Unable to program custom nrf9160 board or chip through nrf9160DK.

[sawaiz]

I have made a custom board with a nrf9160 and am trying to program it via the nrf9160DK. In my testing I was unable to get it to show up or program, although the programmer was set to program an external device.

To make sure the problem is not with the soldering and missing pads on the custom board,I have a deadbug style breakout of the chip. I broke out and connected the following pins, and probed all connections to be correct. This is pictured. The custom board had decoupling as well although I could add it to this one too.

Pin 102 - VDD
Pin 101 - Enable, connected to VDD though 1k resistor
Pin 103 - Ground pad (checked continuity to all other ground pins)
Pin  34 - SWDIO
Pin  33 - SWDCLK
Pin  32 - NRST

These are all connected through jumpers to the P20 header. And the Ground on the P1 header. I have tested VDD being set to 1.8V as well as 3V. Also tried using the 5V pin on P1 as VDD.

(PGRM) -> (Board)
VDD    -> VDD
VTG    -> VDD
SWDIO  -> SWDIO
SWDCLK -> SWDCLK
RST    -> NRST
GND    -> GND

The device shows up as a J-Link sometimes and trying to connect gives the following error.

15:11:46.923
Unsupported device. The detected device could not be recognized as neither JLink device nor Nordic USB device.

Sometimes although VTG is connected to VDD, the device shows still up as the 9160DK, when trying to connect or erase from this state. I get the following errors.

15:00:09.076
Using @nordicsemiconductor/nrf-device-lib-js to communicate with target via JLink
15:00:09.076
JLink OB firmware version J-Link OB-K22-NordicSemi compiled Dec 3 2021 15:46:55
15:00:09.076
Device family NRF91_FAMILY
15:00:09.077
Device version NRF9160_xxAA_REV2
15:00:09.077
Board version PCA10090
15:00:09.077
Loading readback protection status for Application core
15:00:09.867
Failed to load readback protection status: async task failure for id: 1540052083 msg: [jlink] JLINKARM_DLL_ERROR (Origin: "Error when running operation: protection-get")
15:00:09.868
Modem detected
15:00:09.872
Parse memory regions for Application core
15:00:09.874
Update files regions according to Application core
15:00:09.874
Parse memory regions for file
15:00:09.879
Device is loaded and ready for further operation

Am I missing any connections or is there any method of more diagnostic info to see why I cam not getting a connection to the external chip? Would trying to read the SWD lines provide any insight?

[Torje]

Hello,

Just a thought: Is SW9 on the DK flipped to 3v?

[Simonr]

Hi

Try flipping SW9 as Torje suggests in order to match the voltage level of the external board with the VDD of the nRF9160 DK.

Best regards,

Simon

[sawaiz]

SW9 was set to 3V, In my testing both 3V and 1.8V gave the same error. Checking with a multimeter, the VDD of 3V is being applied to the chip. 

The programmer versions are all updated and is 3.0.6, and nrfConnect for desktop is 4.0.0, but using the older nrfConnect for desktop gave the same issues.

We have order another 9160dk and a nrf53dk and some 10pin swd cables. When those come in I can test to see if its an issue with the current programer, by trying to program two new boards from each other. 

[Simonr]

Okay, thank you for checking. I don't think your DK is the issue, and at a second glance at your setup, it seems like your VIO pin is floating which is likely causing issues for you.

Best regards,

Simon

[sawaiz]

Hello,

The VIO pin was floating, so I connected it to VDD and nothing changed. We received the 5340DK and connecting that allowed it to work immediacy, along with the custom board. It seems like the programing chip on the 9160DK is damaged on my board. I was also able to program the chip on the old board with the 5340DK.

Out of curiosity for the actual minimum viable connections needed for future debugging, I removed the VDD_GPIO leaving it floating. It was still able to program, although with the pin being floating and no knowledge of internal defaults, that isn't really guaranteed. I was also able to remove the nRST pin and was still able to program.

So the minimum connections are VDD, EN, SWDIO, SWDCLK, and GND should allow you to program a chip. Thanks for the help, I think this can be closed.

Regards,

Sawaiz