nRF52 DK not detected through USB

[emlynkz]

Hi,

after having issues with my devkit flashing the main MCU, the interface MCU isn't being seen on USB anymore.

LED5 is blinking rapidly.

 nrf52 DK keeps resecuring itself 

The board is a PCA10040 v3.0.4 with the nRF5340 as interface MCU.

All the documentation is only about the older version with the Atmel MCU, which can be recovered with its bootloader.

Is a similar thing possible with the v3.x and up?

I have access to other devkits and programmers.

Thanks!

Étienne Machabée

Lynkz Instruments Inc.

[JONATHAN LL]

Hi, 

Can you share the info that is on the sticker with us ?

And just to confirm that the nRF52 on the DK is working, can you try to use another DK or external programmer to program the "broken" DK?


Regards,
Jonathan

[emlynkz]

Hi,

yes I can flash with an external programmer the target nRF52 on the DK. It's only the J-Link portion that is not working.

The sticker says

PCA10040

3.0.4

2024.19

1050384200

Thanks,

Étienne Machabée

[JONATHAN LL]

Thanks for the info. 

Recovery on the Debugger\J-Link portion is not possible so dont try anything there. That was only an option on the older versions with a different chip. 

Are you able to probe the data lines of the USB? 
If the LED5 is blinking it indicates that the device is not able to communicate with the computer for some reason. 


Regards,
Jonathan

[emlynkz]

I probed the datalines on the USB for a brand new DK that is working. This is what I see.

On the DK with the issue, there's no traffic on the data lines.

This is using the exact same cable and computer. I just plugged and unplugged the DKs to switch and switched my Logic Analyzer.

[PaKa]

Very interesting, can you show exactly where on the kit you probed? Also, would it be possible to check with an oscilloscope probe as well? Would tell us if there is any activity on the lines not strong enough to trigger the logic analyzer.

[emlynkz]

I probed on the pads of the TVS which are connected to TP1 and TP2.

Following are measurements at TP1 with an oscilloscope:

The first screenshot is on a properly functionning DK.

The second screenshot is on the defective DK.

[JONATHAN LL]

What is the voltage on SB29 and SB36?



Regards,
Jonathan

[emlynkz]

Hi Jonathan, here are the requested voltages:

SB29 -> 3.035V

SB36 -> 3.034V

Étienne Machabée
Lynkz Instruments Inc