's some good news ... I just rebooted my Mac and got everything to work somehow. Here's what happened when I ran JLinkExe after reboot:

SEGGER J-Link Commander V6.40 (Compiled Oct 26 2018 15:07:23)
DLL version V6.40, compiled Oct 26 2018 15:07:12

Connecting to J-Link via USB...Updating firmware: J-Link OB-SAM3U128-V2-NordicSemi compiled Jul 12 2018 11:44:41
Replacing firmware: J-Link OB-SAM3U128-V2-NordicSemi compiled Jul 24 2017 17:30:12
Waiting for new firmware to boot
New firmware booted successfully
O.K.
Firmware: J-Link OB-SAM3U128-V2-NordicSemi compiled Jul 12 2018 11:44:41
Hardware version: V1.00
S/N: 683009000
VTref=3.300V

I then ran the Segger Embedded Studio app, selected Target->Connect J-Link, and saw the screen below. Repeatedly disconnected and reconnected several times and it still works. Not sure how I got this to work, but it seems to now. Yuck - hope most folks have an easier time of this than I did! Thanks for your help. 

[AndreasF]

Hi.

Great to hear that you got it working.

Best regards,

Andreas